clean up with develop branch

* Add bellatrix forkchoice spec tests

* Update service.go

* better conversion

.bazelrc

@@ -217,3 +217,6 @@ build:remote --remote_local_fallback
 
 # Ignore GoStdLib with remote caching
 build --modify_execution_info='GoStdlib.*=+no-remote-cache'
+
+# Set bazel gotag
+build --define gotags=bazel

.bazelversion

@@ -1 +1 @@
-4.2.2
+5.0.0

.buildkite-bazelrc

@@ -10,31 +10,31 @@
 
 # Prysm specific remote-cache properties.
 #build:remote-cache --disk_cache=
-build:remote-cache --remote_download_toplevel
+build:remote-cache --remote_download_minimal
 build:remote-cache --remote_cache=grpc://bazel-remote-cache:9092
 build:remote-cache --experimental_remote_downloader=grpc://bazel-remote-cache:9092
 build:remote-cache --remote_local_fallback
+build:remote-cache --experimental_remote_cache_async
+build:remote-cache --experimental_remote_merkle_tree_cache
+build:remote-cache --experimental_action_cache_store_output_metadata
+build:remote-cache --experimental_remote_cache_compression
 # Enforce stricter environment rules, which eliminates some non-hermetic
 # behavior and therefore improves both the remote cache hit rate and the
 # correctness and repeatability of the build.
 build:remote-cache --incompatible_strict_action_env=true
 
+build --experimental_use_hermetic_linux_sandbox
+
 # Import workspace options.
 import %workspace%/.bazelrc
 
-startup --host_jvm_args=-Xmx2g --host_jvm_args=-Xms2g
-query --repository_cache=/tmp/repositorycache
-query --experimental_repository_cache_hardlinks
-build --repository_cache=/tmp/repositorycache
-build --experimental_repository_cache_hardlinks
+startup --host_jvm_args=-Xmx4g --host_jvm_args=-Xms2g
 build --experimental_strict_action_env
-build --disk_cache=/tmp/bazelbuilds
-build --experimental_multi_threaded_digest
 build --sandbox_tmpfs_path=/tmp
 build --verbose_failures
 build --announce_rc
 build --show_progress_rate_limit=5
-build --curses=yes --color=no
+build --curses=no --color=no
 build --keep_going
 build --test_output=errors
 build --flaky_test_attempts=5

BUILD.bazel

@@ -3,7 +3,7 @@ load("@com_github_atlassian_bazel_tools//gometalinter:def.bzl", "gometalinter")
 load("@com_github_atlassian_bazel_tools//goimports:def.bzl", "goimports")
 load("@io_kubernetes_build//defs:run_in_workspace.bzl", "workspace_binary")
 load("@io_bazel_rules_go//go:def.bzl", "nogo")
-load("@graknlabs_bazel_distribution//common:rules.bzl", "assemble_targz", "assemble_versioned")
+load("@vaticle_bazel_distribution//common:rules.bzl", "assemble_targz", "assemble_versioned")
 load("@bazel_skylib//rules:common_settings.bzl", "string_setting")
 
 prefix = "github.com/prysmaticlabs/prysm"
@@ -16,6 +16,8 @@ exports_files([
 # gazelle:map_kind go_library go_library @prysm//tools/go:def.bzl
 # gazelle:map_kind go_test go_test @prysm//tools/go:def.bzl
 # gazelle:map_kind go_repository go_repository @prysm//tools/go:def.bzl
+# gazelle:build_tags bazel
+# gazelle:exclude tools/analyzers/**/testdata/**
 gazelle(
     name = "gazelle",
     prefix = prefix,
@@ -125,6 +127,7 @@ nogo(
         "//tools/analyzers/ineffassign:go_default_library",
         "//tools/analyzers/properpermissions:go_default_library",
         "//tools/analyzers/recursivelock:go_default_library",
+        "//tools/analyzers/uintcast:go_default_library",
     ] + select({
         # nogo checks that fail with coverage enabled.
         ":coverage_enabled": [],

WORKSPACE

@@ -117,13 +117,6 @@ http_archive(
     urls = ["https://github.com/fuzzitdev/fuzzit/releases/download/v2.4.76/fuzzit_Linux_x86_64.zip"],
 )
 
-git_repository(
-    name = "graknlabs_bazel_distribution",
-    commit = "962f3a7e56942430c0ec120c24f9e9f2a9c2ce1a",
-    remote = "https://github.com/graknlabs/bazel-distribution",
-    shallow_since = "1569509514 +0300",
-)
-
 load(
     "@io_bazel_rules_docker//repositories:repositories.bzl",
     container_repositories = "repositories",
@@ -222,7 +215,7 @@ filegroup(
     url = "https://github.com/eth-clients/slashing-protection-interchange-tests/archive/b8413ca42dc92308019d0d4db52c87e9e125c4e9.tar.gz",
 )
 
-consensus_spec_version = "v1.1.9"
+consensus_spec_version = "v1.1.10"
 
 bls_test_version = "v0.1.1"
 
@@ -238,7 +231,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    sha256 = "207d9c326ba4fa1f34bab7b6169201c32f2611755db030909a3405873445e0ba",
+    sha256 = "28043009cc2f6fc9804e73c8c1fc2cb27062f1591e6884f3015ae1dd7a276883",
     url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/general.tar.gz" % consensus_spec_version,
 )
 
@@ -254,7 +247,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    sha256 = "a3995b39f412db236b2f1db909f288218da53cb53b9923b71dda9d144d68f40a",
+    sha256 = "bc1a283ca068f310f04d70c4f6a8eaa0b8f7e9318073a8bdc2ee233111b4e339",
     url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/minimal.tar.gz" % consensus_spec_version,
 )
 
@@ -270,7 +263,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    sha256 = "76cea7a4c8e32d458ad456b54bfbb30bc772481a91954a4cd97e229aa3023b1d",
+    sha256 = "bbabb482c229ff9d4e2c7b77c992edb452f9d0af7c6d8dd4f922f06a7b101e81",
     url = "https://github.com/ethereum/consensus-spec-tests/releases/download/%s/mainnet.tar.gz" % consensus_spec_version,
 )
 
@@ -285,7 +278,7 @@ filegroup(
     visibility = ["//visibility:public"],
 )
     """,
-    sha256 = "0fc429684775f943250dce1f9c485ac25e26c6395d7f585c8d1317becec2ace7",
+    sha256 = "408a5524548ad3fcf387f65ac7ec52781d9ee899499720bb12451b48a15818d4",
     strip_prefix = "consensus-specs-" + consensus_spec_version[1:],
     url = "https://github.com/ethereum/consensus-specs/archive/refs/tags/%s.tar.gz" % consensus_spec_version,
 )

async/multilock_test.go

@@ -110,9 +110,8 @@ func TestLockUnlock_CleansUnused(t *testing.T) {
 		lock := NewMultilock("dog", "cat", "owl")
 		lock.Lock()
 		assert.Equal(t, 3, len(locks.list))
-		defer lock.Unlock()
+		lock.Unlock()
 
-		<-time.After(100 * time.Millisecond)
 		wg.Done()
 	}()
 	wg.Wait()

beacon-chain/blockchain/BUILD.bazel

@@ -7,7 +7,6 @@ go_library(
         "error.go",
         "head.go",
         "head_sync_committee_info.go",
-        "info.go",
         "init_sync_process_block.go",
         "log.go",
         "metrics.go",
@@ -50,6 +49,7 @@ go_library(
         "//beacon-chain/db:go_default_library",
         "//beacon-chain/db/filters:go_default_library",
         "//beacon-chain/forkchoice:go_default_library",
+        "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
         "//beacon-chain/forkchoice/protoarray:go_default_library",
         "//beacon-chain/operations/attestations:go_default_library",
         "//beacon-chain/operations/slashings:go_default_library",
@@ -74,7 +74,6 @@ go_library(
         "//runtime/version:go_default_library",
         "//time:go_default_library",
         "//time/slots:go_default_library",
-        "@com_github_emicklei_dot//:go_default_library",
         "@com_github_ethereum_go_ethereum//common:go_default_library",
         "@com_github_ethereum_go_ethereum//common/hexutil:go_default_library",
         "@com_github_holiman_uint256//:go_default_library",
@@ -104,7 +103,6 @@ go_test(
         "checktags_test.go",
         "head_sync_committee_info_test.go",
         "head_test.go",
-        "info_test.go",
         "init_test.go",
         "log_test.go",
         "metrics_test.go",

beacon-chain/blockchain/chain_info.go

@@ -6,6 +6,8 @@ import (
 
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice"
+	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
@@ -53,12 +55,12 @@ type HeadFetcher interface {
 	HeadETH1Data() *ethpb.Eth1Data
 	HeadPublicKeyToValidatorIndex(pubKey [fieldparams.BLSPubkeyLength]byte) (types.ValidatorIndex, bool)
 	HeadValidatorIndexToPublicKey(ctx context.Context, index types.ValidatorIndex) ([fieldparams.BLSPubkeyLength]byte, error)
-	ProtoArrayStore() *protoarray.Store
 	ChainHeads() ([][32]byte, []types.Slot)
 	IsOptimistic(ctx context.Context) (bool, error)
-	IsOptimisticForRoot(ctx context.Context, root [32]byte, slot types.Slot) (bool, error)
+	IsOptimisticForRoot(ctx context.Context, root [32]byte) (bool, error)
 	HeadSyncCommitteeFetcher
 	HeadDomainFetcher
+	ForkChoicer() forkchoice.ForkChoicer
 }
 
 // ForkFetcher retrieves the current fork information of the Ethereum beacon chain.
@@ -238,11 +240,6 @@ func (s *Service) HeadETH1Data() *ethpb.Eth1Data {
 	return s.head.state.Eth1Data()
 }
 
-// ProtoArrayStore returns the proto array store object.
-func (s *Service) ProtoArrayStore() *protoarray.Store {
-	return s.cfg.ForkChoiceStore.Store()
-}
-
 // GenesisTime returns the genesis time of beacon chain.
 func (s *Service) GenesisTime() time.Time {
 	return s.genesisTime
@@ -288,23 +285,7 @@ func (s *Service) IsCanonical(ctx context.Context, blockRoot [32]byte) (bool, er
 // ChainHeads returns all possible chain heads (leaves of fork choice tree).
 // Heads roots and heads slots are returned.
 func (s *Service) ChainHeads() ([][32]byte, []types.Slot) {
-	nodes := s.ProtoArrayStore().Nodes()
-
-	// Deliberate choice to not preallocate space for below.
-	// Heads cant be more than 2-3 in the worst case where pre-allocation will be 64 to begin with.
-	headsRoots := make([][32]byte, 0)
-	headsSlots := make([]types.Slot, 0)
-
-	nonExistentNode := ^uint64(0)
-	for _, node := range nodes {
-		// Possible heads have no children.
-		if node.BestDescendant() == nonExistentNode && node.BestChild() == nonExistentNode {
-			headsRoots = append(headsRoots, node.Root())
-			headsSlots = append(headsSlots, node.Slot())
-		}
-	}
-
-	return headsRoots, headsSlots
+	return s.cfg.ForkChoiceStore.Tips()
 }
 
 // HeadPublicKeyToValidatorIndex returns the validator index of the `pubkey` in current head state.
@@ -331,6 +312,11 @@ func (s *Service) HeadValidatorIndexToPublicKey(_ context.Context, index types.V
 	return v.PublicKey(), nil
 }
 
+// ForkChoicer returns the forkchoice interface
+func (s *Service) ForkChoicer() forkchoice.ForkChoicer {
+	return s.cfg.ForkChoiceStore
+}
+
 // IsOptimistic returns true if the current head is optimistic.
 func (s *Service) IsOptimistic(ctx context.Context) (bool, error) {
 	s.headLock.RLock()
@@ -339,16 +325,52 @@ func (s *Service) IsOptimistic(ctx context.Context) (bool, error) {
 		return false, nil
 	}
 
-	return s.cfg.ForkChoiceStore.Optimistic(ctx, s.head.root, s.head.slot)
+	return s.IsOptimisticForRoot(ctx, s.head.root)
 }
 
 // IsOptimisticForRoot takes the root and slot as aguments instead of the current head
 // and returns true if it is optimistic.
-func (s *Service) IsOptimisticForRoot(ctx context.Context, root [32]byte, slot types.Slot) (bool, error) {
-	return s.cfg.ForkChoiceStore.Optimistic(ctx, root, slot)
+func (s *Service) IsOptimisticForRoot(ctx context.Context, root [32]byte) (bool, error) {
+	optimistic, err := s.cfg.ForkChoiceStore.IsOptimistic(ctx, root)
+	if err == nil {
+		return optimistic, nil
+	}
+	if err != protoarray.ErrUnknownNodeRoot && err != doublylinkedtree.ErrNilNode {
+		return false, err
+	}
+	ss, err := s.cfg.BeaconDB.StateSummary(ctx, root)
+	if err != nil {
+		return false, err
+	}
+	if ss == nil {
+		return false, errInvalidNilSummary
+	}
+
+	validatedCheckpoint, err := s.cfg.BeaconDB.LastValidatedCheckpoint(ctx)
+	if err != nil {
+		return false, err
+	}
+	if slots.ToEpoch(ss.Slot) > validatedCheckpoint.Epoch {
+		return true, nil
+	}
+
+	if slots.ToEpoch(ss.Slot)+1 < validatedCheckpoint.Epoch {
+		return false, nil
+	}
+
+	lastValidated, err := s.cfg.BeaconDB.StateSummary(ctx, bytesutil.ToBytes32(validatedCheckpoint.Root))
+	if err != nil {
+		return false, err
+	}
+	return ss.Slot > lastValidated.Slot, nil
 }
 
 // SetGenesisTime sets the genesis time of beacon chain.
 func (s *Service) SetGenesisTime(t time.Time) {
 	s.genesisTime = t
 }
+
+// ForkChoiceStore returns the fork choice store in the service
+func (s *Service) ForkChoiceStore() forkchoice.ForkChoicer {
+	return s.cfg.ForkChoiceStore
+}

beacon-chain/blockchain/chain_info_norace_test.go

@@ -16,10 +16,13 @@ func TestHeadSlot_DataRace(t *testing.T) {
 	s := &Service{
 		cfg: &config{BeaconDB: beaconDB},
 	}
+	wait := make(chan struct{})
 	go func() {
+		defer close(wait)
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
 	s.HeadSlot()
+	<-wait
 }
 
 func TestHeadRoot_DataRace(t *testing.T) {
@@ -28,11 +31,14 @@ func TestHeadRoot_DataRace(t *testing.T) {
 		cfg:  &config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
 		head: &head{root: [32]byte{'A'}},
 	}
+	wait := make(chan struct{})
 	go func() {
+		defer close(wait)
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
 	_, err := s.HeadRoot(context.Background())
 	require.NoError(t, err)
+	<-wait
 }
 
 func TestHeadBlock_DataRace(t *testing.T) {
@@ -41,11 +47,14 @@ func TestHeadBlock_DataRace(t *testing.T) {
 		cfg:  &config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
 		head: &head{block: wrapper.WrappedPhase0SignedBeaconBlock(&ethpb.SignedBeaconBlock{})},
 	}
+	wait := make(chan struct{})
 	go func() {
+		defer close(wait)
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
 	_, err := s.HeadBlock(context.Background())
 	require.NoError(t, err)
+	<-wait
 }
 
 func TestHeadState_DataRace(t *testing.T) {
@@ -53,9 +62,12 @@ func TestHeadState_DataRace(t *testing.T) {
 	s := &Service{
 		cfg: &config{BeaconDB: beaconDB, StateGen: stategen.New(beaconDB)},
 	}
+	wait := make(chan struct{})
 	go func() {
+		defer close(wait)
 		require.NoError(t, s.saveHead(context.Background(), [32]byte{}))
 	}()
 	_, err := s.HeadState(context.Background())
 	require.NoError(t, err)
+	<-wait
 }

beacon-chain/blockchain/chain_info_test.go

@@ -8,6 +8,7 @@ import (
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
+	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	v1 "github.com/prysmaticlabs/prysm/beacon-chain/state/v1"
 	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
@@ -40,6 +41,12 @@ func TestHeadRoot_Nil(t *testing.T) {
 	assert.DeepEqual(t, params.BeaconConfig().ZeroHash[:], headRoot, "Incorrect pre chain start value")
 }
 
+func TestService_ForkChoiceStore(t *testing.T) {
+	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New(0, 0)}}
+	p := c.ForkChoiceStore()
+	require.Equal(t, 0, int(p.FinalizedEpoch()))
+}
+
 func TestFinalizedCheckpt_CanRetrieve(t *testing.T) {
 	beaconDB := testDB.SetupDB(t)
 
@@ -277,27 +284,40 @@ func TestService_HeadGenesisValidatorsRoot(t *testing.T) {
 	root = c.HeadGenesisValidatorsRoot()
 	require.DeepEqual(t, root[:], s.GenesisValidatorsRoot())
 }
-
-func TestService_ProtoArrayStore(t *testing.T) {
-	c := &Service{cfg: &config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}}
-	p := c.ProtoArrayStore()
-	require.Equal(t, 0, int(p.FinalizedEpoch()))
-}
-
-func TestService_ChainHeads(t *testing.T) {
+func TestService_ChainHeads_ProtoArray(t *testing.T) {
 	ctx := context.Background()
-	c := &Service{cfg: &config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}}
-	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, [32]byte{}, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, [32]byte{}, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, [32]byte{}, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 103, [32]byte{'d'}, [32]byte{}, [32]byte{}, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 104, [32]byte{'e'}, [32]byte{'b'}, [32]byte{}, 0, 0))
+	c := &Service{cfg: &config{ForkChoiceStore: protoarray.New(0, 0,
+		params.BeaconConfig().ZeroHash)}}
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 103, [32]byte{'d'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 104, [32]byte{'e'}, [32]byte{'b'}, 0, 0))
 
 	roots, slots := c.ChainHeads()
 	require.DeepEqual(t, [][32]byte{{'c'}, {'d'}, {'e'}}, roots)
 	require.DeepEqual(t, []types.Slot{102, 103, 104}, slots)
 }
 
+func TestService_ChainHeads_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New(0, 0)}}
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 103, [32]byte{'d'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 104, [32]byte{'e'}, [32]byte{'b'}, 0, 0))
+
+	roots, slots := c.ChainHeads()
+	require.Equal(t, 3, len(roots))
+	rootMap := map[[32]byte]types.Slot{[32]byte{'c'}: 102, [32]byte{'d'}: 103, [32]byte{'e'}: 104}
+	for i, root := range roots {
+		slot, ok := rootMap[root]
+		require.Equal(t, true, ok)
+		require.Equal(t, slot, slots[i])
+	}
+}
+
 func TestService_HeadPublicKeyToValidatorIndex(t *testing.T) {
 	s, _ := util.DeterministicGenesisState(t, 10)
 	c := &Service{}
@@ -356,7 +376,7 @@ func TestService_HeadValidatorIndexToPublicKeyNil(t *testing.T) {
 	require.Equal(t, [fieldparams.BLSPubkeyLength]byte{}, p)
 }
 
-func TestService_IsOptimistic(t *testing.T) {
+func TestService_IsOptimistic_ProtoArray(t *testing.T) {
 	params.SetupTestConfigCleanup(t)
 	cfg := params.BeaconConfig()
 	cfg.BellatrixForkEpoch = 0
@@ -364,8 +384,24 @@ func TestService_IsOptimistic(t *testing.T) {
 
 	ctx := context.Background()
 	c := &Service{cfg: &config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}, head: &head{slot: 101, root: [32]byte{'b'}}}
-	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, [32]byte{}, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, 0, 0))
+
+	opt, err := c.IsOptimistic(ctx)
+	require.NoError(t, err)
+	require.Equal(t, true, opt)
+}
+
+func TestService_IsOptimistic_DoublyLinkedTree(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig()
+	cfg.BellatrixForkEpoch = 0
+	params.OverrideBeaconConfig(cfg)
+
+	ctx := context.Background()
+	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New(0, 0)}, head: &head{slot: 101, root: [32]byte{'b'}}}
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, 0, 0))
 
 	opt, err := c.IsOptimistic(ctx)
 	require.NoError(t, err)
@@ -380,13 +416,100 @@ func TestService_IsOptimisticBeforeBellatrix(t *testing.T) {
 	require.Equal(t, false, opt)
 }
 
-func TestService_IsOptimisticForRoot(t *testing.T) {
+func TestService_IsOptimisticForRoot_ProtoArray(t *testing.T) {
 	ctx := context.Background()
 	c := &Service{cfg: &config{ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}, head: &head{slot: 101, root: [32]byte{'b'}}}
-	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, [32]byte{}, 0, 0))
-	require.NoError(t, c.cfg.ForkChoiceStore.ProcessBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, 0, 0))
 
-	opt, err := c.IsOptimisticForRoot(ctx, [32]byte{'a'}, 100)
+	opt, err := c.IsOptimisticForRoot(ctx, [32]byte{'a'})
 	require.NoError(t, err)
 	require.Equal(t, true, opt)
 }
+
+func TestService_IsOptimisticForRoot_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+	c := &Service{cfg: &config{ForkChoiceStore: doublylinkedtree.New(0, 0)}, head: &head{slot: 101, root: [32]byte{'b'}}}
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, [32]byte{}, 0, 0))
+	require.NoError(t, c.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, 0, 0))
+
+	opt, err := c.IsOptimisticForRoot(ctx, [32]byte{'a'})
+	require.NoError(t, err)
+	require.Equal(t, true, opt)
+}
+
+func TestService_IsOptimisticForRoot_DB_ProtoArray(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	ctx := context.Background()
+	c := &Service{cfg: &config{BeaconDB: beaconDB, ForkChoiceStore: protoarray.New(0, 0, [32]byte{})}, head: &head{slot: 101, root: [32]byte{'b'}}}
+	c.head = &head{root: params.BeaconConfig().ZeroHash}
+	b := util.NewBeaconBlock()
+	b.Block.Slot = 10
+	br, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(context.Background(), wrapper.WrappedPhase0SignedBeaconBlock(b)))
+	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: br[:], Slot: 10}))
+
+	optimisticBlock := util.NewBeaconBlock()
+	optimisticBlock.Block.Slot = 11
+	optimisticRoot, err := optimisticBlock.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(context.Background(), wrapper.WrappedPhase0SignedBeaconBlock(optimisticBlock)))
+
+	validatedBlock := util.NewBeaconBlock()
+	validatedBlock.Block.Slot = 9
+	validatedRoot, err := validatedBlock.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(context.Background(), wrapper.WrappedPhase0SignedBeaconBlock(validatedBlock)))
+
+	validatedCheckpoint := &ethpb.Checkpoint{Root: br[:]}
+	require.NoError(t, beaconDB.SaveLastValidatedCheckpoint(ctx, validatedCheckpoint))
+
+	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: optimisticRoot[:], Slot: 11}))
+	optimistic, err := c.IsOptimisticForRoot(ctx, optimisticRoot)
+	require.NoError(t, err)
+	require.Equal(t, true, optimistic)
+
+	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: validatedRoot[:], Slot: 9}))
+	validated, err := c.IsOptimisticForRoot(ctx, validatedRoot)
+	require.NoError(t, err)
+	require.Equal(t, false, validated)
+}
+
+func TestService_IsOptimisticForRoot__DB_DoublyLinkedTree(t *testing.T) {
+	beaconDB := testDB.SetupDB(t)
+	ctx := context.Background()
+	c := &Service{cfg: &config{BeaconDB: beaconDB, ForkChoiceStore: doublylinkedtree.New(0, 0)}, head: &head{slot: 101, root: [32]byte{'b'}}}
+	c.head = &head{root: params.BeaconConfig().ZeroHash}
+	b := util.NewBeaconBlock()
+	b.Block.Slot = 10
+	br, err := b.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(context.Background(), wrapper.WrappedPhase0SignedBeaconBlock(b)))
+	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: br[:], Slot: 10}))
+
+	optimisticBlock := util.NewBeaconBlock()
+	optimisticBlock.Block.Slot = 11
+	optimisticRoot, err := optimisticBlock.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(context.Background(), wrapper.WrappedPhase0SignedBeaconBlock(optimisticBlock)))
+
+	validatedBlock := util.NewBeaconBlock()
+	validatedBlock.Block.Slot = 9
+	validatedRoot, err := validatedBlock.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, beaconDB.SaveBlock(context.Background(), wrapper.WrappedPhase0SignedBeaconBlock(validatedBlock)))
+
+	validatedCheckpoint := &ethpb.Checkpoint{Root: br[:]}
+	require.NoError(t, beaconDB.SaveLastValidatedCheckpoint(ctx, validatedCheckpoint))
+
+	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: optimisticRoot[:], Slot: 11}))
+	optimistic, err := c.IsOptimisticForRoot(ctx, optimisticRoot)
+	require.NoError(t, err)
+	require.Equal(t, true, optimistic)
+
+	require.NoError(t, beaconDB.SaveStateSummary(context.Background(), &ethpb.StateSummary{Root: validatedRoot[:], Slot: 9}))
+	validated, err := c.IsOptimisticForRoot(ctx, validatedRoot)
+	require.NoError(t, err)
+	require.Equal(t, false, validated)
+}

beacon-chain/blockchain/checktags_test.go

@@ -1,3 +1,4 @@
+//go:build !develop
 // +build !develop
 
 package blockchain

beacon-chain/blockchain/error.go

@@ -9,4 +9,8 @@ var (
 	errNilBestJustifiedInStore = errors.New("nil best justified checkpoint returned from store")
 	// errNilFinalizedInStore is returned when a nil finalized checkpt is returned from store.
 	errNilFinalizedInStore = errors.New("nil finalized checkpoint returned from store")
+	// errInvalidNilSummary is returned when a nil summary is returned from the DB.
+	errInvalidNilSummary = errors.New("nil summary returned from the DB")
+	// errNilParentInDB is returned when a nil parent block is returned from the DB.
+	errNilParentInDB = errors.New("nil parent block in DB")
 )

beacon-chain/blockchain/head.go

@@ -10,6 +10,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/feed"
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
+	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/config/features"
@@ -77,7 +78,11 @@ func (s *Service) updateHead(ctx context.Context, balances []uint64) error {
 		if err != nil {
 			return err
 		}
-		s.cfg.ForkChoiceStore = protoarray.New(j.Epoch, f.Epoch, bytesutil.ToBytes32(f.Root))
+		if features.Get().EnableForkChoiceDoublyLinkedTree {
+			s.cfg.ForkChoiceStore = doublylinkedtree.New(j.Epoch, f.Epoch)
+		} else {
+			s.cfg.ForkChoiceStore = protoarray.New(j.Epoch, f.Epoch, bytesutil.ToBytes32(f.Root))
+		}
 		if err := s.insertBlockToForkChoiceStore(ctx, jb.Block(), headStartRoot, f, j); err != nil {
 			return err
 		}

beacon-chain/blockchain/info.go

@@ -1,99 +0,0 @@
-package blockchain
-
-import (
-	"encoding/hex"
-	"fmt"
-	"net/http"
-
-	"github.com/emicklei/dot"
-	"github.com/prysmaticlabs/prysm/config/params"
-)
-
-const template = `<html>
-<head>
-    <script src="//cdnjs.cloudflare.com/ajax/libs/viz.js/2.1.2/viz.js"></script>
-    <script src="//cdnjs.cloudflare.com/ajax/libs/viz.js/2.1.2/full.render.js"></script>
-<body>
-    <script type="application/javascript">
-        var graph = ` + "`%s`;" + `
-        var viz = new Viz();
-        viz.renderSVGElement(graph) // reading the graph.
-            .then(function(element) {
-                document.body.appendChild(element); // appends to document.
-            })
-            .catch(error => {
-                // Create a new Viz instance (@see Caveats page for more info)
-                viz = new Viz();
-                // Possibly display the error
-                console.error(error);
-            });
-    </script>
-</head>
-</body>
-</html>`
-
-// TreeHandler is a handler to serve /tree page in metrics.
-func (s *Service) TreeHandler(w http.ResponseWriter, r *http.Request) {
-	headState, err := s.HeadState(r.Context())
-	if err != nil {
-		log.WithError(err).Error("Could not get head state")
-		return
-	}
-	if headState == nil || headState.IsNil() {
-		if _, err := w.Write([]byte("Unavailable during initial syncing")); err != nil {
-			log.WithError(err).Error("Failed to render p2p info page")
-		}
-	}
-
-	nodes := s.cfg.ForkChoiceStore.Nodes()
-
-	graph := dot.NewGraph(dot.Directed)
-	graph.Attr("rankdir", "RL")
-	graph.Attr("labeljust", "l")
-
-	dotNodes := make([]*dot.Node, len(nodes))
-	avgBalance := uint64(averageBalance(headState.Balances()))
-
-	for i := len(nodes) - 1; i >= 0; i-- {
-		// Construct label for each node.
-		slot := fmt.Sprintf("%d", nodes[i].Slot())
-		weight := fmt.Sprintf("%d", nodes[i].Weight()/1e9) // Convert unit Gwei to unit ETH.
-		votes := fmt.Sprintf("%d", nodes[i].Weight()/1e9/avgBalance)
-		index := fmt.Sprintf("%d", i)
-		g := nodes[i].Graffiti()
-		graffiti := hex.EncodeToString(g[:8])
-		label := "slot: " + slot + "\n votes: " + votes + "\n weight: " + weight + "\n graffiti: " + graffiti
-		var dotN dot.Node
-		if nodes[i].Parent() != ^uint64(0) {
-			dotN = graph.Node(index).Box().Attr("label", label)
-		}
-
-		if nodes[i].Slot() == s.HeadSlot() &&
-			nodes[i].BestDescendant() == ^uint64(0) &&
-			nodes[i].Parent() != ^uint64(0) {
-			dotN = dotN.Attr("color", "green")
-		}
-
-		dotNodes[i] = &dotN
-	}
-
-	for i := len(nodes) - 1; i >= 0; i-- {
-		if nodes[i].Parent() != ^uint64(0) && nodes[i].Parent() < uint64(len(dotNodes)) {
-			graph.Edge(*dotNodes[i], *dotNodes[nodes[i].Parent()])
-		}
-	}
-
-	w.WriteHeader(http.StatusOK)
-	w.Header().Set("Content-Type", "text/html")
-	if _, err := fmt.Fprintf(w, template, graph.String()); err != nil {
-		log.WithError(err).Error("Failed to render p2p info page")
-	}
-}
-
-func averageBalance(balances []uint64) float64 {
-	total := uint64(0)
-	for i := 0; i < len(balances); i++ {
-		total += balances[i]
-	}
-	return float64(total) / float64(len(balances)) / float64(params.BeaconConfig().GweiPerEth)
-}

beacon-chain/blockchain/info_test.go

@@ -1,50 +0,0 @@
-package blockchain
-
-import (
-	"context"
-	"net/http"
-	"net/http/httptest"
-	"testing"
-
-	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
-	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
-	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
-	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
-	"github.com/prysmaticlabs/prysm/testing/assert"
-	"github.com/prysmaticlabs/prysm/testing/require"
-	"github.com/prysmaticlabs/prysm/testing/util"
-)
-
-func TestService_TreeHandler(t *testing.T) {
-	req, err := http.NewRequest("GET", "/tree", nil)
-	require.NoError(t, err)
-
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	headState, err := util.NewBeaconState()
-	require.NoError(t, err)
-	require.NoError(t, headState.SetBalances([]uint64{params.BeaconConfig().GweiPerEth}))
-	fcs := protoarray.New(
-		0, // justifiedEpoch
-		0, // finalizedEpoch
-		[32]byte{'a'},
-	)
-	opts := []Option{
-		WithDatabase(beaconDB),
-		WithStateGen(stategen.New(beaconDB)),
-		WithForkChoiceStore(fcs),
-	}
-	s, err := NewService(ctx, opts...)
-	require.NoError(t, err)
-	require.NoError(t, s.cfg.ForkChoiceStore.ProcessBlock(ctx, 0, [32]byte{'a'}, [32]byte{'g'}, [32]byte{'c'}, 0, 0))
-	require.NoError(t, s.cfg.ForkChoiceStore.ProcessBlock(ctx, 1, [32]byte{'b'}, [32]byte{'a'}, [32]byte{'c'}, 0, 0))
-	s.setHead([32]byte{'a'}, wrapper.WrappedPhase0SignedBeaconBlock(util.NewBeaconBlock()), headState)
-
-	rr := httptest.NewRecorder()
-	handler := http.HandlerFunc(s.TreeHandler)
-
-	handler.ServeHTTP(rr, req)
-
-	assert.Equal(t, http.StatusOK, rr.Code)
-}

beacon-chain/blockchain/log.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/prysmaticlabs/prysm/config/params"
+	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
 	"github.com/prysmaticlabs/prysm/runtime/version"
@@ -17,7 +18,7 @@ import (
 var log = logrus.WithField("prefix", "blockchain")
 
 // logs state transition related data every slot.
-func logStateTransitionData(b block.BeaconBlock) {
+func logStateTransitionData(b block.BeaconBlock) error {
 	log := log.WithField("slot", b.Slot())
 	if len(b.Body().Attestations()) > 0 {
 		log = log.WithField("attestations", len(b.Body().Attestations()))
@@ -34,13 +35,23 @@ func logStateTransitionData(b block.BeaconBlock) {
 	if len(b.Body().VoluntaryExits()) > 0 {
 		log = log.WithField("voluntaryExits", len(b.Body().VoluntaryExits()))
 	}
-	if b.Version() == version.Altair {
+	if b.Version() == version.Altair || b.Version() == version.Bellatrix {
 		agg, err := b.Body().SyncAggregate()
-		if err == nil {
-			log = log.WithField("syncBitsCount", agg.SyncCommitteeBits.Count())
+		if err != nil {
+			return err
 		}
+		log = log.WithField("syncBitsCount", agg.SyncCommitteeBits.Count())
+	}
+	if b.Version() == version.Bellatrix {
+		p, err := b.Body().ExecutionPayload()
+		if err != nil {
+			return err
+		}
+		log = log.WithField("payloadHash", fmt.Sprintf("%#x", bytesutil.Trunc(p.BlockHash)))
+		log = log.WithField("txCount", len(p.Transactions))
 	}
 	log.Info("Finished applying state transition")
+	return nil
 }
 
 func logBlockSyncStatus(block block.BeaconBlock, blockRoot [32]byte, finalized *ethpb.Checkpoint, receivedTime time.Time, genesisTime uint64) error {

beacon-chain/blockchain/log_test.go

@@ -3,6 +3,7 @@ package blockchain
 import (
 	"testing"
 
+	enginev1 "github.com/prysmaticlabs/prysm/proto/engine/v1"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
@@ -11,6 +12,17 @@ import (
 )
 
 func Test_logStateTransitionData(t *testing.T) {
+	payloadBlk := &ethpb.BeaconBlockBellatrix{
+		Body: &ethpb.BeaconBlockBodyBellatrix{
+			SyncAggregate: &ethpb.SyncAggregate{},
+			ExecutionPayload: &enginev1.ExecutionPayload{
+				BlockHash:    []byte{1, 2, 3},
+				Transactions: [][]byte{{}, {}},
+			},
+		},
+	}
+	wrappedPayloadBlk, err := wrapper.WrappedBeaconBlock(payloadBlk)
+	require.NoError(t, err)
 	tests := []struct {
 		name string
 		b    block.BeaconBlock
@@ -55,11 +67,15 @@ func Test_logStateTransitionData(t *testing.T) {
 				VoluntaryExits:    []*ethpb.SignedVoluntaryExit{{}}}}),
 			want: "\"Finished applying state transition\" attestations=1 attesterSlashings=1 deposits=1 prefix=blockchain proposerSlashings=1 slot=0 voluntaryExits=1",
 		},
+		{name: "has payload",
+			b:    wrappedPayloadBlk,
+			want: "\"Finished applying state transition\" payloadHash=0x010203 prefix=blockchain slot=0 syncBitsCount=0 txCount=2",
+		},
 	}
 	for _, tt := range tests {
 		hook := logTest.NewGlobal()
 		t.Run(tt.name, func(t *testing.T) {
-			logStateTransitionData(tt.b)
+			require.NoError(t, logStateTransitionData(tt.b))
 			require.LogsContain(t, hook, tt.want)
 		})
 	}

beacon-chain/blockchain/new_slot_test.go

@@ -25,11 +25,11 @@ func TestService_newSlot(t *testing.T) {
 	}
 	ctx := context.Background()
 
-	require.NoError(t, fcs.ProcessBlock(ctx, 0, [32]byte{}, [32]byte{}, [32]byte{}, 0, 0))        // genesis
-	require.NoError(t, fcs.ProcessBlock(ctx, 32, [32]byte{'a'}, [32]byte{}, [32]byte{}, 0, 0))    // finalized
-	require.NoError(t, fcs.ProcessBlock(ctx, 64, [32]byte{'b'}, [32]byte{'a'}, [32]byte{}, 0, 0)) // justified
-	require.NoError(t, fcs.ProcessBlock(ctx, 96, [32]byte{'c'}, [32]byte{'a'}, [32]byte{}, 0, 0)) // best justified
-	require.NoError(t, fcs.ProcessBlock(ctx, 97, [32]byte{'d'}, [32]byte{}, [32]byte{}, 0, 0))    // bad
+	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 0, [32]byte{}, [32]byte{}, 0, 0))        // genesis
+	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 32, [32]byte{'a'}, [32]byte{}, 0, 0))    // finalized
+	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 64, [32]byte{'b'}, [32]byte{'a'}, 0, 0)) // justified
+	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 96, [32]byte{'c'}, [32]byte{'a'}, 0, 0)) // best justified
+	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 97, [32]byte{'d'}, [32]byte{}, 0, 0))    // bad
 
 	type args struct {
 		slot          types.Slot

beacon-chain/blockchain/optimistic_sync.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 
 	"github.com/pkg/errors"
-	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	v1 "github.com/prysmaticlabs/prysm/beacon-chain/powchain/engine-api-client/v1"
@@ -13,6 +12,7 @@ import (
 	"github.com/prysmaticlabs/prysm/config/params"
 	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
 	enginev1 "github.com/prysmaticlabs/prysm/proto/engine/v1"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
 	"github.com/prysmaticlabs/prysm/runtime/version"
 	"github.com/sirupsen/logrus"
@@ -21,7 +21,7 @@ import (
 // notifyForkchoiceUpdate signals execution engine the fork choice updates. Execution engine should:
 // 1. Re-organizes the execution payload chain and corresponding state to make head_block_hash the head.
 // 2. Applies finality to the execution state: it irreversibly persists the chain of all execution payloads and corresponding state, up to and including finalized_block_hash.
-func (s *Service) notifyForkchoiceUpdate(ctx context.Context, headBlk block.BeaconBlock, finalizedRoot [32]byte) (*enginev1.PayloadIDBytes, error) {
+func (s *Service) notifyForkchoiceUpdate(ctx context.Context, headBlk block.BeaconBlock, headRoot [32]byte, finalizedRoot [32]byte) (*enginev1.PayloadIDBytes, error) {
 	if headBlk == nil || headBlk.IsNil() || headBlk.Body().IsNil() {
 		return nil, errors.New("nil head block")
 	}
@@ -76,12 +76,15 @@ func (s *Service) notifyForkchoiceUpdate(ctx context.Context, headBlk block.Beac
 			return nil, errors.Wrap(err, "could not notify forkchoice update from execution engine")
 		}
 	}
+	if err := s.cfg.ForkChoiceStore.SetOptimisticToValid(ctx, headRoot); err != nil {
+		return nil, errors.Wrap(err, "could not set block to valid")
+	}
 	return payloadID, nil
 }
 
 // notifyForkchoiceUpdate signals execution engine on a new payload
-func (s *Service) notifyNewPayload(ctx context.Context, preState, postState state.BeaconState, blk block.SignedBeaconBlock) error {
-	if preState == nil || postState == nil {
+func (s *Service) notifyNewPayload(ctx context.Context, preStateVersion int, header *ethpb.ExecutionPayloadHeader, postState state.BeaconState, blk block.SignedBeaconBlock) error {
+	if postState == nil {
 		return errors.New("pre and post states must not be nil")
 	}
 	// Execution payload is only supported in Bellatrix and beyond.
@@ -118,10 +121,12 @@ func (s *Service) notifyNewPayload(ctx context.Context, preState, postState stat
 	}
 
 	// During the transition event, the transition block should be verified for sanity.
-	if isPreBellatrix(preState.Version()) {
-		return nil
+	if isPreBellatrix(preStateVersion) {
+		// Handle case where pre-state is Altair but block contains payload.
+		// To reach here, the block must have contained a valid payload.
+		return s.validateMergeBlock(ctx, blk)
 	}
-	atTransition, err := blocks.MergeTransitionBlock(preState, body)
+	atTransition, err := blocks.IsMergeTransitionBlockUsingPayloadHeader(header, body)
 	if err != nil {
 		return errors.Wrap(err, "could not check if merge block is terminal")
 	}
@@ -140,14 +145,38 @@ func isPreBellatrix(v int) bool {
 //
 // Spec pseudocode definition:
 // def is_optimistic_candidate_block(opt_store: OptimisticStore, current_slot: Slot, block: BeaconBlock) -> bool:
-//     justified_root = opt_store.block_states[opt_store.head_block_root].current_justified_checkpoint.root
-//     justified_is_execution_block = is_execution_block(opt_store.blocks[justified_root])
-//     block_is_deep = block.slot + SAFE_SLOTS_TO_IMPORT_OPTIMISTICALLY <= current_slot
-//     return justified_is_execution_block or block_is_deep
+//    if is_execution_block(opt_store.blocks[block.parent_root]):
+//        return True
+//
+//    justified_root = opt_store.block_states[opt_store.head_block_root].current_justified_checkpoint.root
+//    if is_execution_block(opt_store.blocks[justified_root]):
+//        return True
+//
+//    if block.slot + SAFE_SLOTS_TO_IMPORT_OPTIMISTICALLY <= current_slot:
+//        return True
+//
+//    return False
 func (s *Service) optimisticCandidateBlock(ctx context.Context, blk block.BeaconBlock) (bool, error) {
 	if blk.Slot()+params.BeaconConfig().SafeSlotsToImportOptimistically <= s.CurrentSlot() {
 		return true, nil
 	}
+
+	parent, err := s.cfg.BeaconDB.Block(ctx, bytesutil.ToBytes32(blk.ParentRoot()))
+	if err != nil {
+		return false, err
+	}
+	if parent == nil {
+		return false, errNilParentInDB
+	}
+
+	parentIsExecutionBlock, err := blocks.ExecutionBlock(parent.Block().Body())
+	if err != nil {
+		return false, err
+	}
+	if parentIsExecutionBlock {
+		return true, nil
+	}
+
 	j := s.store.JustifiedCheckpt()
 	if j == nil {
 		return false, errNilJustifiedInStore
@@ -158,21 +187,3 @@ func (s *Service) optimisticCandidateBlock(ctx context.Context, blk block.Beacon
 	}
 	return blocks.ExecutionBlock(jBlock.Block().Body())
 }
-
-// loadSyncedTips loads a previously saved synced Tips from DB
-// if no synced tips are saved, then it creates one from the given
-// root and slot number.
-func (s *Service) loadSyncedTips(root [32]byte, slot types.Slot) error {
-	// Initialize synced tips
-	tips, err := s.cfg.BeaconDB.ValidatedTips(s.ctx)
-	if err != nil || len(tips) == 0 {
-		tips[root] = slot
-		if err != nil {
-			log.WithError(err).Warn("Could not read synced tips from DB, using finalized checkpoint as synced tip")
-		}
-	}
-	if err := s.cfg.ForkChoiceStore.SetSyncedTips(tips); err != nil {
-		return errors.Wrap(err, "could not set synced tips")
-	}
-	return nil
-}

beacon-chain/blockchain/optimistic_sync_test.go

@@ -17,6 +17,7 @@ import (
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
+	"github.com/prysmaticlabs/prysm/runtime/version"
 	"github.com/prysmaticlabs/prysm/testing/require"
 	"github.com/prysmaticlabs/prysm/testing/util"
 	"github.com/prysmaticlabs/prysm/time/slots"
@@ -35,7 +36,6 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 	require.NoError(t, err)
 	require.NoError(t, beaconDB.SaveBlock(ctx, altairBlk))
 	require.NoError(t, beaconDB.SaveBlock(ctx, bellatrixBlk))
-
 	fcs := protoarray.New(0, 0, [32]byte{'a'})
 	opts := []Option{
 		WithDatabase(beaconDB),
@@ -44,6 +44,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 	}
 	service, err := NewService(ctx, opts...)
 	require.NoError(t, err)
+	require.NoError(t, fcs.InsertOptimisticBlock(ctx, 0, [32]byte{}, [32]byte{}, 0, 0))
 
 	tests := []struct {
 		name             string
@@ -154,7 +155,7 @@ func Test_NotifyForkchoiceUpdate(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			engine := &mockEngineService{forkchoiceError: tt.newForkchoiceErr}
 			service.cfg.ExecutionEngineCaller = engine
-			_, err := service.notifyForkchoiceUpdate(ctx, tt.blk, tt.finalizedRoot)
+			_, err := service.notifyForkchoiceUpdate(ctx, tt.blk, service.headRoot(), tt.finalizedRoot)
 			if tt.errString != "" {
 				require.ErrorContains(t, tt.errString, err)
 			} else {
@@ -187,6 +188,13 @@ func Test_NotifyNewPayload(t *testing.T) {
 			},
 		},
 	}
+	a := &ethpb.SignedBeaconBlockAltair{
+		Block: &ethpb.BeaconBlockAltair{
+			Body: &ethpb.BeaconBlockBodyAltair{},
+		},
+	}
+	altairBlk, err := wrapper.WrappedSignedBeaconBlock(a)
+	require.NoError(t, err)
 	bellatrixBlk, err := wrapper.WrappedSignedBeaconBlock(blk)
 	require.NoError(t, err)
 	service, err := NewService(ctx, opts...)
@@ -211,7 +219,8 @@ func Test_NotifyNewPayload(t *testing.T) {
 			preState:  altairState,
 		},
 		{
-			name:      "nil states",
+			name:      "nil post state",
+			preState:  phase0State,
 			errString: "pre and post states must not be nil",
 		},
 		{
@@ -236,10 +245,29 @@ func Test_NotifyNewPayload(t *testing.T) {
 			errString:     "could not validate execution payload from execution engine: payload status is INVALID",
 		},
 		{
-			name:      "altair pre state",
+			name:      "altair pre state, altair block",
 			postState: bellatrixState,
 			preState:  altairState,
-			blk:       bellatrixBlk,
+			blk:       altairBlk,
+		},
+		{
+			name:      "altair pre state, happy case",
+			postState: bellatrixState,
+			preState:  altairState,
+			blk: func() block.SignedBeaconBlock {
+				blk := &ethpb.SignedBeaconBlockBellatrix{
+					Block: &ethpb.BeaconBlockBellatrix{
+						Body: &ethpb.BeaconBlockBodyBellatrix{
+							ExecutionPayload: &v1.ExecutionPayload{
+								ParentHash: bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength),
+							},
+						},
+					},
+				}
+				b, err := wrapper.WrappedSignedBeaconBlock(blk)
+				require.NoError(t, err)
+				return b
+			}(),
 		},
 		{
 			name:      "could not get merge block",
@@ -302,22 +330,29 @@ func Test_NotifyNewPayload(t *testing.T) {
 		},
 	}
 	for _, tt := range tests {
-		engine := &mockEngineService{newPayloadError: tt.newPayloadErr, blks: map[[32]byte]*v1.ExecutionBlock{}}
-		engine.blks[[32]byte{'a'}] = &v1.ExecutionBlock{
-			ParentHash:      bytesutil.PadTo([]byte{'b'}, fieldparams.RootLength),
-			TotalDifficulty: "0x2",
-		}
-		engine.blks[[32]byte{'b'}] = &v1.ExecutionBlock{
-			ParentHash:      bytesutil.PadTo([]byte{'3'}, fieldparams.RootLength),
-			TotalDifficulty: "0x1",
-		}
-		service.cfg.ExecutionEngineCaller = engine
-		err := service.notifyNewPayload(ctx, tt.preState, tt.postState, tt.blk)
-		if tt.errString != "" {
-			require.ErrorContains(t, tt.errString, err)
-		} else {
-			require.NoError(t, err)
-		}
+		t.Run(tt.name, func(t *testing.T) {
+			engine := &mockEngineService{newPayloadError: tt.newPayloadErr, blks: map[[32]byte]*v1.ExecutionBlock{}}
+			engine.blks[[32]byte{'a'}] = &v1.ExecutionBlock{
+				ParentHash:      bytesutil.PadTo([]byte{'b'}, fieldparams.RootLength),
+				TotalDifficulty: "0x2",
+			}
+			engine.blks[[32]byte{'b'}] = &v1.ExecutionBlock{
+				ParentHash:      bytesutil.PadTo([]byte{'3'}, fieldparams.RootLength),
+				TotalDifficulty: "0x1",
+			}
+			service.cfg.ExecutionEngineCaller = engine
+			var payload *ethpb.ExecutionPayloadHeader
+			if tt.preState.Version() == version.Bellatrix {
+				payload, err = tt.preState.LatestExecutionPayloadHeader()
+				require.NoError(t, err)
+			}
+			err := service.notifyNewPayload(ctx, tt.preState.Version(), payload, tt.postState, tt.blk)
+			if tt.errString != "" {
+				require.ErrorContains(t, tt.errString, err)
+			} else {
+				require.NoError(t, err)
+			}
+		})
 	}
 }
 
@@ -340,6 +375,12 @@ func Test_IsOptimisticCandidateBlock(t *testing.T) {
 	params.BeaconConfig().SafeSlotsToImportOptimistically = 128
 	service.genesisTime = time.Now().Add(-time.Second * 12 * 2 * 128)
 
+	parentBlk := util.NewBeaconBlockBellatrix()
+	wrappedParentBlock, err := wrapper.WrappedBellatrixSignedBeaconBlock(parentBlk)
+	require.NoError(t, err)
+	parentRoot, err := wrappedParentBlock.Block().HashTreeRoot()
+	require.NoError(t, err)
+
 	tests := []struct {
 		name      string
 		blk       block.BeaconBlock
@@ -351,6 +392,7 @@ func Test_IsOptimisticCandidateBlock(t *testing.T) {
 			blk: func(tt *testing.T) block.BeaconBlock {
 				blk := util.NewBeaconBlockBellatrix()
 				blk.Block.Slot = 1
+				blk.Block.ParentRoot = parentRoot[:]
 				wr, err := wrapper.WrappedBellatrixBeaconBlock(blk.Block)
 				require.NoError(tt, err)
 				return wr
@@ -358,6 +400,7 @@ func Test_IsOptimisticCandidateBlock(t *testing.T) {
 			justified: func(tt *testing.T) block.SignedBeaconBlock {
 				blk := util.NewBeaconBlockBellatrix()
 				blk.Block.Slot = 32
+				blk.Block.ParentRoot = parentRoot[:]
 				wr, err := wrapper.WrappedBellatrixSignedBeaconBlock(blk)
 				require.NoError(tt, err)
 				return wr
@@ -369,6 +412,7 @@ func Test_IsOptimisticCandidateBlock(t *testing.T) {
 			blk: func(tt *testing.T) block.BeaconBlock {
 				blk := util.NewBeaconBlockAltair()
 				blk.Block.Slot = 200
+				blk.Block.ParentRoot = parentRoot[:]
 				wr, err := wrapper.WrappedAltairBeaconBlock(blk.Block)
 				require.NoError(tt, err)
 				return wr
@@ -376,6 +420,7 @@ func Test_IsOptimisticCandidateBlock(t *testing.T) {
 			justified: func(tt *testing.T) block.SignedBeaconBlock {
 				blk := util.NewBeaconBlockAltair()
 				blk.Block.Slot = 32
+				blk.Block.ParentRoot = parentRoot[:]
 				wr, err := wrapper.WrappedAltairSignedBeaconBlock(blk)
 				require.NoError(tt, err)
 				return wr
@@ -387,6 +432,7 @@ func Test_IsOptimisticCandidateBlock(t *testing.T) {
 			blk: func(tt *testing.T) block.BeaconBlock {
 				blk := util.NewBeaconBlockBellatrix()
 				blk.Block.Slot = 200
+				blk.Block.ParentRoot = parentRoot[:]
 				wr, err := wrapper.WrappedBellatrixBeaconBlock(blk.Block)
 				require.NoError(tt, err)
 				return wr
@@ -394,6 +440,7 @@ func Test_IsOptimisticCandidateBlock(t *testing.T) {
 			justified: func(tt *testing.T) block.SignedBeaconBlock {
 				blk := util.NewBeaconBlockBellatrix()
 				blk.Block.Slot = 32
+				blk.Block.ParentRoot = parentRoot[:]
 				wr, err := wrapper.WrappedBellatrixSignedBeaconBlock(blk)
 				require.NoError(tt, err)
 				return wr
@@ -405,6 +452,7 @@ func Test_IsOptimisticCandidateBlock(t *testing.T) {
 			blk: func(tt *testing.T) block.BeaconBlock {
 				blk := util.NewBeaconBlockBellatrix()
 				blk.Block.Slot = 200
+				blk.Block.ParentRoot = parentRoot[:]
 				wr, err := wrapper.WrappedBellatrixBeaconBlock(blk.Block)
 				require.NoError(tt, err)
 				return wr
@@ -412,6 +460,7 @@ func Test_IsOptimisticCandidateBlock(t *testing.T) {
 			justified: func(tt *testing.T) block.SignedBeaconBlock {
 				blk := util.NewBeaconBlockBellatrix()
 				blk.Block.Slot = 32
+				blk.Block.ParentRoot = parentRoot[:]
 				blk.Block.Body.ExecutionPayload.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
 				blk.Block.Body.ExecutionPayload.FeeRecipient = bytesutil.PadTo([]byte{'a'}, fieldparams.FeeRecipientLength)
 				blk.Block.Body.ExecutionPayload.StateRoot = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
@@ -436,8 +485,59 @@ func Test_IsOptimisticCandidateBlock(t *testing.T) {
 				Root:  jroot[:],
 				Epoch: slots.ToEpoch(tt.justified.Block().Slot()),
 			})
+		require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wrappedParentBlock))
+
 		candidate, err := service.optimisticCandidateBlock(ctx, tt.blk)
 		require.NoError(t, err)
 		require.Equal(t, tt.want, candidate, tt.name)
 	}
 }
+
+func Test_IsOptimisticShallowExecutionParent(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	params.OverrideBeaconConfig(params.MainnetConfig())
+
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB)),
+	}
+
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+
+	params.BeaconConfig().SafeSlotsToImportOptimistically = 128
+	service.genesisTime = time.Now().Add(-time.Second * 12 * 2 * 128)
+	payload := &v1.ExecutionPayload{
+		ParentHash:    make([]byte, 32),
+		FeeRecipient:  make([]byte, 20),
+		StateRoot:     make([]byte, 32),
+		ReceiptsRoot:  make([]byte, 32),
+		LogsBloom:     make([]byte, 256),
+		PrevRandao:    make([]byte, 32),
+		BaseFeePerGas: bytesutil.PadTo([]byte{1, 2, 3, 4}, fieldparams.RootLength),
+		BlockHash:     make([]byte, 32),
+		BlockNumber:   100,
+	}
+	body := &ethpb.BeaconBlockBodyBellatrix{ExecutionPayload: payload}
+	block := &ethpb.BeaconBlockBellatrix{Body: body, Slot: 200}
+	rawSigned := &ethpb.SignedBeaconBlockBellatrix{Block: block}
+	blk := util.HydrateSignedBeaconBlockBellatrix(rawSigned)
+	wr, err := wrapper.WrappedBellatrixSignedBeaconBlock(blk)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wr))
+	blkRoot, err := wr.Block().HashTreeRoot()
+	require.NoError(t, err)
+
+	childBlock := util.NewBeaconBlockBellatrix()
+	childBlock.Block.ParentRoot = blkRoot[:]
+	// shallow block
+	childBlock.Block.Slot = 201
+	wrappedChild, err := wrapper.WrappedBellatrixSignedBeaconBlock(childBlock)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wrappedChild))
+	candidate, err := service.optimisticCandidateBlock(ctx, wrappedChild.Block())
+	require.NoError(t, err)
+	require.Equal(t, true, candidate)
+}

beacon-chain/blockchain/options.go

@@ -11,6 +11,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/voluntaryexits"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p"
 	"github.com/prysmaticlabs/prysm/beacon-chain/powchain"
+	enginev1 "github.com/prysmaticlabs/prysm/beacon-chain/powchain/engine-api-client/v1"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
@@ -50,6 +51,14 @@ func WithChainStartFetcher(f powchain.ChainStartFetcher) Option {
 	}
 }
 
+// WithExecutionEngineCaller to call execution engine.
+func WithExecutionEngineCaller(c enginev1.Caller) Option {
+	return func(s *Service) error {
+		s.cfg.ExecutionEngineCaller = c
+		return nil
+	}
+}
+
 // WithDepositCache for deposit lifecycle after chain inclusion.
 func WithDepositCache(c *depositcache.DepositCache) Option {
 	return func(s *Service) error {

beacon-chain/blockchain/process_attestation_test.go

@@ -8,6 +8,7 @@ import (
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/transition"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
+	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
 	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
@@ -21,7 +22,7 @@ import (
 	"github.com/prysmaticlabs/prysm/time/slots"
 )
 
-func TestStore_OnAttestation_ErrorConditions(t *testing.T) {
+func TestStore_OnAttestation_ErrorConditions_ProtoArray(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 
@@ -127,7 +128,113 @@ func TestStore_OnAttestation_ErrorConditions(t *testing.T) {
 	}
 }
 
-func TestStore_OnAttestation_Ok(t *testing.T) {
+func TestStore_OnAttestation_ErrorConditions_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithForkChoiceStore(doublylinkedtree.New(0, 0)),
+		WithStateGen(stategen.New(beaconDB)),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+
+	_, err = blockTree1(t, beaconDB, []byte{'g'})
+	require.NoError(t, err)
+
+	BlkWithOutState := util.NewBeaconBlock()
+	BlkWithOutState.Block.Slot = 0
+	require.NoError(t, beaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(BlkWithOutState)))
+	BlkWithOutStateRoot, err := BlkWithOutState.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	BlkWithStateBadAtt := util.NewBeaconBlock()
+	BlkWithStateBadAtt.Block.Slot = 1
+	require.NoError(t, beaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(BlkWithStateBadAtt)))
+	BlkWithStateBadAttRoot, err := BlkWithStateBadAtt.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	s, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, s.SetSlot(100*params.BeaconConfig().SlotsPerEpoch))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, BlkWithStateBadAttRoot))
+
+	BlkWithValidState := util.NewBeaconBlock()
+	BlkWithValidState.Block.Slot = 2
+	require.NoError(t, beaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(BlkWithValidState)))
+
+	BlkWithValidStateRoot, err := BlkWithValidState.Block.HashTreeRoot()
+	require.NoError(t, err)
+	s, err = util.NewBeaconState()
+	require.NoError(t, err)
+	err = s.SetFork(&ethpb.Fork{
+		Epoch:           0,
+		CurrentVersion:  params.BeaconConfig().GenesisForkVersion,
+		PreviousVersion: params.BeaconConfig().GenesisForkVersion,
+	})
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, s, BlkWithValidStateRoot))
+
+	tests := []struct {
+		name      string
+		a         *ethpb.Attestation
+		wantedErr string
+	}{
+		{
+			name:      "attestation's data slot not aligned with target vote",
+			a:         util.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Slot: params.BeaconConfig().SlotsPerEpoch, Target: &ethpb.Checkpoint{Root: make([]byte, 32)}}}),
+			wantedErr: "slot 32 does not match target epoch 0",
+		},
+		{
+			name:      "no pre state for attestations's target block",
+			a:         util.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Target: &ethpb.Checkpoint{Root: BlkWithOutStateRoot[:]}}}),
+			wantedErr: "could not get pre state for epoch 0",
+		},
+		{
+			name: "process attestation doesn't match current epoch",
+			a: util.HydrateAttestation(&ethpb.Attestation{Data: &ethpb.AttestationData{Slot: 100 * params.BeaconConfig().SlotsPerEpoch, Target: &ethpb.Checkpoint{Epoch: 100,
+				Root: BlkWithStateBadAttRoot[:]}}}),
+			wantedErr: "target epoch 100 does not match current epoch",
+		},
+		{
+			name:      "process nil attestation",
+			a:         nil,
+			wantedErr: "attestation can't be nil",
+		},
+		{
+			name:      "process nil field (a.Data) in attestation",
+			a:         &ethpb.Attestation{},
+			wantedErr: "attestation's data can't be nil",
+		},
+		{
+			name: "process nil field (a.Target) in attestation",
+			a: &ethpb.Attestation{
+				Data: &ethpb.AttestationData{
+					BeaconBlockRoot: make([]byte, fieldparams.RootLength),
+					Target:          nil,
+					Source:          &ethpb.Checkpoint{Root: make([]byte, fieldparams.RootLength)},
+				},
+				AggregationBits: make([]byte, 1),
+				Signature:       make([]byte, 96),
+			},
+			wantedErr: "attestation's target can't be nil",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := service.OnAttestation(ctx, tt.a)
+			if tt.wantedErr != "" {
+				assert.ErrorContains(t, tt.wantedErr, err)
+			} else {
+				assert.NoError(t, err)
+			}
+		})
+	}
+}
+
+func TestStore_OnAttestation_Ok_ProtoArray(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 
@@ -149,7 +256,33 @@ func TestStore_OnAttestation_Ok(t *testing.T) {
 	copied, err = transition.ProcessSlots(ctx, copied, 1)
 	require.NoError(t, err)
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, copied, tRoot))
-	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(ctx, 0, tRoot, tRoot, tRoot, 1, 1))
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 0, tRoot, tRoot, 1, 1))
+	require.NoError(t, service.OnAttestation(ctx, att[0]))
+}
+
+func TestStore_OnAttestation_Ok_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	fcs := doublylinkedtree.New(0, 0)
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB)),
+		WithForkChoiceStore(fcs),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	genesisState, pks := util.DeterministicGenesisState(t, 64)
+	service.SetGenesisTime(time.Unix(time.Now().Unix()-int64(params.BeaconConfig().SecondsPerSlot), 0))
+	require.NoError(t, service.saveGenesisData(ctx, genesisState))
+	att, err := util.GenerateAttestations(genesisState, pks, 1, 0, false)
+	require.NoError(t, err)
+	tRoot := bytesutil.ToBytes32(att[0].Data.Target.Root)
+	copied := genesisState.Copy()
+	copied, err = transition.ProcessSlots(ctx, copied, 1)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, copied, tRoot))
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 0, tRoot, tRoot, 1, 1))
 	require.NoError(t, service.OnAttestation(ctx, att[0]))
 }
 
@@ -330,7 +463,7 @@ func TestVerifyBeaconBlock_OK(t *testing.T) {
 	assert.NoError(t, service.verifyBeaconBlock(ctx, d), "Did not receive the wanted error")
 }
 
-func TestVerifyFinalizedConsistency_InconsistentRoot(t *testing.T) {
+func TestVerifyFinalizedConsistency_InconsistentRoot_ProtoArray(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 
@@ -361,6 +494,37 @@ func TestVerifyFinalizedConsistency_InconsistentRoot(t *testing.T) {
 	require.ErrorContains(t, "Root and finalized store are not consistent", err)
 }
 
+func TestVerifyFinalizedConsistency_InconsistentRoot_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	fcs := doublylinkedtree.New(0, 0)
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB)),
+		WithForkChoiceStore(fcs),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+
+	b32 := util.NewBeaconBlock()
+	b32.Block.Slot = 32
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(b32)))
+	r32, err := b32.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Epoch: 1})
+	b33 := util.NewBeaconBlock()
+	b33.Block.Slot = 33
+	b33.Block.ParentRoot = r32[:]
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(b33)))
+	r33, err := b33.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	err = service.VerifyFinalizedConsistency(context.Background(), r33[:])
+	require.ErrorContains(t, "Root and finalized store are not consistent", err)
+}
+
 func TestVerifyFinalizedConsistency_OK(t *testing.T) {
 	ctx := context.Background()
 
@@ -407,8 +571,8 @@ func TestVerifyFinalizedConsistency_IsCanonical(t *testing.T) {
 	r33, err := b33.Block.HashTreeRoot()
 	require.NoError(t, err)
 
-	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(ctx, b32.Block.Slot, r32, [32]byte{}, [32]byte{}, 0, 0))
-	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(ctx, b33.Block.Slot, r33, r32, [32]byte{}, 0, 0))
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, b32.Block.Slot, r32, [32]byte{}, 0, 0))
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, b33.Block.Slot, r33, r32, 0, 0))
 
 	_, err = service.cfg.ForkChoiceStore.Head(ctx, 0, r32, []uint64{}, 0)
 	require.NoError(t, err)

beacon-chain/blockchain/process_block.go

@@ -21,6 +21,7 @@ import (
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/attestation"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
+	"github.com/prysmaticlabs/prysm/runtime/version"
 	"github.com/prysmaticlabs/prysm/time/slots"
 	"go.opencensus.io/trace"
 )
@@ -98,11 +99,21 @@ func (s *Service) onBlock(ctx context.Context, signed block.SignedBeaconBlock, b
 		return err
 	}
 
+	preStateVersion, preStateHeader, err := getStateVersionAndPayload(preState)
+	if err != nil {
+		return err
+	}
 	postState, err := transition.ExecuteStateTransition(ctx, preState, signed)
 	if err != nil {
 		return err
 	}
+	if err := s.notifyNewPayload(ctx, preStateVersion, preStateHeader, postState, signed); err != nil {
+		return errors.Wrap(err, "could not verify new payload")
+	}
 
+	if err := s.savePostStateInfo(ctx, blockRoot, signed, postState, false /* reg sync */); err != nil {
+		return err
+	}
 	// We add a proposer score boost to fork choice for the block root if applicable, right after
 	// running a successful state transition for the block.
 	if err := s.cfg.ForkChoiceStore.BoostProposerRoot(
@@ -111,10 +122,6 @@ func (s *Service) onBlock(ctx context.Context, signed block.SignedBeaconBlock, b
 		return err
 	}
 
-	if err := s.savePostStateInfo(ctx, blockRoot, signed, postState, false /* reg sync */); err != nil {
-		return err
-	}
-
 	// If slasher is configured, forward the attestations in the block via
 	// an event feed for processing.
 	if features.Get().EnableSlasher {
@@ -174,9 +181,8 @@ func (s *Service) onBlock(ctx context.Context, signed block.SignedBeaconBlock, b
 	if err := s.updateHead(ctx, balances); err != nil {
 		log.WithError(err).Warn("Could not update head")
 	}
-
-	if err := s.saveSyncedTipsDB(ctx); err != nil {
-		return errors.Wrap(err, "could not save synced tips")
+	if _, err := s.notifyForkchoiceUpdate(ctx, s.headBlock().Block(), s.headRoot(), bytesutil.ToBytes32(finalized.Root)); err != nil {
+		return err
 	}
 
 	if err := s.pruneCanonicalAttsFromPool(ctx, blockRoot, signed); err != nil {
@@ -250,6 +256,21 @@ func (s *Service) onBlock(ctx context.Context, signed block.SignedBeaconBlock, b
 	return s.handleEpochBoundary(ctx, postState)
 }
 
+func getStateVersionAndPayload(preState state.BeaconState) (int, *ethpb.ExecutionPayloadHeader, error) {
+	var preStateHeader *ethpb.ExecutionPayloadHeader
+	var err error
+	preStateVersion := preState.Version()
+	switch preStateVersion {
+	case version.Phase0, version.Altair:
+	default:
+		preStateHeader, err = preState.LatestExecutionPayloadHeader()
+		if err != nil {
+			return 0, nil, err
+		}
+	}
+	return preStateVersion, preStateHeader, nil
+}
+
 func (s *Service) onBlockBatch(ctx context.Context, blks []block.SignedBeaconBlock,
 	blockRoots [][32]byte) ([]*ethpb.Checkpoint, []*ethpb.Checkpoint, error) {
 	ctx, span := trace.StartSpan(ctx, "blockChain.onBlockBatch")
@@ -285,10 +306,18 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []block.SignedBeaconBlo
 	var set *bls.SignatureBatch
 	boundaries := make(map[[32]byte]state.BeaconState)
 	for i, b := range blks {
+		preStateVersion, preStateHeader, err := getStateVersionAndPayload(preState)
+		if err != nil {
+			return nil, nil, err
+		}
 		set, preState, err = transition.ExecuteStateTransitionNoVerifyAnySig(ctx, preState, b)
 		if err != nil {
 			return nil, nil, err
 		}
+		if err := s.notifyNewPayload(ctx, preStateVersion, preStateHeader, preState, b); err != nil {
+			return nil, nil, err
+		}
+
 		// Save potential boundary states.
 		if slots.IsEpochStart(preState.Slot()) {
 			boundaries[blockRoots[i]] = preState.Copy()
@@ -298,6 +327,7 @@ func (s *Service) onBlockBatch(ctx context.Context, blks []block.SignedBeaconBlo
 		}
 		jCheckpoints[i] = preState.CurrentJustifiedCheckpoint()
 		fCheckpoints[i] = preState.FinalizedCheckpoint()
+
 		sigSet.Join(set)
 	}
 	verify, err := sigSet.Verify()
@@ -334,8 +364,8 @@ func (s *Service) handleBlockAfterBatchVerify(ctx context.Context, signed block.
 	if err := s.insertBlockToForkChoiceStore(ctx, b, blockRoot, fCheckpoint, jCheckpoint); err != nil {
 		return err
 	}
-	if err := s.saveSyncedTipsDB(ctx); err != nil {
-		return errors.Wrap(err, "could not save synced tips")
+	if _, err := s.notifyForkchoiceUpdate(ctx, b, blockRoot, bytesutil.ToBytes32(fCheckpoint.Root)); err != nil {
+		return err
 	}
 
 	if err := s.cfg.BeaconDB.SaveStateSummary(ctx, &ethpb.StateSummary{
@@ -452,13 +482,10 @@ func (s *Service) insertBlockToForkChoiceStore(ctx context.Context, blk block.Be
 		return err
 	}
 	// Feed in block to fork choice store.
-	if err := s.cfg.ForkChoiceStore.ProcessBlock(ctx,
-		blk.Slot(), root, bytesutil.ToBytes32(blk.ParentRoot()), bytesutil.ToBytes32(blk.Body().Graffiti()),
+	return s.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx,
+		blk.Slot(), root, bytesutil.ToBytes32(blk.ParentRoot()),
 		jCheckpoint.Epoch,
-		fCheckpoint.Epoch); err != nil {
-		return errors.Wrap(err, "could not process block for proto array fork choice")
-	}
-	return nil
+		fCheckpoint.Epoch)
 }
 
 // This saves post state info to DB or cache. This also saves post state info to fork choice store.
@@ -509,12 +536,3 @@ func (s *Service) pruneCanonicalAttsFromPool(ctx context.Context, r [32]byte, b
 	}
 	return nil
 }
-
-// Saves synced and validated tips to DB.
-func (s *Service) saveSyncedTipsDB(ctx context.Context) error {
-	tips := s.cfg.ForkChoiceStore.SyncedTips()
-	if len(tips) == 0 {
-		return nil
-	}
-	return s.cfg.BeaconDB.UpdateValidatedTips(ctx, tips)
-}

beacon-chain/blockchain/process_block_helpers.go

@@ -366,14 +366,13 @@ func (s *Service) fillInForkChoiceMissingBlocks(ctx context.Context, blk block.B
 	for i := len(pendingNodes) - 1; i >= 0; i-- {
 		b := pendingNodes[i]
 		r := pendingRoots[i]
-		if err := s.cfg.ForkChoiceStore.ProcessBlock(ctx,
-			b.Slot(), r, bytesutil.ToBytes32(b.ParentRoot()), bytesutil.ToBytes32(b.Body().Graffiti()),
+		if err := s.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx,
+			b.Slot(), r, bytesutil.ToBytes32(b.ParentRoot()),
 			jCheckpoint.Epoch,
 			fCheckpoint.Epoch); err != nil {
 			return errors.Wrap(err, "could not process block for proto array fork choice")
 		}
 	}
-
 	return nil
 }
 

beacon-chain/blockchain/process_block_test.go

@@ -16,6 +16,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/transition"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
+	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
@@ -27,13 +28,14 @@ import (
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/block"
 	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
+	"github.com/prysmaticlabs/prysm/runtime/version"
 	"github.com/prysmaticlabs/prysm/testing/assert"
 	"github.com/prysmaticlabs/prysm/testing/require"
 	"github.com/prysmaticlabs/prysm/testing/util"
 	prysmTime "github.com/prysmaticlabs/prysm/time"
 )
 
-func TestStore_OnBlock(t *testing.T) {
+func TestStore_OnBlock_ProtoArray(t *testing.T) {
 	ctx := context.Background()
 
 	beaconDB := testDB.SetupDB(t)
@@ -130,7 +132,122 @@ func TestStore_OnBlock(t *testing.T) {
 	}
 }
 
-func TestStore_OnBlockBatch(t *testing.T) {
+func TestStore_OnBlock_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+
+	beaconDB := testDB.SetupDB(t)
+	fcs := doublylinkedtree.New(0, 0)
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB)),
+		WithForkChoiceStore(fcs),
+	}
+
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	genesisStateRoot := [32]byte{}
+	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
+	assert.NoError(t, beaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(genesis)))
+	validGenesisRoot, err := genesis.Block.HashTreeRoot()
+	require.NoError(t, err)
+	st, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))
+	roots, err := blockTree1(t, beaconDB, validGenesisRoot[:])
+	require.NoError(t, err)
+	random := util.NewBeaconBlock()
+	random.Block.Slot = 1
+	random.Block.ParentRoot = validGenesisRoot[:]
+	assert.NoError(t, beaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(random)))
+	randomParentRoot, err := random.Block.HashTreeRoot()
+	assert.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &ethpb.StateSummary{Slot: st.Slot(), Root: randomParentRoot[:]}))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), randomParentRoot))
+	randomParentRoot2 := roots[1]
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &ethpb.StateSummary{Slot: st.Slot(), Root: randomParentRoot2}))
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), bytesutil.ToBytes32(randomParentRoot2)))
+
+	tests := []struct {
+		name          string
+		blk           *ethpb.SignedBeaconBlock
+		s             state.BeaconState
+		time          uint64
+		wantErrString string
+	}{
+		{
+			name:          "parent block root does not have a state",
+			blk:           util.NewBeaconBlock(),
+			s:             st.Copy(),
+			wantErrString: "could not reconstruct parent state",
+		},
+		{
+			name: "block is from the future",
+			blk: func() *ethpb.SignedBeaconBlock {
+				b := util.NewBeaconBlock()
+				b.Block.ParentRoot = randomParentRoot2
+				b.Block.Slot = params.BeaconConfig().FarFutureSlot
+				return b
+			}(),
+			s:             st.Copy(),
+			wantErrString: "is in the far distant future",
+		},
+		{
+			name: "could not get finalized block",
+			blk: func() *ethpb.SignedBeaconBlock {
+				b := util.NewBeaconBlock()
+				b.Block.ParentRoot = randomParentRoot[:]
+				return b
+			}(),
+			s:             st.Copy(),
+			wantErrString: "is not a descendant of the current finalized block",
+		},
+		{
+			name: "same slot as finalized block",
+			blk: func() *ethpb.SignedBeaconBlock {
+				b := util.NewBeaconBlock()
+				b.Block.Slot = 0
+				b.Block.ParentRoot = randomParentRoot2
+				return b
+			}(),
+			s:             st.Copy(),
+			wantErrString: "block is equal or earlier than finalized block, slot 0 < slot 0",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			service.store.SetJustifiedCheckpt(&ethpb.Checkpoint{Root: validGenesisRoot[:]})
+			service.store.SetBestJustifiedCheckpt(&ethpb.Checkpoint{Root: validGenesisRoot[:]})
+			service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: roots[0]})
+			service.store.SetPrevFinalizedCheckpt(&ethpb.Checkpoint{Root: validGenesisRoot[:]})
+
+			root, err := tt.blk.Block.HashTreeRoot()
+			assert.NoError(t, err)
+			err = service.onBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(tt.blk), root)
+			assert.ErrorContains(t, tt.wantErrString, err)
+		})
+	}
+}
+
+func TestStore_OnBlock_ProposerBoostEarly(t *testing.T) {
+	ctx := context.Background()
+
+	beaconDB := testDB.SetupDB(t)
+	fcs := doublylinkedtree.New(0, 0)
+	opts := []Option{
+		WithStateGen(stategen.New(beaconDB)),
+		WithForkChoiceStore(fcs),
+	}
+
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.ForkChoiceStore.BoostProposerRoot(ctx, 0, [32]byte{'A'}, time.Now()))
+	_, err = service.cfg.ForkChoiceStore.Head(ctx, 0,
+		params.BeaconConfig().ZeroHash, []uint64{}, 0)
+	require.ErrorContains(t, "could not apply proposer boost score: invalid proposer boost root", err)
+}
+
+func TestStore_OnBlockBatch_ProtoArray(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 
@@ -182,6 +299,58 @@ func TestStore_OnBlockBatch(t *testing.T) {
 	require.NoError(t, err)
 }
 
+func TestStore_OnBlockBatch_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB)),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+
+	genesisStateRoot := [32]byte{}
+	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
+	assert.NoError(t, beaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(genesis)))
+	gRoot, err := genesis.Block.HashTreeRoot()
+	require.NoError(t, err)
+	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: gRoot[:]})
+
+	service.cfg.ForkChoiceStore = doublylinkedtree.New(0, 0)
+	service.saveInitSyncBlock(gRoot, wrapper.WrappedPhase0SignedBeaconBlock(genesis))
+
+	st, keys := util.DeterministicGenesisState(t, 64)
+
+	bState := st.Copy()
+
+	var blks []block.SignedBeaconBlock
+	var blkRoots [][32]byte
+	var firstState state.BeaconState
+	for i := 1; i < 10; i++ {
+		b, err := util.GenerateFullBlock(bState, keys, util.DefaultBlockGenConfig(), types.Slot(i))
+		require.NoError(t, err)
+		bState, err = transition.ExecuteStateTransition(ctx, bState, wrapper.WrappedPhase0SignedBeaconBlock(b))
+		require.NoError(t, err)
+		if i == 1 {
+			firstState = bState.Copy()
+		}
+		root, err := b.Block.HashTreeRoot()
+		require.NoError(t, err)
+		service.saveInitSyncBlock(root, wrapper.WrappedPhase0SignedBeaconBlock(b))
+		blks = append(blks, wrapper.WrappedPhase0SignedBeaconBlock(b))
+		blkRoots = append(blkRoots, root)
+	}
+
+	rBlock, err := blks[0].PbPhase0Block()
+	assert.NoError(t, err)
+	rBlock.Block.ParentRoot = gRoot[:]
+	require.NoError(t, beaconDB.SaveBlock(context.Background(), blks[0]))
+	require.NoError(t, service.cfg.StateGen.SaveState(ctx, blkRoots[0], firstState))
+	_, _, err = service.onBlockBatch(ctx, blks[1:], blkRoots[1:])
+	require.NoError(t, err)
+}
+
 func TestRemoveStateSinceLastFinalized_EmptyStartSlot(t *testing.T) {
 	ctx := context.Background()
 	params.SetupTestConfigCleanup(t)
@@ -215,7 +384,7 @@ func TestRemoveStateSinceLastFinalized_EmptyStartSlot(t *testing.T) {
 	assert.Equal(t, true, update, "Should be able to update justified")
 }
 
-func TestShouldUpdateJustified_ReturnFalse(t *testing.T) {
+func TestShouldUpdateJustified_ReturnFalse_ProtoArray(t *testing.T) {
 	ctx := context.Background()
 	params.SetupTestConfigCleanup(t)
 	params.OverrideBeaconConfig(params.MinimalSpecConfig())
@@ -244,7 +413,36 @@ func TestShouldUpdateJustified_ReturnFalse(t *testing.T) {
 	assert.Equal(t, false, update, "Should not be able to update justified, received true")
 }
 
-func TestCachedPreState_CanGetFromStateSummary(t *testing.T) {
+func TestShouldUpdateJustified_ReturnFalse_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+	params.SetupTestConfigCleanup(t)
+	params.OverrideBeaconConfig(params.MinimalSpecConfig())
+
+	opts := testServiceOptsWithDB(t)
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	service.cfg.ForkChoiceStore = doublylinkedtree.New(0, 0)
+	lastJustifiedBlk := util.NewBeaconBlock()
+	lastJustifiedBlk.Block.ParentRoot = bytesutil.PadTo([]byte{'G'}, 32)
+	lastJustifiedRoot, err := lastJustifiedBlk.Block.HashTreeRoot()
+	require.NoError(t, err)
+	newJustifiedBlk := util.NewBeaconBlock()
+	newJustifiedBlk.Block.ParentRoot = bytesutil.PadTo(lastJustifiedRoot[:], 32)
+	newJustifiedRoot, err := newJustifiedBlk.Block.HashTreeRoot()
+	require.NoError(t, err)
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(newJustifiedBlk)))
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(lastJustifiedBlk)))
+
+	diff := params.BeaconConfig().SlotsPerEpoch.Sub(1).Mul(params.BeaconConfig().SecondsPerSlot)
+	service.genesisTime = time.Unix(time.Now().Unix()-int64(diff), 0)
+	service.store.SetJustifiedCheckpt(&ethpb.Checkpoint{Root: lastJustifiedRoot[:]})
+
+	update, err := service.shouldUpdateCurrentJustified(ctx, &ethpb.Checkpoint{Root: newJustifiedRoot[:]})
+	require.NoError(t, err)
+	assert.Equal(t, false, update, "Should not be able to update justified, received true")
+}
+
+func TestCachedPreState_CanGetFromStateSummary_ProtoArray(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 
@@ -275,6 +473,37 @@ func TestCachedPreState_CanGetFromStateSummary(t *testing.T) {
 	require.NoError(t, service.verifyBlkPreState(ctx, wrapper.WrappedPhase0BeaconBlock(b.Block)))
 }
 
+func TestCachedPreState_CanGetFromStateSummary_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB)),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+
+	s, err := v1.InitializeFromProto(&ethpb.BeaconState{Slot: 1, GenesisValidatorsRoot: params.BeaconConfig().ZeroHash[:]})
+	require.NoError(t, err)
+
+	genesisStateRoot := [32]byte{}
+	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
+	assert.NoError(t, beaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(genesis)))
+	gRoot, err := genesis.Block.HashTreeRoot()
+	require.NoError(t, err)
+	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: gRoot[:]})
+	service.cfg.ForkChoiceStore = doublylinkedtree.New(0, 0)
+	service.saveInitSyncBlock(gRoot, wrapper.WrappedPhase0SignedBeaconBlock(genesis))
+
+	b := util.NewBeaconBlock()
+	b.Block.Slot = 1
+	b.Block.ParentRoot = gRoot[:]
+	require.NoError(t, service.cfg.BeaconDB.SaveStateSummary(ctx, &ethpb.StateSummary{Slot: 1, Root: gRoot[:]}))
+	require.NoError(t, service.cfg.StateGen.SaveState(ctx, gRoot, s))
+	require.NoError(t, service.verifyBlkPreState(ctx, wrapper.WrappedPhase0BeaconBlock(b.Block)))
+}
+
 func TestCachedPreState_CanGetFromDB(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
@@ -347,7 +576,7 @@ func TestUpdateJustified_CouldUpdateBest(t *testing.T) {
 	assert.Equal(t, types.Epoch(2), service.store.BestJustifiedCheckpt().Epoch, "Incorrect justified epoch in service")
 }
 
-func TestFillForkChoiceMissingBlocks_CanSave(t *testing.T) {
+func TestFillForkChoiceMissingBlocks_CanSave_ProtoArray(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 
@@ -382,13 +611,54 @@ func TestFillForkChoiceMissingBlocks_CanSave(t *testing.T) {
 	require.NoError(t, err)
 
 	// 5 nodes from the block tree 1. B0 - B3 - B4 - B6 - B8
-	assert.Equal(t, 5, len(service.cfg.ForkChoiceStore.Nodes()), "Miss match nodes")
+	assert.Equal(t, 5, service.cfg.ForkChoiceStore.NodeCount(), "Miss match nodes")
 	assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(bytesutil.ToBytes32(roots[4])), "Didn't save node")
 	assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(bytesutil.ToBytes32(roots[6])), "Didn't save node")
 	assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(bytesutil.ToBytes32(roots[8])), "Didn't save node")
 }
 
-func TestFillForkChoiceMissingBlocks_RootsMatch(t *testing.T) {
+func TestFillForkChoiceMissingBlocks_CanSave_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB)),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	service.cfg.ForkChoiceStore = doublylinkedtree.New(0, 0)
+	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: make([]byte, 32)})
+
+	genesisStateRoot := [32]byte{}
+	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
+	require.NoError(t, beaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(genesis)))
+	validGenesisRoot, err := genesis.Block.HashTreeRoot()
+	require.NoError(t, err)
+	st, err := util.NewBeaconState()
+	require.NoError(t, err)
+
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))
+	roots, err := blockTree1(t, beaconDB, validGenesisRoot[:])
+	require.NoError(t, err)
+
+	beaconState, _ := util.DeterministicGenesisState(t, 32)
+	block := util.NewBeaconBlock()
+	block.Block.Slot = 9
+	block.Block.ParentRoot = roots[8]
+
+	err = service.fillInForkChoiceMissingBlocks(
+		context.Background(), wrapper.WrappedPhase0SignedBeaconBlock(block).Block(), beaconState.FinalizedCheckpoint(), beaconState.CurrentJustifiedCheckpoint())
+	require.NoError(t, err)
+
+	// 5 nodes from the block tree 1. B0 - B3 - B4 - B6 - B8
+	assert.Equal(t, 5, service.cfg.ForkChoiceStore.NodeCount(), "Miss match nodes")
+	assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(bytesutil.ToBytes32(roots[4])), "Didn't save node")
+	assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(bytesutil.ToBytes32(roots[6])), "Didn't save node")
+	assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(bytesutil.ToBytes32(roots[8])), "Didn't save node")
+}
+
+func TestFillForkChoiceMissingBlocks_RootsMatch_ProtoArray(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 
@@ -423,7 +693,7 @@ func TestFillForkChoiceMissingBlocks_RootsMatch(t *testing.T) {
 	require.NoError(t, err)
 
 	// 5 nodes from the block tree 1. B0 - B3 - B4 - B6 - B8
-	assert.Equal(t, 5, len(service.cfg.ForkChoiceStore.Nodes()), "Miss match nodes")
+	assert.Equal(t, 5, service.cfg.ForkChoiceStore.NodeCount(), "Miss match nodes")
 	// Ensure all roots and their respective blocks exist.
 	wantedRoots := [][]byte{roots[0], roots[3], roots[4], roots[6], roots[8]}
 	for i, rt := range wantedRoots {
@@ -432,7 +702,51 @@ func TestFillForkChoiceMissingBlocks_RootsMatch(t *testing.T) {
 	}
 }
 
-func TestFillForkChoiceMissingBlocks_FilterFinalized(t *testing.T) {
+func TestFillForkChoiceMissingBlocks_RootsMatch_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB)),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	service.cfg.ForkChoiceStore = doublylinkedtree.New(0, 0)
+	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: make([]byte, 32)})
+
+	genesisStateRoot := [32]byte{}
+	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
+	require.NoError(t, beaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(genesis)))
+	validGenesisRoot, err := genesis.Block.HashTreeRoot()
+	require.NoError(t, err)
+	st, err := util.NewBeaconState()
+	require.NoError(t, err)
+
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))
+	roots, err := blockTree1(t, beaconDB, validGenesisRoot[:])
+	require.NoError(t, err)
+
+	beaconState, _ := util.DeterministicGenesisState(t, 32)
+	block := util.NewBeaconBlock()
+	block.Block.Slot = 9
+	block.Block.ParentRoot = roots[8]
+
+	err = service.fillInForkChoiceMissingBlocks(
+		context.Background(), wrapper.WrappedPhase0SignedBeaconBlock(block).Block(), beaconState.FinalizedCheckpoint(), beaconState.CurrentJustifiedCheckpoint())
+	require.NoError(t, err)
+
+	// 5 nodes from the block tree 1. B0 - B3 - B4 - B6 - B8
+	assert.Equal(t, 5, service.cfg.ForkChoiceStore.NodeCount(), "Miss match nodes")
+	// Ensure all roots and their respective blocks exist.
+	wantedRoots := [][]byte{roots[0], roots[3], roots[4], roots[6], roots[8]}
+	for i, rt := range wantedRoots {
+		assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(bytesutil.ToBytes32(rt)), fmt.Sprintf("Didn't save node: %d", i))
+		assert.Equal(t, true, service.cfg.BeaconDB.HasBlock(context.Background(), bytesutil.ToBytes32(rt)))
+	}
+}
+
+func TestFillForkChoiceMissingBlocks_FilterFinalized_ProtoArray(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 
@@ -479,7 +793,60 @@ func TestFillForkChoiceMissingBlocks_FilterFinalized(t *testing.T) {
 	require.NoError(t, err)
 
 	// There should be 2 nodes, block 65 and block 64.
-	assert.Equal(t, 2, len(service.cfg.ForkChoiceStore.Nodes()), "Miss match nodes")
+	assert.Equal(t, 2, service.cfg.ForkChoiceStore.NodeCount(), "Miss match nodes")
+
+	// Block with slot 63 should be in fork choice because it's less than finalized epoch 1.
+	assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(r63), "Didn't save node")
+}
+
+func TestFillForkChoiceMissingBlocks_FilterFinalized_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB)),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+	service.cfg.ForkChoiceStore = doublylinkedtree.New(0, 0)
+	// Set finalized epoch to 1.
+	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Epoch: 1})
+
+	genesisStateRoot := [32]byte{}
+	genesis := blocks.NewGenesisBlock(genesisStateRoot[:])
+	assert.NoError(t, beaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(genesis)))
+	validGenesisRoot, err := genesis.Block.HashTreeRoot()
+	assert.NoError(t, err)
+	st, err := util.NewBeaconState()
+	require.NoError(t, err)
+
+	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, st.Copy(), validGenesisRoot))
+
+	// Define a tree branch, slot 63 <- 64 <- 65
+	b63 := util.NewBeaconBlock()
+	b63.Block.Slot = 63
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(b63)))
+	r63, err := b63.Block.HashTreeRoot()
+	require.NoError(t, err)
+	b64 := util.NewBeaconBlock()
+	b64.Block.Slot = 64
+	b64.Block.ParentRoot = r63[:]
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(b64)))
+	r64, err := b64.Block.HashTreeRoot()
+	require.NoError(t, err)
+	b65 := util.NewBeaconBlock()
+	b65.Block.Slot = 65
+	b65.Block.ParentRoot = r64[:]
+	require.NoError(t, service.cfg.BeaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(b65)))
+
+	beaconState, _ := util.DeterministicGenesisState(t, 32)
+	err = service.fillInForkChoiceMissingBlocks(
+		context.Background(), wrapper.WrappedPhase0SignedBeaconBlock(b65).Block(), beaconState.FinalizedCheckpoint(), beaconState.CurrentJustifiedCheckpoint())
+	require.NoError(t, err)
+
+	// There should be 2 nodes, block 65 and block 64.
+	assert.Equal(t, 2, service.cfg.ForkChoiceStore.NodeCount(), "Miss match nodes")
 
 	// Block with slot 63 should be in fork choice because it's less than finalized epoch 1.
 	assert.Equal(t, true, service.cfg.ForkChoiceStore.HasNode(r63), "Didn't save node")
@@ -668,7 +1035,7 @@ func TestAncestor_CanUseForkchoice(t *testing.T) {
 		beaconBlock.Block.ParentRoot = bytesutil.PadTo(b.Block.ParentRoot, 32)
 		r, err := b.Block.HashTreeRoot()
 		require.NoError(t, err)
-		require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(context.Background(), b.Block.Slot, r, bytesutil.ToBytes32(b.Block.ParentRoot), [32]byte{}, 0, 0)) // Saves blocks to fork choice store.
+		require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(context.Background(), b.Block.Slot, r, bytesutil.ToBytes32(b.Block.ParentRoot), 0, 0)) // Saves blocks to fork choice store.
 	}
 
 	r, err := service.ancestor(context.Background(), r200[:], 150)
@@ -713,7 +1080,7 @@ func TestAncestor_CanUseDB(t *testing.T) {
 		require.NoError(t, beaconDB.SaveBlock(context.Background(), wrapper.WrappedPhase0SignedBeaconBlock(beaconBlock))) // Saves blocks to DB.
 	}
 
-	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(context.Background(), 200, r200, r200, [32]byte{}, 0, 0))
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(context.Background(), 200, r200, r200, 0, 0))
 
 	r, err := service.ancestor(context.Background(), r200[:], 150)
 	require.NoError(t, err)
@@ -913,6 +1280,48 @@ func TestOnBlock_CanFinalize(t *testing.T) {
 	require.Equal(t, f.Epoch, service.FinalizedCheckpt().Epoch)
 }
 
+func TestOnBlock_CallNewPayloadAndForkchoiceUpdated(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	config := params.BeaconConfig()
+	config.AltairForkEpoch = 1
+	config.BellatrixForkEpoch = 2
+	params.OverrideBeaconConfig(config)
+
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	fcs := protoarray.New(0, 0, [32]byte{'a'})
+	depositCache, err := depositcache.New()
+	require.NoError(t, err)
+	opts := []Option{
+		WithDatabase(beaconDB),
+		WithStateGen(stategen.New(beaconDB)),
+		WithForkChoiceStore(fcs),
+		WithDepositCache(depositCache),
+		WithStateNotifier(&mock.MockStateNotifier{}),
+	}
+	service, err := NewService(ctx, opts...)
+	require.NoError(t, err)
+
+	gs, keys := util.DeterministicGenesisState(t, 32)
+	require.NoError(t, service.saveGenesisData(ctx, gs))
+	gBlk, err := service.cfg.BeaconDB.GenesisBlock(ctx)
+	require.NoError(t, err)
+	gRoot, err := gBlk.Block().HashTreeRoot()
+	require.NoError(t, err)
+	service.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Root: gRoot[:]})
+
+	testState := gs.Copy()
+	for i := types.Slot(1); i < params.BeaconConfig().SlotsPerEpoch; i++ {
+		blk, err := util.GenerateFullBlock(testState, keys, util.DefaultBlockGenConfig(), i)
+		require.NoError(t, err)
+		r, err := blk.Block.HashTreeRoot()
+		require.NoError(t, err)
+		require.NoError(t, service.onBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(blk), r))
+		testState, err = service.cfg.StateGen.StateByRoot(ctx, r)
+		require.NoError(t, err)
+	}
+}
+
 func TestInsertFinalizedDeposits(t *testing.T) {
 	ctx := context.Background()
 	opts := testServiceOptsWithDB(t)
@@ -997,48 +1406,52 @@ func TestRemoveBlockAttestationsInPool_NonCanonical(t *testing.T) {
 	require.Equal(t, 1, service.cfg.AttPool.AggregatedAttestationCount())
 }
 
-func TestService_saveSyncedTipsDB(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-	service := setupBeaconChain(t, beaconDB)
-
-	b1 := util.NewBeaconBlock()
-	b1.Block.Slot = 1
-	b1.Block.ParentRoot = bytesutil.PadTo([]byte{'a'}, 32)
-	r1, err := b1.Block.HashTreeRoot()
-	require.NoError(t, err)
-	b100 := util.NewBeaconBlock()
-	b100.Block.Slot = 100
-	b100.Block.ParentRoot = r1[:]
-	r100, err := b100.Block.HashTreeRoot()
-	require.NoError(t, err)
-	b200 := util.NewBeaconBlock()
-	b200.Block.Slot = 200
-	b200.Block.ParentRoot = r1[:]
-	r200, err := b200.Block.HashTreeRoot()
-	require.NoError(t, err)
-	for _, b := range []*ethpb.SignedBeaconBlock{b1, b100, b200} {
-		beaconBlock := util.NewBeaconBlock()
-		beaconBlock.Block.Slot = b.Block.Slot
-		beaconBlock.Block.ParentRoot = bytesutil.PadTo(b.Block.ParentRoot, 32)
-		r, err := b.Block.HashTreeRoot()
-		require.NoError(t, err)
-		require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(context.Background(), b.Block.Slot, r, bytesutil.ToBytes32(b.Block.ParentRoot), [32]byte{}, 0, 0))
+func Test_getStateVersionAndPayload(t *testing.T) {
+	tests := []struct {
+		name    string
+		st      state.BeaconState
+		version int
+		header  *ethpb.ExecutionPayloadHeader
+	}{
+		{
+			name: "phase 0 state",
+			st: func() state.BeaconState {
+				s, _ := util.DeterministicGenesisState(t, 1)
+				return s
+			}(),
+			version: version.Phase0,
+			header:  (*ethpb.ExecutionPayloadHeader)(nil),
+		},
+		{
+			name: "altair state",
+			st: func() state.BeaconState {
+				s, _ := util.DeterministicGenesisStateAltair(t, 1)
+				return s
+			}(),
+			version: version.Altair,
+			header:  (*ethpb.ExecutionPayloadHeader)(nil),
+		},
+		{
+			name: "bellatrix state",
+			st: func() state.BeaconState {
+				s, _ := util.DeterministicGenesisStateBellatrix(t, 1)
+				require.NoError(t, s.SetLatestExecutionPayloadHeader(&ethpb.ExecutionPayloadHeader{
+					BlockNumber: 1,
+				}))
+				return s
+			}(),
+			version: version.Bellatrix,
+			header: &ethpb.ExecutionPayloadHeader{
+				BlockNumber: 1,
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			version, header, err := getStateVersionAndPayload(tt.st)
+			require.NoError(t, err)
+			require.Equal(t, tt.version, version)
+			require.DeepEqual(t, tt.header, header)
+		})
 	}
-
-	require.NoError(t, service.cfg.ForkChoiceStore.UpdateSyncedTipsWithValidRoot(ctx, r100))
-	require.NoError(t, service.saveSyncedTipsDB(ctx))
-	savedTips, err := service.cfg.BeaconDB.ValidatedTips(ctx)
-	require.NoError(t, err)
-	require.Equal(t, 2, len(savedTips))
-	require.Equal(t, types.Slot(1), savedTips[r1])
-	require.Equal(t, types.Slot(100), savedTips[r100])
-
-	// Delete invalid root
-	require.NoError(t, service.cfg.ForkChoiceStore.UpdateSyncedTipsWithInvalidRoot(ctx, r200))
-	require.NoError(t, service.saveSyncedTipsDB(ctx))
-	savedTips, err = service.cfg.BeaconDB.ValidatedTips(ctx)
-	require.NoError(t, err)
-	require.Equal(t, 1, len(savedTips))
-	require.Equal(t, types.Slot(100), savedTips[r100])
 }

beacon-chain/blockchain/receive_attestation_test.go

@@ -111,7 +111,7 @@ func TestProcessAttestations_Ok(t *testing.T) {
 	copied, err = transition.ProcessSlots(ctx, copied, 1)
 	require.NoError(t, err)
 	require.NoError(t, service.cfg.BeaconDB.SaveState(ctx, copied, tRoot))
-	require.NoError(t, service.cfg.ForkChoiceStore.ProcessBlock(ctx, 0, tRoot, tRoot, tRoot, 1, 1))
+	require.NoError(t, service.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx, 0, tRoot, tRoot, 1, 1))
 	require.NoError(t, service.cfg.AttPool.SaveForkchoiceAttestations(atts))
 	service.processAttestations(ctx)
 	require.Equal(t, 0, len(service.cfg.AttPool.ForkchoiceAttestations()))

beacon-chain/blockchain/receive_block.go

@@ -64,7 +64,9 @@ func (s *Service) ReceiveBlock(ctx context.Context, block block.SignedBeaconBloc
 		return err
 	}
 	// Log state transition data.
-	logStateTransitionData(blockCopy.Block())
+	if err := logStateTransitionData(blockCopy.Block()); err != nil {
+		return err
+	}
 
 	return nil
 }
@@ -86,10 +88,12 @@ func (s *Service) ReceiveBlockBatch(ctx context.Context, blocks []block.SignedBe
 
 	for i, b := range blocks {
 		blockCopy := b.Copy()
+		// TODO(10261) check optimistic status
 		if err = s.handleBlockAfterBatchVerify(ctx, blockCopy, blkRoots[i], fCheckpoints[i], jCheckpoints[i]); err != nil {
 			tracing.AnnotateError(span, err)
 			return err
 		}
+
 		// Send notification of the processed block to the state feed.
 		s.cfg.StateNotifier.StateFeed().Send(&feed.Event{
 			Type: statefeed.BlockProcessed,

beacon-chain/blockchain/receive_block_test.go

@@ -192,7 +192,7 @@ func TestService_ReceiveBlockUpdateHead(t *testing.T) {
 		t.Errorf("Received %d state notifications, expected at least 1", recvd)
 	}
 	// Verify fork choice has processed the block. (Genesis block and the new block)
-	assert.Equal(t, 2, len(s.cfg.ForkChoiceStore.Nodes()))
+	assert.Equal(t, 2, s.cfg.ForkChoiceStore.NodeCount())
 }
 
 func TestService_ReceiveBlockBatch(t *testing.T) {

beacon-chain/blockchain/service.go

@@ -21,6 +21,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/transition"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
 	f "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice"
+	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/attestations"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/slashings"
@@ -31,6 +32,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state/stategen"
 	"github.com/prysmaticlabs/prysm/cmd/beacon-chain/flags"
+	"github.com/prysmaticlabs/prysm/config/features"
 	"github.com/prysmaticlabs/prysm/config/params"
 	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
 	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
@@ -83,6 +85,7 @@ type config struct {
 	StateGen                *stategen.State
 	SlasherAttestationsFeed *event.Feed
 	WeakSubjectivityCheckpt *ethpb.Checkpoint
+	BlockFetcher            powchain.POWBlockFetcher
 	FinalizedStateAtStartUp state.BeaconState
 	ExecutionEngineCaller   enginev1.Caller
 }
@@ -124,7 +127,7 @@ func (s *Service) Start() {
 	saved := s.cfg.FinalizedStateAtStartUp
 
 	if saved != nil && !saved.IsNil() {
-		if err := s.startFromSavedState(saved); err != nil {
+		if err := s.StartFromSavedState(saved); err != nil {
 			log.Fatal(err)
 		}
 	} else {
@@ -132,6 +135,7 @@ func (s *Service) Start() {
 			log.Fatal(err)
 		}
 	}
+	s.spawnProcessAttestationsRoutine(s.cfg.StateNotifier.StateFeed())
 }
 
 // Stop the blockchain service's main event loop and associated goroutines.
@@ -160,9 +164,9 @@ func (s *Service) Status() error {
 	return nil
 }
 
-func (s *Service) startFromSavedState(saved state.BeaconState) error {
+func (s *Service) StartFromSavedState(saved state.BeaconState) error {
 	log.Info("Blockchain data already exists in DB, initializing...")
-	s.genesisTime = time.Unix(int64(saved.GenesisTime()), 0)
+	s.genesisTime = time.Unix(int64(saved.GenesisTime()), 0) // lint:ignore uintcast -- Genesis time will not exceed int64 in your lifetime.
 	s.cfg.AttService.SetGenesisTime(saved.GenesisTime())
 
 	originRoot, err := s.originRootFromSavedState(s.ctx)
@@ -186,12 +190,13 @@ func (s *Service) startFromSavedState(saved state.BeaconState) error {
 	}
 	s.store = store.New(justified, finalized)
 
-	store := protoarray.New(justified.Epoch, finalized.Epoch, bytesutil.ToBytes32(finalized.Root))
-	s.cfg.ForkChoiceStore = store
-
-	if err := s.loadSyncedTips(originRoot, saved.Slot()); err != nil {
-		return err
+	var store f.ForkChoicer
+	if features.Get().EnableForkChoiceDoublyLinkedTree {
+		store = doublylinkedtree.New(justified.Epoch, finalized.Epoch)
+	} else {
+		store = protoarray.New(justified.Epoch, finalized.Epoch, bytesutil.ToBytes32(finalized.Root))
 	}
+	s.cfg.ForkChoiceStore = store
 
 	ss, err := slots.EpochStart(finalized.Epoch)
 	if err != nil {
@@ -223,8 +228,6 @@ func (s *Service) startFromSavedState(saved state.BeaconState) error {
 		},
 	})
 
-	s.spawnProcessAttestationsRoutine(s.cfg.StateNotifier.StateFeed())
-
 	return nil
 }
 
@@ -333,7 +336,6 @@ func (s *Service) startFromPOWChain() error {
 		stateChannel := make(chan *feed.Event, 1)
 		stateSub := s.cfg.StateNotifier.StateFeed().Subscribe(stateChannel)
 		defer stateSub.Unsubscribe()
-		s.spawnProcessAttestationsRoutine(s.cfg.StateNotifier.StateFeed())
 		for {
 			select {
 			case event := <-stateChannel:
@@ -447,15 +449,17 @@ func (s *Service) saveGenesisData(ctx context.Context, genesisState state.Beacon
 	genesisCheckpoint := genesisState.FinalizedCheckpoint()
 	s.store = store.New(genesisCheckpoint, genesisCheckpoint)
 
-	if err := s.cfg.ForkChoiceStore.ProcessBlock(ctx,
+	if err := s.cfg.ForkChoiceStore.InsertOptimisticBlock(ctx,
 		genesisBlk.Block().Slot(),
 		genesisBlkRoot,
 		params.BeaconConfig().ZeroHash,
-		[32]byte{},
 		genesisCheckpoint.Epoch,
 		genesisCheckpoint.Epoch); err != nil {
 		log.Fatalf("Could not process genesis block for fork choice: %v", err)
 	}
+	if err := s.cfg.ForkChoiceStore.SetOptimisticToValid(ctx, genesisBlkRoot); err != nil {
+		log.Fatalf("Could not set optimistic status of genesis block to false: %v", err)
+	}
 
 	s.setHead(genesisBlkRoot, genesisBlk, genesisState)
 	return nil

beacon-chain/blockchain/service_test.go

@@ -8,7 +8,6 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
-	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/async/event"
 	"github.com/prysmaticlabs/prysm/beacon-chain/blockchain/store"
 	mock "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/testing"
@@ -20,6 +19,7 @@ import (
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/transition"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
+	doublylinkedtree "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree"
 	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
 	"github.com/prysmaticlabs/prysm/beacon-chain/operations/attestations"
 	"github.com/prysmaticlabs/prysm/beacon-chain/p2p"
@@ -164,74 +164,6 @@ func TestChainStartStop_Initialized(t *testing.T) {
 	require.LogsContain(t, hook, "data already exists")
 }
 
-func TestChainStart_SyncedTipsInDB(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	chainService := setupBeaconChain(t, beaconDB)
-
-	genesisBlk := util.NewBeaconBlock()
-	blkRoot, err := genesisBlk.Block.HashTreeRoot()
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(genesisBlk)))
-	s, err := util.NewBeaconState()
-	require.NoError(t, err)
-	require.NoError(t, s.SetSlot(1))
-	require.NoError(t, beaconDB.SaveState(ctx, s, blkRoot))
-	require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, blkRoot))
-	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, blkRoot))
-	require.NoError(t, beaconDB.SaveJustifiedCheckpoint(ctx, &ethpb.Checkpoint{Root: blkRoot[:]}))
-	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Root: blkRoot[:]}))
-	chainService.cfg.FinalizedStateAtStartUp = s
-
-	tips := make(map[[32]byte]types.Slot)
-	tips[bytesutil.ToBytes32([]byte{'a'})] = 1
-	tips[bytesutil.ToBytes32([]byte{'b'})] = 2
-	require.NoError(t, beaconDB.UpdateValidatedTips(ctx, tips))
-
-	// Test the start function.
-	chainService.Start()
-
-	// Test synced Tips in DB
-	tips2 := chainService.cfg.ForkChoiceStore.SyncedTips()
-	require.Equal(t, len(tips2), len(tips))
-	for k, v := range tips {
-		v2, ok := tips2[k]
-		require.Equal(t, true, ok)
-		require.Equal(t, v, v2)
-	}
-}
-
-func TestChainStart_SyncedTipsNotInDB(t *testing.T) {
-	ctx := context.Background()
-	beaconDB := testDB.SetupDB(t)
-
-	chainService := setupBeaconChain(t, beaconDB)
-
-	genesisBlk := util.NewBeaconBlock()
-	blkRoot, err := genesisBlk.Block.HashTreeRoot()
-	require.NoError(t, err)
-	require.NoError(t, beaconDB.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(genesisBlk)))
-	s, err := util.NewBeaconState()
-	require.NoError(t, err)
-	require.NoError(t, s.SetSlot(1))
-	require.NoError(t, beaconDB.SaveState(ctx, s, blkRoot))
-	require.NoError(t, beaconDB.SaveHeadBlockRoot(ctx, blkRoot))
-	require.NoError(t, beaconDB.SaveGenesisBlockRoot(ctx, blkRoot))
-	require.NoError(t, beaconDB.SaveJustifiedCheckpoint(ctx, &ethpb.Checkpoint{Root: blkRoot[:]}))
-	require.NoError(t, beaconDB.SaveFinalizedCheckpoint(ctx, &ethpb.Checkpoint{Root: blkRoot[:]}))
-	chainService.cfg.FinalizedStateAtStartUp = s
-	// Test the start function.
-	chainService.Start()
-
-	// Test synced Tips in DB
-	tips := chainService.cfg.ForkChoiceStore.SyncedTips()
-	require.Equal(t, 1, len(tips))
-	slot, ok := tips[blkRoot]
-	require.Equal(t, true, ok)
-	require.Equal(t, types.Slot(1), slot)
-}
-
 func TestChainStartStop_GenesisZeroHashes(t *testing.T) {
 	hook := logTest.NewGlobal()
 	ctx := context.Background()
@@ -358,7 +290,7 @@ func TestChainService_InitializeChainInfo(t *testing.T) {
 	require.NoError(t, err)
 	c, err := NewService(ctx, WithDatabase(beaconDB), WithStateGen(stategen.New(beaconDB)), WithAttestationService(attSrv), WithStateNotifier(&mock.MockStateNotifier{}), WithFinalizedStateAtStartUp(headState))
 	require.NoError(t, err)
-	require.NoError(t, c.startFromSavedState(headState))
+	require.NoError(t, c.StartFromSavedState(headState))
 	headBlk, err := c.HeadBlock(ctx)
 	require.NoError(t, err)
 	assert.DeepEqual(t, headBlock, headBlk.Proto(), "Head block incorrect")
@@ -401,7 +333,7 @@ func TestChainService_InitializeChainInfo_SetHeadAtGenesis(t *testing.T) {
 	require.NoError(t, err)
 	c, err := NewService(ctx, WithDatabase(beaconDB), WithStateGen(stategen.New(beaconDB)), WithAttestationService(attSrv), WithStateNotifier(&mock.MockStateNotifier{}))
 	require.NoError(t, err)
-	require.NoError(t, c.startFromSavedState(headState))
+	require.NoError(t, c.StartFromSavedState(headState))
 	s, err := c.HeadState(ctx)
 	require.NoError(t, err)
 	assert.DeepSSZEqual(t, headState.InnerStateUnsafe(), s.InnerStateUnsafe(), "Head state incorrect")
@@ -461,7 +393,7 @@ func TestChainService_InitializeChainInfo_HeadSync(t *testing.T) {
 	require.NoError(t, err)
 	c, err := NewService(ctx, WithDatabase(beaconDB), WithStateGen(stategen.New(beaconDB)), WithAttestationService(attSrv), WithStateNotifier(&mock.MockStateNotifier{}), WithFinalizedStateAtStartUp(headState))
 	require.NoError(t, err)
-	require.NoError(t, c.startFromSavedState(headState))
+	require.NoError(t, c.StartFromSavedState(headState))
 	s, err := c.HeadState(ctx)
 	require.NoError(t, err)
 	assert.DeepSSZEqual(t, headState.InnerStateUnsafe(), s.InnerStateUnsafe(), "Head state incorrect")
@@ -515,7 +447,7 @@ func TestChainService_SaveHeadNoDB(t *testing.T) {
 	}
 }
 
-func TestHasBlock_ForkChoiceAndDB(t *testing.T) {
+func TestHasBlock_ForkChoiceAndDB_ProtoArray(t *testing.T) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(t)
 	s := &Service{
@@ -534,6 +466,25 @@ func TestHasBlock_ForkChoiceAndDB(t *testing.T) {
 	assert.Equal(t, true, s.hasBlock(ctx, r), "Should have block")
 }
 
+func TestHasBlock_ForkChoiceAndDB_DoublyLinkedTree(t *testing.T) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(t)
+	s := &Service{
+		cfg:   &config{ForkChoiceStore: doublylinkedtree.New(0, 0), BeaconDB: beaconDB},
+		store: &store.Store{},
+	}
+	s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Epoch: 0, Root: params.BeaconConfig().ZeroHash[:]})
+	block := util.NewBeaconBlock()
+	r, err := block.Block.HashTreeRoot()
+	require.NoError(t, err)
+	beaconState, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, s.insertBlockAndAttestationsToForkChoiceStore(ctx, wrapper.WrappedPhase0SignedBeaconBlock(block).Block(), r, beaconState))
+
+	assert.Equal(t, false, s.hasBlock(ctx, [32]byte{}), "Should not have block")
+	assert.Equal(t, true, s.hasBlock(ctx, r), "Should have block")
+}
+
 func TestServiceStop_SaveCachedBlocks(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	beaconDB := testDB.SetupDB(t)
@@ -582,7 +533,7 @@ func BenchmarkHasBlockDB(b *testing.B) {
 	}
 }
 
-func BenchmarkHasBlockForkChoiceStore(b *testing.B) {
+func BenchmarkHasBlockForkChoiceStore_ProtoArray(b *testing.B) {
 	ctx := context.Background()
 	beaconDB := testDB.SetupDB(b)
 	s := &Service{
@@ -603,3 +554,24 @@ func BenchmarkHasBlockForkChoiceStore(b *testing.B) {
 		require.Equal(b, true, s.cfg.ForkChoiceStore.HasNode(r), "Block is not in fork choice store")
 	}
 }
+func BenchmarkHasBlockForkChoiceStore_DoublyLinkedTree(b *testing.B) {
+	ctx := context.Background()
+	beaconDB := testDB.SetupDB(b)
+	s := &Service{
+		cfg:   &config{ForkChoiceStore: doublylinkedtree.New(0, 0), BeaconDB: beaconDB},
+		store: &store.Store{},
+	}
+	s.store.SetFinalizedCheckpt(&ethpb.Checkpoint{Epoch: 0, Root: params.BeaconConfig().ZeroHash[:]})
+	block := &ethpb.SignedBeaconBlock{Block: &ethpb.BeaconBlock{Body: &ethpb.BeaconBlockBody{}}}
+	r, err := block.Block.HashTreeRoot()
+	require.NoError(b, err)
+	bs := &ethpb.BeaconState{FinalizedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}, CurrentJustifiedCheckpoint: &ethpb.Checkpoint{Root: make([]byte, 32)}}
+	beaconState, err := v1.InitializeFromProto(bs)
+	require.NoError(b, err)
+	require.NoError(b, s.insertBlockAndAttestationsToForkChoiceStore(ctx, wrapper.WrappedPhase0SignedBeaconBlock(block).Block(), r, beaconState))
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		require.Equal(b, true, s.cfg.ForkChoiceStore.HasNode(r), "Block is not in fork choice store")
+	}
+}

beacon-chain/blockchain/testing/BUILD.bazel

@@ -18,7 +18,7 @@ go_library(
         "//beacon-chain/core/feed/state:go_default_library",
         "//beacon-chain/core/helpers:go_default_library",
         "//beacon-chain/db:go_default_library",
-        "//beacon-chain/forkchoice/protoarray:go_default_library",
+        "//beacon-chain/forkchoice:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",

beacon-chain/blockchain/testing/mock.go

@@ -18,7 +18,7 @@ import (
 	statefeed "github.com/prysmaticlabs/prysm/beacon-chain/core/feed/state"
 	"github.com/prysmaticlabs/prysm/beacon-chain/core/helpers"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
-	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
+	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice"
 	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/config/params"
@@ -41,7 +41,6 @@ type ChainService struct {
 	PreviousJustifiedCheckPoint *ethpb.Checkpoint
 	Slot                        *types.Slot // Pointer because 0 is a useful value, so checking against it can be incorrect.
 	Balance                     *precompute.Balance
-	ForkChoiceStore             *protoarray.Store
 	CanonicalRoots              map[[32]byte]bool
 	Fork                        *ethpb.Fork
 	ETH1Data                    *ethpb.Eth1Data
@@ -61,6 +60,12 @@ type ChainService struct {
 	SyncContributionProofDomain []byte
 	SyncCommitteePubkeys        [][]byte
 	Genesis                     time.Time
+	ForkChoiceStore             forkchoice.ForkChoicer
+}
+
+// ForkChoicer mocks the same method in the chain service
+func (s *ChainService) ForkChoicer() forkchoice.ForkChoicer {
+	return s.ForkChoiceStore
 }
 
 // StateNotifier mocks the same method in the chain service.
@@ -320,11 +325,6 @@ func (s *ChainService) HeadETH1Data() *ethpb.Eth1Data {
 	return s.ETH1Data
 }
 
-// ProtoArrayStore mocks the same method in the chain service.
-func (s *ChainService) ProtoArrayStore() *protoarray.Store {
-	return s.ForkChoiceStore
-}
-
 // GenesisTime mocks the same method in the chain service.
 func (s *ChainService) GenesisTime() time.Time {
 	return s.Genesis
@@ -447,6 +447,6 @@ func (s *ChainService) IsOptimistic(_ context.Context) (bool, error) {
 }
 
 // IsOptimisticForRoot mocks the same method in the chain service.
-func (s *ChainService) IsOptimisticForRoot(_ context.Context, _ [32]byte, _ types.Slot) (bool, error) {
-	return false, nil
+func (s *ChainService) IsOptimisticForRoot(_ context.Context, _ [32]byte) (bool, error) {
+	return s.Optimistic, nil
 }

beacon-chain/cache/active_balance.go

@@ -1,3 +1,4 @@
+//go:build !fuzz
 // +build !fuzz
 
 package cache
@@ -17,10 +18,12 @@ import (
 	"github.com/prysmaticlabs/prysm/config/params"
 )
 
-var (
+const (
 	// maxBalanceCacheSize defines the max number of active balances can cache.
-	maxBalanceCacheSize = uint64(4)
+	maxBalanceCacheSize = int(4)
+)
 
+var (
 	// BalanceCacheMiss tracks the number of balance requests that aren't present in the cache.
 	balanceCacheMiss = promauto.NewCounter(prometheus.CounterOpts{
 		Name: "total_effective_balance_cache_miss",
@@ -42,7 +45,7 @@ type BalanceCache struct {
 // NewEffectiveBalanceCache creates a new effective balance cache for storing/accessing total balance by epoch.
 func NewEffectiveBalanceCache() *BalanceCache {
 	return &BalanceCache{
-		cache: lruwrpr.New(int(maxBalanceCacheSize)),
+		cache: lruwrpr.New(maxBalanceCacheSize),
 	}
 }
 

beacon-chain/cache/active_balance_disabled.go

@@ -1,3 +1,4 @@
+//go:build fuzz
 // +build fuzz
 
 package cache

beacon-chain/cache/committee.go

@@ -1,3 +1,4 @@
+//go:build !fuzz
 // +build !fuzz
 
 package cache
@@ -19,11 +20,13 @@ import (
 	mathutil "github.com/prysmaticlabs/prysm/math"
 )
 
-var (
+const (
 	// maxCommitteesCacheSize defines the max number of shuffled committees on per randao basis can cache.
 	// Due to reorgs and long finality, it's good to keep the old cache around for quickly switch over.
-	maxCommitteesCacheSize = uint64(32)
+	maxCommitteesCacheSize = int(32)
+)
 
+var (
 	// CommitteeCacheMiss tracks the number of committee requests that aren't present in the cache.
 	CommitteeCacheMiss = promauto.NewCounter(prometheus.CounterOpts{
 		Name: "committee_cache_miss",
@@ -55,7 +58,7 @@ func committeeKeyFn(obj interface{}) (string, error) {
 // NewCommitteesCache creates a new committee cache for storing/accessing shuffled indices of a committee.
 func NewCommitteesCache() *CommitteeCache {
 	return &CommitteeCache{
-		CommitteeCache: lruwrpr.New(int(maxCommitteesCacheSize)),
+		CommitteeCache: lruwrpr.New(maxCommitteesCacheSize),
 		inProgress:     make(map[string]bool),
 	}
 }

beacon-chain/cache/committee_disabled.go

@@ -1,3 +1,4 @@
+//go:build fuzz
 // +build fuzz
 
 // This file is used in fuzzer builds to bypass global committee caches.

beacon-chain/cache/committee_fuzz_test.go

@@ -33,7 +33,7 @@ func TestCommitteeCache_FuzzCommitteesByEpoch(t *testing.T) {
 		require.NoError(t, err)
 	}
 
-	assert.Equal(t, maxCommitteesCacheSize, uint64(len(cache.CommitteeCache.Keys())), "Incorrect key size")
+	assert.Equal(t, maxCommitteesCacheSize, len(cache.CommitteeCache.Keys()), "Incorrect key size")
 }
 
 func TestCommitteeCache_FuzzActiveIndices(t *testing.T) {
@@ -50,5 +50,5 @@ func TestCommitteeCache_FuzzActiveIndices(t *testing.T) {
 		assert.DeepEqual(t, c.SortedIndices, indices)
 	}
 
-	assert.Equal(t, maxCommitteesCacheSize, uint64(len(cache.CommitteeCache.Keys())), "Incorrect key size")
+	assert.Equal(t, maxCommitteesCacheSize, len(cache.CommitteeCache.Keys()), "Incorrect key size")
 }

beacon-chain/cache/committee_test.go

@@ -102,7 +102,7 @@ func TestCommitteeCache_CanRotate(t *testing.T) {
 	}
 
 	k := cache.CommitteeCache.Keys()
-	assert.Equal(t, maxCommitteesCacheSize, uint64(len(k)))
+	assert.Equal(t, maxCommitteesCacheSize, len(k))
 
 	sort.Slice(k, func(i, j int) bool {
 		return k[i].(string) < k[j].(string)

beacon-chain/cache/proposer_indices.go

@@ -1,3 +1,4 @@
+//go:build !fuzz
 // +build !fuzz
 
 package cache

beacon-chain/cache/proposer_indices_disabled.go

@@ -1,3 +1,4 @@
+//go:build fuzz
 // +build fuzz
 
 // This file is used in fuzzer builds to bypass proposer indices caches.

beacon-chain/cache/subnet_ids.go

@@ -27,7 +27,7 @@ var SubnetIDs = newSubnetIDs()
 func newSubnetIDs() *subnetIDs {
 	// Given a node can calculate committee assignments of current epoch and next epoch.
 	// Max size is set to 2 epoch length.
-	cacheSize := int(params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().MaxCommitteesPerSlot * 2))
+	cacheSize := int(params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().MaxCommitteesPerSlot * 2)) // lint:ignore uintcast -- constant values that would panic on startup if negative.
 	attesterCache := lruwrpr.New(cacheSize)
 	aggregatorCache := lruwrpr.New(cacheSize)
 	epochDuration := time.Duration(params.BeaconConfig().SlotsPerEpoch.Mul(params.BeaconConfig().SecondsPerSlot))

beacon-chain/cache/sync_committee.go

@@ -1,3 +1,4 @@
+//go:build !fuzz
 // +build !fuzz
 
 package cache

beacon-chain/cache/sync_committee_disabled.go

@@ -1,3 +1,4 @@
+//go:build fuzz
 // +build fuzz
 
 package cache

beacon-chain/core/blocks/deposit.go

@@ -225,7 +225,7 @@ func verifyDeposit(beaconState state.ReadOnlyBeaconState, deposit *ethpb.Deposit
 	if ok := trie.VerifyMerkleProofWithDepth(
 		receiptRoot,
 		leaf[:],
-		int(beaconState.Eth1DepositIndex()),
+		beaconState.Eth1DepositIndex(),
 		deposit.Proof,
 		params.BeaconConfig().DepositContractTreeDepth,
 	); !ok {

beacon-chain/core/blocks/payload.go

@@ -23,6 +23,8 @@ import (
 // Spec code:
 // def is_merge_transition_complete(state: BeaconState) -> bool:
 //    return state.latest_execution_payload_header != ExecutionPayloadHeader()
+//
+// Deprecated: Use `IsMergeTransitionBlockUsingPayloadHeader` instead.
 func MergeTransitionComplete(st state.BeaconState) (bool, error) {
 	h, err := st.LatestExecutionPayloadHeader()
 	if err != nil {
@@ -51,6 +53,16 @@ func MergeTransitionBlock(st state.BeaconState, body block.BeaconBlockBody) (boo
 	return ExecutionBlock(body)
 }
 
+// IsMergeTransitionBlockUsingPayloadHeader returns true if the input block is the terminal merge block.
+// Terminal merge block must be associated with an empty payload header.
+// This is an optimized version of MergeTransitionComplete where beacon state is not required as an argument.
+func IsMergeTransitionBlockUsingPayloadHeader(h *ethpb.ExecutionPayloadHeader, body block.BeaconBlockBody) (bool, error) {
+	if !isEmptyHeader(h) {
+		return false, nil
+	}
+	return ExecutionBlock(body)
+}
+
 // ExecutionBlock returns whether the block has a non-empty ExecutionPayload.
 //
 // Spec code:

beacon-chain/core/blocks/payload_test.go

@@ -350,6 +350,185 @@ func Test_MergeBlock(t *testing.T) {
 	}
 }
 
+func Test_IsMergeTransitionBlockUsingPayloadHeader(t *testing.T) {
+	tests := []struct {
+		name    string
+		payload *enginev1.ExecutionPayload
+		header  *ethpb.ExecutionPayloadHeader
+		want    bool
+	}{
+		{
+			name:    "empty header, empty payload",
+			payload: emptyPayload(),
+			header:  emptyPayloadHeader(),
+			want:    false,
+		},
+		{
+			name:    "non-empty header, empty payload",
+			payload: emptyPayload(),
+			header: func() *ethpb.ExecutionPayloadHeader {
+				h := emptyPayloadHeader()
+				h.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
+				return h
+			}(),
+			want: false,
+		},
+		{
+			name: "empty header, payload has parent hash",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.ParentHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has fee recipient",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.FeeRecipient = bytesutil.PadTo([]byte{'a'}, fieldparams.FeeRecipientLength)
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has state root",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.StateRoot = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has receipt root",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.ReceiptsRoot = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has logs bloom",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.LogsBloom = bytesutil.PadTo([]byte{'a'}, fieldparams.LogsBloomLength)
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has random",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.PrevRandao = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has base fee",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.BaseFeePerGas = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has block hash",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.BlockHash = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has tx",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.Transactions = [][]byte{{'a'}}
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has extra data",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.ExtraData = bytesutil.PadTo([]byte{'a'}, fieldparams.RootLength)
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has block number",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.BlockNumber = 1
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has gas limit",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.GasLimit = 1
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has gas used",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.GasUsed = 1
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+		{
+			name: "empty header, payload has timestamp",
+			payload: func() *enginev1.ExecutionPayload {
+				p := emptyPayload()
+				p.Timestamp = 1
+				return p
+			}(),
+			header: emptyPayloadHeader(),
+			want:   true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			blk := util.NewBeaconBlockBellatrix()
+			blk.Block.Body.ExecutionPayload = tt.payload
+			body, err := wrapper.WrappedBellatrixBeaconBlockBody(blk.Block.Body)
+			require.NoError(t, err)
+			got, err := blocks.IsMergeTransitionBlockUsingPayloadHeader(tt.header, body)
+			require.NoError(t, err)
+			if got != tt.want {
+				t.Errorf("MergeTransitionBlock() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
 func Test_IsExecutionBlock(t *testing.T) {
 	tests := []struct {
 		name    string

beacon-chain/core/helpers/block.go

@@ -11,18 +11,22 @@ import (
 	"github.com/prysmaticlabs/prysm/time/slots"
 )
 
+var ErrNilSignedBeaconBlock = errors.New("signed beacon block can't be nil")
+var ErrNilBeaconBlock = errors.New("beacon block can't be nil")
+var ErrNilBeaconBlockBody = errors.New("beacon block body can't be nil")
+
 // BeaconBlockIsNil checks if any composite field of input signed beacon block is nil.
 // Access to these nil fields will result in run time panic,
 // it is recommended to run these checks as first line of defense.
 func BeaconBlockIsNil(b block.SignedBeaconBlock) error {
 	if b == nil || b.IsNil() {
-		return errors.New("signed beacon block can't be nil")
+		return ErrNilSignedBeaconBlock
 	}
 	if b.Block().IsNil() {
-		return errors.New("beacon block can't be nil")
+		return ErrNilBeaconBlock
 	}
 	if b.Block().Body().IsNil() {
-		return errors.New("beacon block body can't be nil")
+		return ErrNilBeaconBlockBody
 	}
 	return nil
 }

beacon-chain/core/time/BUILD.bazel

@@ -17,13 +17,15 @@ go_library(
 go_test(
     name = "go_default_test",
     srcs = ["slot_epoch_test.go"],
-    embed = [":go_default_library"],
     deps = [
+        ":go_default_library",
+        "//beacon-chain/state:go_default_library",
         "//beacon-chain/state/v1:go_default_library",
         "//config/params:go_default_library",
         "//proto/prysm/v1alpha1:go_default_library",
         "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
+        "//testing/util:go_default_library",
         "//time/slots:go_default_library",
         "@com_github_prysmaticlabs_eth2_types//:go_default_library",
     ],

beacon-chain/core/time/slot_epoch.go

@@ -46,9 +46,9 @@ func NextEpoch(state state.ReadOnlyBeaconState) types.Epoch {
 	return slots.ToEpoch(state.Slot()) + 1
 }
 
-// AltairCompatible returns if the input state `s` is altair compatible and input epoch `e` is higher equal than fork epoch.
-func AltairCompatible(s state.BeaconState, e types.Epoch) bool {
-	return s.Version() == version.Altair && e >= params.BeaconConfig().AltairForkEpoch
+// HigherEqualThanAltairVersionAndEpoch returns if the input state `s` has a higher version number than Altair state and input epoch `e` is higher equal than fork epoch.
+func HigherEqualThanAltairVersionAndEpoch(s state.BeaconState, e types.Epoch) bool {
+	return s.Version() >= version.Altair && e >= params.BeaconConfig().AltairForkEpoch
 }
 
 // CanUpgradeToAltair returns true if the input `slot` can upgrade to Altair.

beacon-chain/core/time/slot_epoch_test.go

@@ -1,14 +1,17 @@
-package time
+package time_test
 
 import (
 	"testing"
 
 	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/time"
+	"github.com/prysmaticlabs/prysm/beacon-chain/state"
 	v1 "github.com/prysmaticlabs/prysm/beacon-chain/state/v1"
 	"github.com/prysmaticlabs/prysm/config/params"
 	eth "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"github.com/prysmaticlabs/prysm/testing/assert"
 	"github.com/prysmaticlabs/prysm/testing/require"
+	"github.com/prysmaticlabs/prysm/testing/util"
 	"github.com/prysmaticlabs/prysm/time/slots"
 )
 
@@ -42,7 +45,7 @@ func TestCurrentEpoch_OK(t *testing.T) {
 	for _, tt := range tests {
 		state, err := v1.InitializeFromProto(&eth.BeaconState{Slot: tt.slot})
 		require.NoError(t, err)
-		assert.Equal(t, tt.epoch, CurrentEpoch(state), "ActiveCurrentEpoch(%d)", state.Slot())
+		assert.Equal(t, tt.epoch, time.CurrentEpoch(state), "ActiveCurrentEpoch(%d)", state.Slot())
 	}
 }
 
@@ -58,7 +61,7 @@ func TestPrevEpoch_OK(t *testing.T) {
 	for _, tt := range tests {
 		state, err := v1.InitializeFromProto(&eth.BeaconState{Slot: tt.slot})
 		require.NoError(t, err)
-		assert.Equal(t, tt.epoch, PrevEpoch(state), "ActivePrevEpoch(%d)", state.Slot())
+		assert.Equal(t, tt.epoch, time.PrevEpoch(state), "ActivePrevEpoch(%d)", state.Slot())
 	}
 }
 
@@ -76,7 +79,7 @@ func TestNextEpoch_OK(t *testing.T) {
 	for _, tt := range tests {
 		state, err := v1.InitializeFromProto(&eth.BeaconState{Slot: tt.slot})
 		require.NoError(t, err)
-		assert.Equal(t, tt.epoch, NextEpoch(state), "NextEpoch(%d)", state.Slot())
+		assert.Equal(t, tt.epoch, time.NextEpoch(state), "NextEpoch(%d)", state.Slot())
 	}
 }
 
@@ -108,7 +111,7 @@ func TestCanUpgradeToAltair(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := CanUpgradeToAltair(tt.slot); got != tt.want {
+			if got := time.CanUpgradeToAltair(tt.slot); got != tt.want {
 				t.Errorf("canUpgradeToAltair() = %v, want %v", got, tt.want)
 			}
 		})
@@ -143,7 +146,7 @@ func TestCanUpgradeBellatrix(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if got := CanUpgradeToBellatrix(tt.slot); got != tt.want {
+			if got := time.CanUpgradeToBellatrix(tt.slot); got != tt.want {
 				t.Errorf("CanUpgradeToBellatrix() = %v, want %v", got, tt.want)
 			}
 		})
@@ -178,6 +181,85 @@ func TestCanProcessEpoch_TrueOnEpochsLastSlot(t *testing.T) {
 		b := &eth.BeaconState{Slot: tt.slot}
 		s, err := v1.InitializeFromProto(b)
 		require.NoError(t, err)
-		assert.Equal(t, tt.canProcessEpoch, CanProcessEpoch(s), "CanProcessEpoch(%d)", tt.slot)
+		assert.Equal(t, tt.canProcessEpoch, time.CanProcessEpoch(s), "CanProcessEpoch(%d)", tt.slot)
+	}
+}
+
+func TestAltairCompatible(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig()
+	cfg.AltairForkEpoch = 1
+	cfg.BellatrixForkEpoch = 2
+	params.OverrideBeaconConfig(cfg)
+
+	type args struct {
+		s state.BeaconState
+		e types.Epoch
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{
+			name: "phase0 state",
+			args: args{
+				s: func() state.BeaconState {
+					st, _ := util.DeterministicGenesisState(t, 1)
+					return st
+				}(),
+			},
+			want: false,
+		},
+		{
+			name: "altair state, altair epoch",
+			args: args{
+				s: func() state.BeaconState {
+					st, _ := util.DeterministicGenesisStateAltair(t, 1)
+					return st
+				}(),
+				e: params.BeaconConfig().AltairForkEpoch,
+			},
+			want: true,
+		},
+		{
+			name: "bellatrix state, bellatrix epoch",
+			args: args{
+				s: func() state.BeaconState {
+					st, _ := util.DeterministicGenesisStateBellatrix(t, 1)
+					return st
+				}(),
+				e: params.BeaconConfig().BellatrixForkEpoch,
+			},
+			want: true,
+		},
+		{
+			name: "bellatrix state, altair epoch",
+			args: args{
+				s: func() state.BeaconState {
+					st, _ := util.DeterministicGenesisStateBellatrix(t, 1)
+					return st
+				}(),
+				e: params.BeaconConfig().AltairForkEpoch,
+			},
+			want: true,
+		},
+		{
+			name: "bellatrix state, phase0 epoch",
+			args: args{
+				s: func() state.BeaconState {
+					st, _ := util.DeterministicGenesisStateBellatrix(t, 1)
+					return st
+				}(),
+			},
+			want: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := time.HigherEqualThanAltairVersionAndEpoch(tt.args.s, tt.args.e); got != tt.want {
+				t.Errorf("HigherEqualThanAltairVersionAndEpoch() = %v, want %v", got, tt.want)
+			}
+		})
 	}
 }

beacon-chain/core/transition/bellatrix_transition_no_verify_sig_test.go

@@ -245,7 +245,7 @@ func createFullBellatrixBlockWithOperations(t *testing.T) (state.BeaconState,
 					ReceiptsRoot:  make([]byte, fieldparams.RootLength),
 					LogsBloom:     make([]byte, fieldparams.LogsBloomLength),
 					PrevRandao:    make([]byte, fieldparams.RootLength),
-					BaseFeePerGas: make([]byte, fieldparams.RootLength),
+					BaseFeePerGas: bytesutil.PadTo([]byte{1, 2, 3, 4}, fieldparams.RootLength),
 					BlockHash:     make([]byte, fieldparams.RootLength),
 					Transactions:  make([][]byte, 0),
 					ExtraData:     make([]byte, 0),

beacon-chain/core/transition/transition.go

@@ -92,7 +92,7 @@ func ExecuteStateTransition(
 func ProcessSlot(ctx context.Context, state state.BeaconState) (state.BeaconState, error) {
 	ctx, span := trace.StartSpan(ctx, "core.state.ProcessSlot")
 	defer span.End()
-	span.AddAttributes(trace.Int64Attribute("slot", int64(state.Slot())))
+	span.AddAttributes(trace.Int64Attribute("slot", int64(state.Slot()))) // lint:ignore uintcast -- This is OK for tracing.
 
 	prevStateRoot, err := state.HashTreeRoot(ctx)
 	if err != nil {
@@ -190,7 +190,7 @@ func ProcessSlots(ctx context.Context, state state.BeaconState, slot types.Slot)
 	if state == nil || state.IsNil() {
 		return nil, errors.New("nil state")
 	}
-	span.AddAttributes(trace.Int64Attribute("slots", int64(slot)-int64(state.Slot())))
+	span.AddAttributes(trace.Int64Attribute("slots", int64(slot)-int64(state.Slot()))) // lint:ignore uintcast -- This is OK for tracing.
 
 	// The block must have a higher slot than parent state.
 	if state.Slot() >= slot {
@@ -354,7 +354,7 @@ func VerifyOperationLengths(_ context.Context, state state.BeaconState, b block.
 func ProcessEpochPrecompute(ctx context.Context, state state.BeaconState) (state.BeaconState, error) {
 	ctx, span := trace.StartSpan(ctx, "core.state.ProcessEpochPrecompute")
 	defer span.End()
-	span.AddAttributes(trace.Int64Attribute("epoch", int64(time.CurrentEpoch(state))))
+	span.AddAttributes(trace.Int64Attribute("epoch", int64(time.CurrentEpoch(state)))) // lint:ignore uintcast -- This is OK for tracing.
 
 	if state == nil || state.IsNil() {
 		return nil, errors.New("nil state")

beacon-chain/core/transition/transition_no_verify_sig.go

@@ -137,16 +137,6 @@ func CalculateStateRoot(
 	if err != nil {
 		return [32]byte{}, errors.Wrap(err, "could not process block")
 	}
-	if signed.Version() == version.Altair || signed.Version() == version.Bellatrix {
-		sa, err := signed.Block().Body().SyncAggregate()
-		if err != nil {
-			return [32]byte{}, err
-		}
-		state, err = altair.ProcessSyncAggregate(ctx, state, sa)
-		if err != nil {
-			return [32]byte{}, err
-		}
-	}
 
 	return state.HashTreeRoot(ctx)
 }
@@ -183,16 +173,6 @@ func ProcessBlockNoVerifyAnySig(
 	if err != nil {
 		return nil, nil, err
 	}
-	if signed.Version() == version.Altair || signed.Version() == version.Bellatrix {
-		sa, err := signed.Block().Body().SyncAggregate()
-		if err != nil {
-			return nil, nil, err
-		}
-		state, err = altair.ProcessSyncAggregate(ctx, state, sa)
-		if err != nil {
-			return nil, nil, err
-		}
-	}
 
 	bSet, err := b.BlockSignatureBatch(state, blk.ProposerIndex(), signed.Signature(), blk.HashTreeRoot)
 	if err != nil {
@@ -340,6 +320,19 @@ func ProcessBlockForStateRoot(
 		return nil, errors.Wrap(err, "could not process block operation")
 	}
 
+	if signed.Block().Version() == version.Phase0 {
+		return state, nil
+	}
+
+	sa, err := signed.Block().Body().SyncAggregate()
+	if err != nil {
+		return nil, errors.Wrap(err, "could not get sync aggregate from block")
+	}
+	state, err = altair.ProcessSyncAggregate(ctx, state, sa)
+	if err != nil {
+		return nil, errors.Wrap(err, "process_sync_aggregate failed")
+	}
+
 	return state, nil
 }
 

beacon-chain/db/errors.go

@@ -7,3 +7,9 @@ import "github.com/prysmaticlabs/prysm/beacon-chain/db/kv"
 // i/o error. This variable copies the value in the kv package to the same scope as the Database interfaces,
 // so that it is available to code paths that do not interact directly with the kv package.
 var ErrNotFound = kv.ErrNotFound
+
+// ErrNotFoundState wraps ErrNotFound for an error specific to a state not being found in the database.
+var ErrNotFoundState = kv.ErrNotFoundState
+
+// ErrNotFoundOriginBlockRoot wraps ErrNotFound for an error specific to the origin block root.
+var ErrNotFoundOriginBlockRoot = kv.ErrNotFoundOriginBlockRoot

beacon-chain/db/iface/interface.go

@@ -30,9 +30,9 @@ type ReadOnlyDatabase interface {
 	IsFinalizedBlock(ctx context.Context, blockRoot [32]byte) bool
 	FinalizedChildBlock(ctx context.Context, blockRoot [32]byte) (block.SignedBeaconBlock, error)
 	HighestSlotBlocksBelow(ctx context.Context, slot types.Slot) ([]block.SignedBeaconBlock, error)
-	ValidatedTips(ctx context.Context) (map[[32]byte]types.Slot, error)
 	// State related methods.
 	State(ctx context.Context, blockRoot [32]byte) (state.BeaconState, error)
+	StateOrError(ctx context.Context, blockRoot [32]byte) (state.BeaconState, error)
 	GenesisState(ctx context.Context) (state.BeaconState, error)
 	HasState(ctx context.Context, blockRoot [32]byte) bool
 	StateSummary(ctx context.Context, blockRoot [32]byte) (*ethpb.StateSummary, error)
@@ -45,11 +45,13 @@ type ReadOnlyDatabase interface {
 	HasArchivedPoint(ctx context.Context, slot types.Slot) bool
 	LastArchivedRoot(ctx context.Context) [32]byte
 	LastArchivedSlot(ctx context.Context) (types.Slot, error)
+	LastValidatedCheckpoint(ctx context.Context) (*ethpb.Checkpoint, error)
 	// Deposit contract related handlers.
 	DepositContractAddress(ctx context.Context) ([]byte, error)
 	// Powchain operations.
 	PowchainData(ctx context.Context) (*ethpb.ETH1ChainData, error)
-
+	// Fee reicipients operations.
+	FeeRecipientByValidatorID(ctx context.Context, id types.ValidatorIndex) (common.Address, error)
 	// origin checkpoint sync support
 	OriginBlockRoot(ctx context.Context) ([32]byte, error)
 }
@@ -63,7 +65,6 @@ type NoHeadAccessDatabase interface {
 	SaveBlock(ctx context.Context, block block.SignedBeaconBlock) error
 	SaveBlocks(ctx context.Context, blocks []block.SignedBeaconBlock) error
 	SaveGenesisBlockRoot(ctx context.Context, blockRoot [32]byte) error
-	UpdateValidatedTips(ctx context.Context, newVals map[[32]byte]types.Slot) error
 	// State related methods.
 	SaveState(ctx context.Context, state state.ReadOnlyBeaconState, blockRoot [32]byte) error
 	SaveStates(ctx context.Context, states []state.ReadOnlyBeaconState, blockRoots [][32]byte) error
@@ -74,12 +75,15 @@ type NoHeadAccessDatabase interface {
 	// Checkpoint operations.
 	SaveJustifiedCheckpoint(ctx context.Context, checkpoint *ethpb.Checkpoint) error
 	SaveFinalizedCheckpoint(ctx context.Context, checkpoint *ethpb.Checkpoint) error
+	SaveLastValidatedCheckpoint(ctx context.Context, checkpoint *ethpb.Checkpoint) error
 	// Deposit contract related handlers.
 	SaveDepositContractAddress(ctx context.Context, addr common.Address) error
 	// Powchain operations.
 	SavePowchainData(ctx context.Context, data *ethpb.ETH1ChainData) error
 	// Run any required database migrations.
 	RunMigrations(ctx context.Context) error
+	// Fee reicipients operations.
+	SaveFeeRecipientsByValidatorIDs(ctx context.Context, ids []types.ValidatorIndex, addrs []common.Address) error
 
 	CleanUpDirtyStates(ctx context.Context, slotsPerArchivedPoint types.Slot) error
 }

beacon-chain/db/kv/BUILD.bazel

@@ -25,7 +25,7 @@ go_library(
         "state_summary.go",
         "state_summary_cache.go",
         "utils.go",
-        "validated_tips.go",
+        "validated_checkpoint.go",
         "wss.go",
     ],
     importpath = "github.com/prysmaticlabs/prysm/beacon-chain/db/kv",
@@ -81,7 +81,6 @@ go_test(
         "checkpoint_test.go",
         "deposit_contract_test.go",
         "encoding_test.go",
-        "error_test.go",
         "finalized_block_roots_test.go",
         "genesis_test.go",
         "init_test.go",
@@ -93,7 +92,7 @@ go_test(
         "state_summary_test.go",
         "state_test.go",
         "utils_test.go",
-        "validated_tips_test.go",
+        "validated_checkpoint_test.go",
     ],
     data = glob(["testdata/**"]),
     embed = [":go_default_library"],
@@ -116,6 +115,7 @@ go_test(
         "//testing/util:go_default_library",
         "@com_github_ethereum_go_ethereum//common:go_default_library",
         "@com_github_golang_snappy//:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
         "@com_github_prysmaticlabs_eth2_types//:go_default_library",
         "@io_bazel_rules_go//go/tools/bazel:go_default_library",
         "@io_etcd_go_bbolt//:go_default_library",

beacon-chain/db/kv/blocks.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/golang/snappy"
 	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
@@ -392,6 +393,44 @@ func (s *Store) HighestSlotBlocksBelow(ctx context.Context, slot types.Slot) ([]
 	return []block.SignedBeaconBlock{blk}, nil
 }
 
+// FeeRecipientByValidatorID returns the fee recipient for a validator id.
+// `ErrNotFoundFeeRecipient` is returned if the validator id is not found.
+func (s *Store) FeeRecipientByValidatorID(ctx context.Context, id types.ValidatorIndex) (common.Address, error) {
+	ctx, span := trace.StartSpan(ctx, "BeaconDB.FeeRecipientByValidatorID")
+	defer span.End()
+	var addr []byte
+	err := s.db.View(func(tx *bolt.Tx) error {
+		bkt := tx.Bucket(feeRecipientBucket)
+		addr = bkt.Get(bytesutil.Uint64ToBytesBigEndian(uint64(id)))
+		if addr == nil {
+			return errors.Wrapf(ErrNotFoundFeeRecipient, "validator id %d", id)
+		}
+		return nil
+	})
+	return common.BytesToAddress(addr), err
+}
+
+// SaveFeeRecipientsByValidatorIDs saves the fee recipients for validator ids.
+// Error is returned if `ids` and `recipients` are not the same length.
+func (s *Store) SaveFeeRecipientsByValidatorIDs(ctx context.Context, ids []types.ValidatorIndex, feeRecipients []common.Address) error {
+	_, span := trace.StartSpan(ctx, "BeaconDB.SaveFeeRecipientByValidatorID")
+	defer span.End()
+
+	if len(ids) != len(feeRecipients) {
+		return errors.New("validatorIDs and feeRecipients must be the same length")
+	}
+
+	return s.db.Update(func(tx *bolt.Tx) error {
+		bkt := tx.Bucket(feeRecipientBucket)
+		for i, id := range ids {
+			if err := bkt.Put(bytesutil.Uint64ToBytesBigEndian(uint64(id)), feeRecipients[i].Bytes()); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+}
+
 // blockRootsByFilter retrieves the block roots given the filter criteria.
 func blockRootsByFilter(ctx context.Context, tx *bolt.Tx, f *filters.QueryFilter) ([][]byte, error) {
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.blockRootsByFilter")

beacon-chain/db/kv/blocks_test.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"testing"
 
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/pkg/errors"
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db/filters"
 	"github.com/prysmaticlabs/prysm/config/params"
@@ -589,3 +591,27 @@ func TestStore_BlocksBySlot_BlockRootsBySlot(t *testing.T) {
 		})
 	}
 }
+
+func TestStore_FeeRecipientByValidatorID(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+	ids := []types.ValidatorIndex{0, 0, 0}
+	feeRecipients := []common.Address{{}, {}, {}, {}}
+	require.ErrorContains(t, "validatorIDs and feeRecipients must be the same length", db.SaveFeeRecipientsByValidatorIDs(ctx, ids, feeRecipients))
+
+	ids = []types.ValidatorIndex{0, 1, 2}
+	feeRecipients = []common.Address{{'a'}, {'b'}, {'c'}}
+	require.NoError(t, db.SaveFeeRecipientsByValidatorIDs(ctx, ids, feeRecipients))
+	f, err := db.FeeRecipientByValidatorID(ctx, 0)
+	require.NoError(t, err)
+	require.Equal(t, common.Address{'a'}, f)
+	f, err = db.FeeRecipientByValidatorID(ctx, 1)
+	require.NoError(t, err)
+	require.Equal(t, common.Address{'b'}, f)
+	f, err = db.FeeRecipientByValidatorID(ctx, 2)
+	require.NoError(t, err)
+	require.Equal(t, common.Address{'c'}, f)
+	_, err = db.FeeRecipientByValidatorID(ctx, 3)
+	want := errors.Wrap(ErrNotFoundFeeRecipient, "validator id 3")
+	require.Equal(t, want.Error(), err.Error())
+}

beacon-chain/db/kv/error.go

@@ -1,6 +1,6 @@
 package kv
 
-import "errors"
+import "github.com/pkg/errors"
 
 // errDeleteFinalized is raised when we attempt to delete a finalized block/state
 var errDeleteFinalized = errors.New("cannot delete finalized block or state")
@@ -8,42 +8,10 @@ var errDeleteFinalized = errors.New("cannot delete finalized block or state")
 // ErrNotFound can be used directly, or as a wrapped DBError, whenever a db method needs to
 // indicate that a value couldn't be found.
 var ErrNotFound = errors.New("not found in db")
+var ErrNotFoundState = errors.Wrap(ErrNotFound, "state not found")
 
 // ErrNotFoundOriginBlockRoot is an error specifically for the origin block root getter
-var ErrNotFoundOriginBlockRoot = WrapDBError(ErrNotFound, "OriginBlockRoot")
+var ErrNotFoundOriginBlockRoot = errors.Wrap(ErrNotFound, "OriginBlockRoot")
 
-// WrapDBError wraps an error in a DBError. See commentary on DBError for more context.
-func WrapDBError(e error, outer string) error {
-	return DBError{
-		Wraps: e,
-		Outer: errors.New(outer),
-	}
-}
-
-// DBError implements the Error method so that it can be asserted as an error.
-// The Unwrap method supports error wrapping, enabling it to be used with errors.Is/As.
-// The primary use case is to make it simple for database methods to return errors
-// that wrap ErrNotFound, allowing calling code to check for "not found" errors
-// like: `error.Is(err, ErrNotFound)`. This is intended to improve error handling
-// in db lookup methods that need to differentiate between a missing value and some
-// other database error. for more background see:
-// https://go.dev/blog/go1.13-errors
-type DBError struct {
-	Wraps error
-	Outer error
-}
-
-// Error satisfies the error interface, so that DBErrors can be used anywhere that
-// expects an `error`.
-func (e DBError) Error() string {
-	es := e.Outer.Error()
-	if e.Wraps != nil {
-		es += ": " + e.Wraps.Error()
-	}
-	return es
-}
-
-// Unwrap is used by the errors package Is and As methods.
-func (e DBError) Unwrap() error {
-	return e.Wraps
-}
+// ErrNotFoundFeeRecipient is a not found error specifically for the fee recipient getter
+var ErrNotFoundFeeRecipient = errors.Wrap(ErrNotFound, "fee recipient")

beacon-chain/db/kv/error_test.go

@@ -1,24 +0,0 @@
-package kv
-
-import (
-	"errors"
-	"testing"
-)
-
-func TestWrappedSentinelError(t *testing.T) {
-	e := ErrNotFoundOriginBlockRoot
-	if !errors.Is(e, ErrNotFoundOriginBlockRoot) {
-		t.Error("expected that a copy of ErrNotFoundOriginBlockRoot would have an is-a relationship")
-	}
-
-	outer := errors.New("wrapped error")
-	e2 := DBError{Wraps: ErrNotFoundOriginBlockRoot, Outer: outer}
-	if !errors.Is(e2, ErrNotFoundOriginBlockRoot) {
-		t.Error("expected that errors.Is would know DBError wraps ErrNotFoundOriginBlockRoot")
-	}
-
-	// test that the innermost not found error is detected
-	if !errors.Is(e2, ErrNotFound) {
-		t.Error("expected that errors.Is would know ErrNotFoundOriginBlockRoot wraps ErrNotFound")
-	}
-}

beacon-chain/db/kv/kv.go

@@ -175,7 +175,6 @@ func NewKVStore(ctx context.Context, dirPath string, config *Config) (*Store, er
 			powchainBucket,
 			stateSummaryBucket,
 			stateValidatorsBucket,
-			validatedTips,
 			// Indices buckets.
 			attestationHeadBlockRootBucket,
 			attestationSourceRootIndicesBucket,
@@ -191,6 +190,8 @@ func NewKVStore(ctx context.Context, dirPath string, config *Config) (*Store, er
 			newStateServiceCompatibleBucket,
 			// Migrations
 			migrationsBucket,
+
+			feeRecipientBucket,
 		)
 	}); err != nil {
 		log.WithField("elapsed", time.Since(start)).Error("Failed to update db and create buckets")

beacon-chain/db/kv/schema.go

@@ -18,7 +18,7 @@ var (
 	checkpointBucket        = []byte("check-point")
 	powchainBucket          = []byte("powchain")
 	stateValidatorsBucket   = []byte("state-validators")
-	validatedTips           = []byte("validated-synced-tips")
+	feeRecipientBucket      = []byte("fee-recipient")
 
 	// Deprecated: This bucket was migrated in PR 6461. Do not use, except for migrations.
 	slotsHasObjectBucket = []byte("slots-has-objects")
@@ -38,12 +38,13 @@ var (
 	blockRootValidatorHashesBucket      = []byte("block-root-validator-hashes")
 
 	// Specific item keys.
-	headBlockRootKey          = []byte("head-root")
-	genesisBlockRootKey       = []byte("genesis-root")
-	depositContractAddressKey = []byte("deposit-contract")
-	justifiedCheckpointKey    = []byte("justified-checkpoint")
-	finalizedCheckpointKey    = []byte("finalized-checkpoint")
-	powchainDataKey           = []byte("powchain-data")
+	headBlockRootKey           = []byte("head-root")
+	genesisBlockRootKey        = []byte("genesis-root")
+	depositContractAddressKey  = []byte("deposit-contract")
+	justifiedCheckpointKey     = []byte("justified-checkpoint")
+	finalizedCheckpointKey     = []byte("finalized-checkpoint")
+	powchainDataKey            = []byte("powchain-data")
+	lastValidatedCheckpointKey = []byte("last-validated-checkpoint")
 
 	// Below keys are used to identify objects are to be fork compatible.
 	// Objects that are only compatible with specific forks should be prefixed with such keys.

beacon-chain/db/kv/state.go

@@ -3,6 +3,7 @@ package kv
 import (
 	"bytes"
 	"context"
+	"fmt"
 
 	"github.com/golang/snappy"
 	"github.com/pkg/errors"
@@ -46,6 +47,19 @@ func (s *Store) State(ctx context.Context, blockRoot [32]byte) (state.BeaconStat
 	return s.unmarshalState(ctx, enc, valEntries)
 }
 
+// StateOrError is just like State(), except it only returns a non-error response
+// if the requested state is found in the database.
+func (s *Store) StateOrError(ctx context.Context, blockRoot [32]byte) (state.BeaconState, error) {
+	st, err := s.State(ctx, blockRoot)
+	if err != nil {
+		return nil, err
+	}
+	if st == nil || st.IsNil() {
+		return nil, errors.Wrap(ErrNotFoundState, fmt.Sprintf("no state with blockroot=%#x", blockRoot))
+	}
+	return st, nil
+}
+
 // GenesisState returns the genesis state in beacon chain.
 func (s *Store) GenesisState(ctx context.Context) (state.BeaconState, error) {
 	ctx, span := trace.StartSpan(ctx, "BeaconDB.GenesisState")

beacon-chain/db/kv/state_test.go

@@ -21,6 +21,12 @@ import (
 	bolt "go.etcd.io/bbolt"
 )
 
+func TestStateNil(t *testing.T) {
+	db := setupDB(t)
+	_, err := db.StateOrError(context.Background(), [32]byte{})
+	require.ErrorIs(t, err, ErrNotFoundState)
+}
+
 func TestState_CanSaveRetrieve(t *testing.T) {
 	db := setupDB(t)
 

beacon-chain/db/kv/validated_checkpoint.go

@@ -0,0 +1,49 @@
+package kv
+
+import (
+	"context"
+
+	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	bolt "go.etcd.io/bbolt"
+	"go.opencensus.io/trace"
+)
+
+// LastValidatedCheckpoint returns the latest fully validated checkpoint in beacon chain.
+func (s *Store) LastValidatedCheckpoint(ctx context.Context) (*ethpb.Checkpoint, error) {
+	ctx, span := trace.StartSpan(ctx, "BeaconDB.LastValidatedCheckpoint")
+	defer span.End()
+	var checkpoint *ethpb.Checkpoint
+	err := s.db.View(func(tx *bolt.Tx) error {
+		bkt := tx.Bucket(checkpointBucket)
+		enc := bkt.Get(lastValidatedCheckpointKey)
+		if enc == nil {
+			var finErr error
+			checkpoint, finErr = s.FinalizedCheckpoint(ctx)
+			return finErr
+		}
+		checkpoint = &ethpb.Checkpoint{}
+		return decode(ctx, enc, checkpoint)
+	})
+	return checkpoint, err
+}
+
+// SaveLastValidatedCheckpoint saves the last validated checkpoint in beacon chain.
+func (s *Store) SaveLastValidatedCheckpoint(ctx context.Context, checkpoint *ethpb.Checkpoint) error {
+	ctx, span := trace.StartSpan(ctx, "BeaconDB.SaveLastValidatedCheckpoint")
+	defer span.End()
+
+	enc, err := encode(ctx, checkpoint)
+	if err != nil {
+		return err
+	}
+	return s.db.Update(func(tx *bolt.Tx) error {
+		bucket := tx.Bucket(checkpointBucket)
+		hasStateSummary := s.hasStateSummaryBytes(tx, bytesutil.ToBytes32(checkpoint.Root))
+		hasStateInDB := tx.Bucket(stateBucket).Get(checkpoint.Root) != nil
+		if !(hasStateInDB || hasStateSummary) {
+			return errMissingStateForCheckpoint
+		}
+		return bucket.Put(lastValidatedCheckpointKey, enc)
+	})
+}

beacon-chain/db/kv/validated_checkpoint_test.go

@@ -0,0 +1,67 @@
+package kv
+
+import (
+	"context"
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
+	ethpb "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1/wrapper"
+	"github.com/prysmaticlabs/prysm/testing/assert"
+	"github.com/prysmaticlabs/prysm/testing/require"
+	"github.com/prysmaticlabs/prysm/testing/util"
+	"google.golang.org/protobuf/proto"
+)
+
+func TestStore_LastValidatedCheckpoint_CanSaveRetrieve(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+	root := bytesutil.ToBytes32([]byte{'A'})
+	cp := &ethpb.Checkpoint{
+		Epoch: 10,
+		Root:  root[:],
+	}
+	st, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, st.SetSlot(1))
+	require.NoError(t, db.SaveState(ctx, st, root))
+	require.NoError(t, db.SaveLastValidatedCheckpoint(ctx, cp))
+
+	retrieved, err := db.LastValidatedCheckpoint(ctx)
+	require.NoError(t, err)
+	assert.Equal(t, true, proto.Equal(cp, retrieved), "Wanted %v, received %v", cp, retrieved)
+}
+
+func TestStore_LastValidatedCheckpoint_DefaultIsFinalized(t *testing.T) {
+	db := setupDB(t)
+	ctx := context.Background()
+
+	genesis := bytesutil.ToBytes32([]byte{'G', 'E', 'N', 'E', 'S', 'I', 'S'})
+	require.NoError(t, db.SaveGenesisBlockRoot(ctx, genesis))
+
+	blk := util.NewBeaconBlock()
+	blk.Block.ParentRoot = genesis[:]
+	blk.Block.Slot = 40
+
+	root, err := blk.Block.HashTreeRoot()
+	require.NoError(t, err)
+
+	cp := &ethpb.Checkpoint{
+		Epoch: 5,
+		Root:  root[:],
+	}
+
+	// a valid chain is required to save finalized checkpoint.
+	require.NoError(t, db.SaveBlock(ctx, wrapper.WrappedPhase0SignedBeaconBlock(blk)))
+	st, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, st.SetSlot(1))
+	// a state is required to save checkpoint
+	require.NoError(t, db.SaveState(ctx, st, root))
+
+	require.NoError(t, db.SaveFinalizedCheckpoint(ctx, cp))
+
+	retrieved, err := db.LastValidatedCheckpoint(ctx)
+	require.NoError(t, err)
+	assert.Equal(t, true, proto.Equal(cp, retrieved), "Wanted %v, received %v", cp, retrieved)
+}

beacon-chain/db/kv/validated_tips.go

@@ -1,71 +0,0 @@
-package kv
-
-import (
-	"context"
-
-	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
-	bolt "go.etcd.io/bbolt"
-	"go.opencensus.io/trace"
-)
-
-// ValidatedTips returns all the validated_tips that are present in the DB.
-func (s *Store) ValidatedTips(ctx context.Context) (map[[32]byte]types.Slot, error) {
-	ctx, span := trace.StartSpan(ctx, "BeaconDB.ValidatedTips")
-	defer span.End()
-
-	valTips := make(map[[32]byte]types.Slot, 1)
-	err := s.db.View(func(tx *bolt.Tx) error {
-		bkt := tx.Bucket(validatedTips)
-
-		c := bkt.Cursor()
-		for k, v := c.First(); k != nil; k, v = c.Next() {
-			if ctx.Err() != nil {
-				return ctx.Err()
-			}
-			valTips[bytesutil.ToBytes32(k)] = bytesutil.BytesToSlotBigEndian(v)
-		}
-		return nil
-	})
-	return valTips, err
-}
-
-// UpdateValidatedTips clears off all the old validated_tips from the DB and
-// adds the new tips that are provided.
-func (s *Store) UpdateValidatedTips(ctx context.Context, newVals map[[32]byte]types.Slot) error {
-	ctx, span := trace.StartSpan(ctx, "BeaconDB.UpdateValidatedTips")
-	defer span.End()
-
-	// Get the already existing tips.
-	oldVals, err := s.ValidatedTips(ctx)
-	if err != nil {
-		return err
-	}
-
-	updateErr := s.db.Update(func(tx *bolt.Tx) error {
-		bkt := tx.Bucket(validatedTips)
-
-		// Delete keys that are present and not in the new set.
-		for k := range oldVals {
-			if _, ok := newVals[k]; !ok {
-				deleteErr := bkt.Delete(k[:])
-				if deleteErr != nil {
-					return deleteErr
-				}
-
-			}
-		}
-
-		// Add keys not present already.
-		for k, v := range newVals {
-			if _, ok := oldVals[k]; !ok {
-				putErr := bkt.Put(k[:], bytesutil.SlotToBytesBigEndian(v))
-				if putErr != nil {
-					return putErr
-				}
-			}
-		}
-		return nil
-	})
-	return updateErr
-}

beacon-chain/db/kv/validated_tips_test.go

@@ -1,93 +0,0 @@
-package kv
-
-import (
-	"context"
-	"testing"
-
-	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/testing/require"
-)
-
-func TestTips_AddNewTips(t *testing.T) {
-	ctx := context.Background()
-	db := setupDB(t)
-
-	newTips := make(map[[32]byte]types.Slot)
-	newTips[[32]byte{'A'}] = types.Slot(1)
-	newTips[[32]byte{'B'}] = types.Slot(2)
-	newTips[[32]byte{'C'}] = types.Slot(3)
-
-	require.NoError(t, db.UpdateValidatedTips(ctx, newTips))
-
-	gotTips, err := db.ValidatedTips(ctx)
-	require.NoError(t, err)
-
-	require.Equal(t, true, areTipsSame(gotTips, newTips))
-}
-
-func TestTips_UpdateTipsWithoutOverlap(t *testing.T) {
-	ctx := context.Background()
-	db := setupDB(t)
-
-	oldTips := make(map[[32]byte]types.Slot)
-	oldTips[[32]byte{'A'}] = types.Slot(1)
-	oldTips[[32]byte{'B'}] = types.Slot(2)
-	oldTips[[32]byte{'C'}] = types.Slot(3)
-
-	require.NoError(t, db.UpdateValidatedTips(ctx, oldTips))
-
-	// create a new non-overlapping tips to add
-	newTips := make(map[[32]byte]types.Slot)
-	newTips[[32]byte{'D'}] = types.Slot(4)
-	newTips[[32]byte{'E'}] = types.Slot(5)
-	newTips[[32]byte{'F'}] = types.Slot(6)
-
-	require.NoError(t, db.UpdateValidatedTips(ctx, newTips))
-
-	gotTips, err := db.ValidatedTips(ctx)
-	require.NoError(t, err)
-
-	require.Equal(t, true, areTipsSame(gotTips, newTips))
-
-}
-
-func TestTips_UpdateTipsWithOverlap(t *testing.T) {
-	ctx := context.Background()
-	db := setupDB(t)
-
-	oldTips := make(map[[32]byte]types.Slot)
-	oldTips[[32]byte{'A'}] = types.Slot(1)
-	oldTips[[32]byte{'B'}] = types.Slot(2)
-	oldTips[[32]byte{'C'}] = types.Slot(3)
-	require.NoError(t, db.UpdateValidatedTips(ctx, oldTips))
-
-	// create a new overlapping tips to add
-	newTips := make(map[[32]byte]types.Slot)
-	newTips[[32]byte{'C'}] = types.Slot(3)
-	newTips[[32]byte{'D'}] = types.Slot(4)
-	newTips[[32]byte{'E'}] = types.Slot(5)
-	require.NoError(t, db.UpdateValidatedTips(ctx, newTips))
-
-	gotTips, err := db.ValidatedTips(ctx)
-	require.NoError(t, err)
-
-	require.Equal(t, true, areTipsSame(gotTips, newTips))
-
-}
-
-func areTipsSame(got map[[32]byte]types.Slot, required map[[32]byte]types.Slot) bool {
-	if len(got) != len(required) {
-		return false
-	}
-
-	for k, v := range got {
-		if val, ok := required[k]; ok {
-			if uint64(v) != uint64(val) {
-				return false
-			}
-		} else {
-			return false
-		}
-	}
-	return true
-}

beacon-chain/forkchoice/BUILD.bazel

@@ -12,7 +12,8 @@ go_library(
         "//testing/spectest:__subpackages__",
     ],
     deps = [
-        "//beacon-chain/forkchoice/protoarray:go_default_library",
+        "//config/fieldparams:go_default_library",
+        "//proto/prysm/v1alpha1:go_default_library",
         "@com_github_prysmaticlabs_eth2_types//:go_default_library",
     ],
 )

beacon-chain/forkchoice/doubly-linked-tree/BUILD.bazel

@@ -0,0 +1,55 @@
+load("@prysm//tools/go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "doc.go",
+        "errors.go",
+        "forkchoice.go",
+        "metrics.go",
+        "node.go",
+        "optimistic_sync.go",
+        "proposer_boost.go",
+        "store.go",
+        "types.go",
+    ],
+    importpath = "github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/doubly-linked-tree",
+    visibility = [
+        "//beacon-chain:__subpackages__",
+        "//testing/spectest:__subpackages__",
+    ],
+    deps = [
+        "//config/fieldparams:go_default_library",
+        "//config/params:go_default_library",
+        "//proto/prysm/v1alpha1:go_default_library",
+        "//time/slots:go_default_library",
+        "@com_github_pkg_errors//:go_default_library",
+        "@com_github_prometheus_client_golang//prometheus:go_default_library",
+        "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
+        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
+        "@io_opencensus_go//trace:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = [
+        "ffg_update_test.go",
+        "forkchoice_test.go",
+        "no_vote_test.go",
+        "node_test.go",
+        "optimistic_sync_test.go",
+        "proposer_boost_test.go",
+        "store_test.go",
+        "vote_test.go",
+    ],
+    embed = [":go_default_library"],
+    deps = [
+        "//config/params:go_default_library",
+        "//crypto/hash:go_default_library",
+        "//encoding/bytesutil:go_default_library",
+        "//testing/assert:go_default_library",
+        "//testing/require:go_default_library",
+        "@com_github_prysmaticlabs_eth2_types//:go_default_library",
+    ],
+)

beacon-chain/forkchoice/doubly-linked-tree/doc.go

@@ -0,0 +1,4 @@
+/*
+Package doublylinkedtree implements eth2 LMD GHOST fork choice using the doubly linked proto array node structure.
+*/
+package doublylinkedtree

beacon-chain/forkchoice/doubly-linked-tree/errors.go

@@ -0,0 +1,10 @@
+package doublylinkedtree
+
+import "errors"
+
+var ErrNilNode = errors.New("invalid nil or unknown node")
+var errInvalidBalance = errors.New("invalid node balance")
+var errInvalidProposerBoostRoot = errors.New("invalid proposer boost root")
+var errUnknownFinalizedRoot = errors.New("unknown finalized root")
+var errUnknownJustifiedRoot = errors.New("unknown justified root")
+var errInvalidOptimisticStatus = errors.New("invalid optimistic status")

beacon-chain/forkchoice/doubly-linked-tree/ffg_update_test.go

@@ -0,0 +1,193 @@
+package doublylinkedtree
+
+import (
+	"context"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/config/params"
+	"github.com/prysmaticlabs/prysm/testing/assert"
+	"github.com/prysmaticlabs/prysm/testing/require"
+)
+
+func TestFFGUpdates_OneBranch(t *testing.T) {
+	balances := []uint64{1, 1}
+	f := setup(0, 0)
+
+	// The head should always start at the finalized block.
+	r, err := f.Head(context.Background(), 0, params.BeaconConfig().ZeroHash, balances, 0)
+	require.NoError(t, err)
+	assert.Equal(t, params.BeaconConfig().ZeroHash, r, "Incorrect head with genesis")
+
+	// Define the following tree:
+	//            0 <- justified: 0, finalized: 0
+	//            |
+	//            1 <- justified: 0, finalized: 0
+	//            |
+	//            2 <- justified: 1, finalized: 0
+	//            |
+	//            3 <- justified: 2, finalized: 1
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 2, indexToHash(2), indexToHash(1), 1, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 3, indexToHash(3), indexToHash(2), 2, 1))
+
+	// With starting justified epoch at 0, the head should be 3:
+	//            0 <- start
+	//            |
+	//            1
+	//            |
+	//            2
+	//            |
+	//            3 <- head
+	r, err = f.Head(context.Background(), 0, params.BeaconConfig().ZeroHash, balances, 0)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(3), r, "Incorrect head for with justified epoch at 0")
+
+	// With starting justified epoch at 1, the head should be 2:
+	//            0
+	//            |
+	//            1 <- start
+	//            |
+	//            2 <- head
+	//            |
+	//            3
+	r, err = f.Head(context.Background(), 1, indexToHash(2), balances, 0)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(2), r, "Incorrect head with justified epoch at 1")
+
+	// With starting justified epoch at 2, the head should be 3:
+	//            0
+	//            |
+	//            1
+	//            |
+	//            2 <- start
+	//            |
+	//            3 <- head
+	r, err = f.Head(context.Background(), 2, indexToHash(3), balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(3), r, "Incorrect head with justified epoch at 2")
+}
+
+func TestFFGUpdates_TwoBranches(t *testing.T) {
+	balances := []uint64{1, 1}
+	f := setup(0, 0)
+
+	r, err := f.Head(context.Background(), 0, params.BeaconConfig().ZeroHash, balances, 0)
+	require.NoError(t, err)
+	assert.Equal(t, params.BeaconConfig().ZeroHash, r, "Incorrect head with genesis")
+
+	// Define the following tree:
+	//                                0
+	//                               / \
+	//  justified: 0, finalized: 0 -> 1   2 <- justified: 0, finalized: 0
+	//                              |   |
+	//  justified: 1, finalized: 0 -> 3   4 <- justified: 0, finalized: 0
+	//                              |   |
+	//  justified: 1, finalized: 0 -> 5   6 <- justified: 0, finalized: 0
+	//                              |   |
+	//  justified: 1, finalized: 0 -> 7   8 <- justified: 1, finalized: 0
+	//                              |   |
+	//  justified: 2, finalized: 0 -> 9  10 <- justified: 2, finalized: 0
+	// Left branch.
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 2, indexToHash(3), indexToHash(1), 1, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 3, indexToHash(5), indexToHash(3), 1, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 4, indexToHash(7), indexToHash(5), 1, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 4, indexToHash(9), indexToHash(7), 2, 0))
+	// Right branch.
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 1, indexToHash(2), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 2, indexToHash(4), indexToHash(2), 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 3, indexToHash(6), indexToHash(4), 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 4, indexToHash(8), indexToHash(6), 1, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 4, indexToHash(10), indexToHash(8), 2, 0))
+
+	// With start at 0, the head should be 10:
+	//           0  <-- start
+	//          / \
+	//         1   2
+	//         |   |
+	//         3   4
+	//         |   |
+	//         5   6
+	//         |   |
+	//         7   8
+	//         |   |
+	//         9  10 <-- head
+	r, err = f.Head(context.Background(), 0, params.BeaconConfig().ZeroHash, balances, 0)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(10), r, "Incorrect head with justified epoch at 0")
+
+	// Add a vote to 1:
+	//                 0
+	//                / \
+	//    +1 vote -> 1   2
+	//               |   |
+	//               3   4
+	//               |   |
+	//               5   6
+	//               |   |
+	//               7   8
+	//               |   |
+	//               9  10
+	f.ProcessAttestation(context.Background(), []uint64{0}, indexToHash(1), 0)
+
+	// With the additional vote to the left branch, the head should be 9:
+	//           0  <-- start
+	//          / \
+	//         1   2
+	//         |   |
+	//         3   4
+	//         |   |
+	//         5   6
+	//         |   |
+	//         7   8
+	//         |   |
+	// head -> 9  10
+	r, err = f.Head(context.Background(), 0, params.BeaconConfig().ZeroHash, balances, 0)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(9), r, "Incorrect head with justified epoch at 0")
+
+	// Add a vote to 2:
+	//                 0
+	//                / \
+	//               1   2 <- +1 vote
+	//               |   |
+	//               3   4
+	//               |   |
+	//               5   6
+	//               |   |
+	//               7   8
+	//               |   |
+	//               9  10
+	f.ProcessAttestation(context.Background(), []uint64{1}, indexToHash(2), 0)
+
+	// With the additional vote to the right branch, the head should be 10:
+	//           0  <-- start
+	//          / \
+	//         1   2
+	//         |   |
+	//         3   4
+	//         |   |
+	//         5   6
+	//         |   |
+	//         7   8
+	//         |   |
+	//         9  10 <-- head
+	r, err = f.Head(context.Background(), 0, params.BeaconConfig().ZeroHash, balances, 0)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(10), r, "Incorrect head with justified epoch at 0")
+
+	r, err = f.Head(context.Background(), 1, indexToHash(1), balances, 0)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(7), r, "Incorrect head with justified epoch at 0")
+}
+
+func setup(justifiedEpoch, finalizedEpoch types.Epoch) *ForkChoice {
+	ctx := context.Background()
+	f := New(justifiedEpoch, finalizedEpoch)
+	err := f.InsertOptimisticBlock(ctx, 0, params.BeaconConfig().ZeroHash, [32]byte{}, justifiedEpoch, finalizedEpoch)
+	if err != nil {
+		return nil
+	}
+	return f
+}

beacon-chain/forkchoice/doubly-linked-tree/forkchoice.go

@@ -0,0 +1,307 @@
+package doublylinkedtree
+
+import (
+	"context"
+
+	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
+	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
+	"github.com/prysmaticlabs/prysm/config/params"
+	pbrpc "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+	"go.opencensus.io/trace"
+)
+
+// New initializes a new fork choice store.
+func New(justifiedEpoch, finalizedEpoch types.Epoch) *ForkChoice {
+	s := &Store{
+		justifiedEpoch:    justifiedEpoch,
+		finalizedEpoch:    finalizedEpoch,
+		proposerBoostRoot: [32]byte{},
+		nodeByRoot:        make(map[[fieldparams.RootLength]byte]*Node),
+		pruneThreshold:    defaultPruneThreshold,
+	}
+
+	b := make([]uint64, 0)
+	v := make([]Vote, 0)
+	return &ForkChoice{store: s, balances: b, votes: v}
+}
+
+// NodeCount returns the current number of nodes in the Store.
+func (f *ForkChoice) NodeCount() int {
+	f.store.nodesLock.RLock()
+	defer f.store.nodesLock.RUnlock()
+	return len(f.store.nodeByRoot)
+}
+
+// Head returns the head root from fork choice store.
+// It firsts computes validator's balance changes then recalculates block tree from leaves to root.
+func (f *ForkChoice) Head(
+	ctx context.Context,
+	justifiedEpoch types.Epoch,
+	justifiedRoot [32]byte,
+	justifiedStateBalances []uint64,
+	finalizedEpoch types.Epoch,
+) ([32]byte, error) {
+	ctx, span := trace.StartSpan(ctx, "doublyLinkedForkchoice.Head")
+	defer span.End()
+	f.votesLock.Lock()
+	defer f.votesLock.Unlock()
+
+	calledHeadCount.Inc()
+
+	// Using the write lock here because `applyWeightChanges` that gets called subsequently requires a write operation.
+	f.store.nodesLock.Lock()
+	defer f.store.nodesLock.Unlock()
+
+	f.store.updateCheckpoints(justifiedEpoch, finalizedEpoch)
+
+	if err := f.updateBalances(justifiedStateBalances); err != nil {
+		return [32]byte{}, errors.Wrap(err, "could not update balances")
+	}
+
+	if err := f.store.applyProposerBoostScore(justifiedStateBalances); err != nil {
+		return [32]byte{}, errors.Wrap(err, "could not apply proposer boost score")
+	}
+
+	if err := f.store.treeRootNode.applyWeightChanges(ctx); err != nil {
+		return [32]byte{}, errors.Wrap(err, "could not apply weight changes")
+	}
+
+	if err := f.store.treeRootNode.updateBestDescendant(ctx, justifiedEpoch, finalizedEpoch); err != nil {
+		return [32]byte{}, errors.Wrap(err, "could not update best descendant")
+	}
+
+	return f.store.head(ctx, justifiedRoot)
+}
+
+// ProcessAttestation processes attestation for vote accounting, it iterates around validator indices
+// and update their votes accordingly.
+func (f *ForkChoice) ProcessAttestation(ctx context.Context, validatorIndices []uint64, blockRoot [32]byte, targetEpoch types.Epoch) {
+	_, span := trace.StartSpan(ctx, "doublyLinkedForkchoice.ProcessAttestation")
+	defer span.End()
+	f.votesLock.Lock()
+	defer f.votesLock.Unlock()
+
+	for _, index := range validatorIndices {
+		// Validator indices will grow the vote cache.
+		for index >= uint64(len(f.votes)) {
+			f.votes = append(f.votes, Vote{currentRoot: params.BeaconConfig().ZeroHash, nextRoot: params.BeaconConfig().ZeroHash})
+		}
+
+		// Newly allocated vote if the root fields are untouched.
+		newVote := f.votes[index].nextRoot == params.BeaconConfig().ZeroHash &&
+			f.votes[index].currentRoot == params.BeaconConfig().ZeroHash
+
+		// Vote gets updated if it's newly allocated or high target epoch.
+		if newVote || targetEpoch > f.votes[index].nextEpoch {
+			f.votes[index].nextEpoch = targetEpoch
+			f.votes[index].nextRoot = blockRoot
+		}
+	}
+
+	processedAttestationCount.Inc()
+}
+
+// InsertOptimisticBlock processes a new block by inserting it to the fork choice store.
+func (f *ForkChoice) InsertOptimisticBlock(
+	ctx context.Context,
+	slot types.Slot,
+	blockRoot, parentRoot [fieldparams.RootLength]byte,
+	justifiedEpoch, finalizedEpoch types.Epoch,
+) error {
+	ctx, span := trace.StartSpan(ctx, "doublyLinkedForkchoice.InsertOptimisticBlock")
+	defer span.End()
+
+	return f.store.insert(ctx, slot, blockRoot, parentRoot, justifiedEpoch, finalizedEpoch)
+}
+
+// Prune prunes the fork choice store with the new finalized root. The store is only pruned if the input
+// root is different than the current store finalized root, and the number of the store has met prune threshold.
+func (f *ForkChoice) Prune(ctx context.Context, finalizedRoot [32]byte) error {
+	return f.store.prune(ctx, finalizedRoot)
+}
+
+// HasNode returns true if the node exists in fork choice store,
+// false else wise.
+func (f *ForkChoice) HasNode(root [32]byte) bool {
+	f.store.nodesLock.RLock()
+	defer f.store.nodesLock.RUnlock()
+
+	_, ok := f.store.nodeByRoot[root]
+	return ok
+}
+
+// HasParent returns true if the node parent exists in fork choice store,
+// false else wise.
+func (f *ForkChoice) HasParent(root [32]byte) bool {
+	f.store.nodesLock.RLock()
+	defer f.store.nodesLock.RUnlock()
+
+	node, ok := f.store.nodeByRoot[root]
+	if !ok || node == nil {
+		return false
+	}
+
+	return node.parent != nil
+}
+
+// IsCanonical returns true if the given root is part of the canonical chain.
+func (f *ForkChoice) IsCanonical(root [32]byte) bool {
+	f.store.nodesLock.RLock()
+	defer f.store.nodesLock.RUnlock()
+
+	node, ok := f.store.nodeByRoot[root]
+	if !ok || node == nil {
+		return false
+	}
+
+	if node.bestDescendant == nil {
+		if f.store.headNode.bestDescendant == nil {
+			return node == f.store.headNode
+		}
+		return node == f.store.headNode.bestDescendant
+	}
+	if f.store.headNode.bestDescendant == nil {
+		return node.bestDescendant == f.store.headNode
+	}
+	return node.bestDescendant == f.store.headNode.bestDescendant
+}
+
+// IsOptimistic returns true if the given root has been optimistically synced.
+func (f *ForkChoice) IsOptimistic(_ context.Context, root [32]byte) (bool, error) {
+	f.store.nodesLock.RLock()
+	defer f.store.nodesLock.RUnlock()
+
+	node, ok := f.store.nodeByRoot[root]
+	if !ok || node == nil {
+		return false, ErrNilNode
+	}
+
+	return node.optimistic, nil
+}
+
+// AncestorRoot returns the ancestor root of input block root at a given slot.
+func (f *ForkChoice) AncestorRoot(ctx context.Context, root [32]byte, slot types.Slot) ([]byte, error) {
+	ctx, span := trace.StartSpan(ctx, "protoArray.AncestorRoot")
+	defer span.End()
+
+	f.store.nodesLock.RLock()
+	defer f.store.nodesLock.RUnlock()
+
+	node, ok := f.store.nodeByRoot[root]
+	if !ok || node == nil {
+		return nil, ErrNilNode
+	}
+
+	n := node
+	for n != nil && n.slot > slot {
+		if ctx.Err() != nil {
+			return nil, ctx.Err()
+		}
+		n = n.parent
+	}
+
+	if n == nil {
+		return nil, ErrNilNode
+	}
+
+	return n.root[:], nil
+}
+
+// updateBalances updates the balances that directly voted for each block taking into account the
+// validators' latest votes.
+func (f *ForkChoice) updateBalances(newBalances []uint64) error {
+	for index, vote := range f.votes {
+		// Skip if validator has never voted for current root and next root (i.e. if the
+		// votes are zero hash aka genesis block), there's nothing to compute.
+		if vote.currentRoot == params.BeaconConfig().ZeroHash && vote.nextRoot == params.BeaconConfig().ZeroHash {
+			continue
+		}
+
+		oldBalance := uint64(0)
+		newBalance := uint64(0)
+		// If the validator index did not exist in `f.balances` or
+		// `newBalances` list above, the balance is just 0.
+		if index < len(f.balances) {
+			oldBalance = f.balances[index]
+		}
+		if index < len(newBalances) {
+			newBalance = newBalances[index]
+		}
+
+		// Update only if the validator's balance or vote has changed.
+		if vote.currentRoot != vote.nextRoot || oldBalance != newBalance {
+			// Ignore the vote if the root is not in fork choice
+			// store, that means we have not seen the block before.
+			nextNode, ok := f.store.nodeByRoot[vote.nextRoot]
+			if ok && vote.nextRoot != params.BeaconConfig().ZeroHash {
+				// Protection against nil node
+				if nextNode == nil {
+					return ErrNilNode
+				}
+				nextNode.balance += newBalance
+			}
+
+			currentNode, ok := f.store.nodeByRoot[vote.currentRoot]
+			if ok && vote.currentRoot != params.BeaconConfig().ZeroHash {
+				// Protection against nil node
+				if currentNode == nil {
+					return ErrNilNode
+				}
+				if currentNode.balance < oldBalance {
+					return errInvalidBalance
+				}
+				currentNode.balance -= oldBalance
+			}
+		}
+
+		// Rotate the validator vote.
+		f.votes[index].currentRoot = vote.nextRoot
+	}
+	f.balances = newBalances
+	return nil
+}
+
+// Tips returns a list of possible heads from fork choice store, it returns the
+// roots and the slots of the leaf nodes.
+func (f *ForkChoice) Tips() ([][32]byte, []types.Slot) {
+	return f.store.tips()
+}
+
+// ProposerBoost returns the proposerBoost of the store
+func (f *ForkChoice) ProposerBoost() [fieldparams.RootLength]byte {
+	return f.store.proposerBoost()
+}
+
+// SetOptimisticToValid sets the node with the given root as a fully validated node
+func (f *ForkChoice) SetOptimisticToValid(ctx context.Context, root [fieldparams.RootLength]byte) error {
+	f.store.nodesLock.Lock()
+	defer f.store.nodesLock.Unlock()
+	node, ok := f.store.nodeByRoot[root]
+	if !ok || node == nil {
+		return ErrNilNode
+	}
+	return node.setNodeAndParentValidated(ctx)
+}
+
+// JustifiedEpoch of fork choice store.
+func (f *ForkChoice) JustifiedEpoch() types.Epoch {
+	return f.store.justifiedEpoch
+}
+
+// FinalizedEpoch of fork choice store.
+func (f *ForkChoice) FinalizedEpoch() types.Epoch {
+	return f.store.finalizedEpoch
+}
+
+func (f *ForkChoice) ForkChoiceNodes() []*pbrpc.ForkChoiceNode {
+	f.store.nodesLock.RLock()
+	defer f.store.nodesLock.RUnlock()
+	ret := make([]*pbrpc.ForkChoiceNode, len(f.store.nodeByRoot))
+	return f.store.treeRootNode.rpcNodes(ret)
+}
+
+// SetOptimisticToInvalid removes a block with an invalid execution payload from fork choice store
+func (f *ForkChoice) SetOptimisticToInvalid(ctx context.Context, root [fieldparams.RootLength]byte) error {
+	return f.store.removeNode(ctx, root)
+}

beacon-chain/forkchoice/doubly-linked-tree/forkchoice_test.go

@@ -0,0 +1,168 @@
+package doublylinkedtree
+
+import (
+	"context"
+	"encoding/binary"
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/config/params"
+	"github.com/prysmaticlabs/prysm/crypto/hash"
+	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
+	"github.com/prysmaticlabs/prysm/testing/assert"
+	"github.com/prysmaticlabs/prysm/testing/require"
+)
+
+func TestForkChoice_UpdateBalancesPositiveChange(t *testing.T) {
+	f := setup(0, 0)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), indexToHash(1), 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 3, indexToHash(3), indexToHash(2), 0, 0))
+
+	f.votes = []Vote{
+		{indexToHash(1), indexToHash(1), 0},
+		{indexToHash(2), indexToHash(2), 0},
+		{indexToHash(3), indexToHash(3), 0},
+	}
+
+	// Each node gets one unique vote. The weight should look like 103 <- 102 <- 101 because
+	// they get propagated back.
+	require.NoError(t, f.updateBalances([]uint64{10, 20, 30}))
+	s := f.store
+	assert.Equal(t, uint64(10), s.nodeByRoot[indexToHash(1)].balance)
+	assert.Equal(t, uint64(20), s.nodeByRoot[indexToHash(2)].balance)
+	assert.Equal(t, uint64(30), s.nodeByRoot[indexToHash(3)].balance)
+}
+
+func TestForkChoice_UpdateBalancesNegativeChange(t *testing.T) {
+	f := setup(0, 0)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), indexToHash(1), 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 3, indexToHash(3), indexToHash(2), 0, 0))
+	s := f.store
+	s.nodeByRoot[indexToHash(1)].balance = 100
+	s.nodeByRoot[indexToHash(2)].balance = 100
+	s.nodeByRoot[indexToHash(3)].balance = 100
+
+	f.balances = []uint64{100, 100, 100}
+	f.votes = []Vote{
+		{indexToHash(1), indexToHash(1), 0},
+		{indexToHash(2), indexToHash(2), 0},
+		{indexToHash(3), indexToHash(3), 0},
+	}
+
+	require.NoError(t, f.updateBalances([]uint64{10, 20, 30}))
+	assert.Equal(t, uint64(10), s.nodeByRoot[indexToHash(1)].balance)
+	assert.Equal(t, uint64(20), s.nodeByRoot[indexToHash(2)].balance)
+	assert.Equal(t, uint64(30), s.nodeByRoot[indexToHash(3)].balance)
+}
+
+func TestForkChoice_IsCanonical(t *testing.T) {
+	f := setup(1, 1)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 3, indexToHash(3), indexToHash(1), 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 4, indexToHash(4), indexToHash(2), 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 5, indexToHash(5), indexToHash(4), 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 6, indexToHash(6), indexToHash(5), 1, 1))
+
+	require.Equal(t, true, f.IsCanonical(params.BeaconConfig().ZeroHash))
+	require.Equal(t, false, f.IsCanonical(indexToHash(1)))
+	require.Equal(t, true, f.IsCanonical(indexToHash(2)))
+	require.Equal(t, false, f.IsCanonical(indexToHash(3)))
+	require.Equal(t, true, f.IsCanonical(indexToHash(4)))
+	require.Equal(t, true, f.IsCanonical(indexToHash(5)))
+	require.Equal(t, true, f.IsCanonical(indexToHash(6)))
+}
+
+func TestForkChoice_IsCanonicalReorg(t *testing.T) {
+	f := setup(1, 1)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, [32]byte{'1'}, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, [32]byte{'2'}, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 3, [32]byte{'3'}, [32]byte{'1'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 4, [32]byte{'4'}, [32]byte{'2'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 5, [32]byte{'5'}, [32]byte{'4'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 6, [32]byte{'6'}, [32]byte{'5'}, 1, 1))
+
+	f.store.nodesLock.Lock()
+	f.store.nodeByRoot[[32]byte{'3'}].balance = 10
+	require.NoError(t, f.store.treeRootNode.applyWeightChanges(ctx))
+	require.Equal(t, uint64(10), f.store.nodeByRoot[[32]byte{'1'}].weight)
+	require.Equal(t, uint64(0), f.store.nodeByRoot[[32]byte{'2'}].weight)
+
+	require.NoError(t, f.store.treeRootNode.updateBestDescendant(ctx, 1, 1))
+	require.DeepEqual(t, [32]byte{'3'}, f.store.treeRootNode.bestDescendant.root)
+	f.store.nodesLock.Unlock()
+
+	h, err := f.store.head(ctx, [32]byte{'1'})
+	require.NoError(t, err)
+	require.DeepEqual(t, [32]byte{'3'}, h)
+	require.DeepEqual(t, h, f.store.headNode.root)
+
+	require.Equal(t, true, f.IsCanonical(params.BeaconConfig().ZeroHash))
+	require.Equal(t, true, f.IsCanonical([32]byte{'1'}))
+	require.Equal(t, false, f.IsCanonical([32]byte{'2'}))
+	require.Equal(t, true, f.IsCanonical([32]byte{'3'}))
+	require.Equal(t, false, f.IsCanonical([32]byte{'4'}))
+	require.Equal(t, false, f.IsCanonical([32]byte{'5'}))
+	require.Equal(t, false, f.IsCanonical([32]byte{'6'}))
+}
+
+func TestForkChoice_AncestorRoot(t *testing.T) {
+	f := setup(1, 1)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), indexToHash(1), 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 5, indexToHash(3), indexToHash(2), 1, 1))
+	f.store.treeRootNode = f.store.nodeByRoot[indexToHash(1)]
+	f.store.treeRootNode.parent = nil
+
+	r, err := f.AncestorRoot(ctx, indexToHash(3), 6)
+	assert.NoError(t, err)
+	assert.Equal(t, bytesutil.ToBytes32(r), indexToHash(3))
+
+	_, err = f.AncestorRoot(ctx, indexToHash(3), 0)
+	assert.ErrorContains(t, ErrNilNode.Error(), err)
+
+	root, err := f.AncestorRoot(ctx, indexToHash(3), 5)
+	require.NoError(t, err)
+	hash3 := indexToHash(3)
+	require.DeepEqual(t, hash3[:], root)
+	root, err = f.AncestorRoot(ctx, indexToHash(3), 1)
+	require.NoError(t, err)
+	hash1 := indexToHash(1)
+	require.DeepEqual(t, hash1[:], root)
+}
+
+func TestForkChoice_AncestorEqualSlot(t *testing.T) {
+	f := setup(1, 1)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 100, [32]byte{'1'}, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 101, [32]byte{'3'}, [32]byte{'1'}, 1, 1))
+
+	r, err := f.AncestorRoot(ctx, [32]byte{'3'}, 100)
+	require.NoError(t, err)
+	root := bytesutil.ToBytes32(r)
+	require.Equal(t, root, [32]byte{'1'})
+}
+
+func TestForkChoice_AncestorLowerSlot(t *testing.T) {
+	f := setup(1, 1)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 100, [32]byte{'1'}, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 200, [32]byte{'3'}, [32]byte{'1'}, 1, 1))
+
+	r, err := f.AncestorRoot(ctx, [32]byte{'3'}, 150)
+	require.NoError(t, err)
+	root := bytesutil.ToBytes32(r)
+	require.Equal(t, root, [32]byte{'1'})
+}
+
+func indexToHash(i uint64) [32]byte {
+	var b [8]byte
+	binary.LittleEndian.PutUint64(b[:], i)
+	return hash.Hash(b[:])
+}

beacon-chain/forkchoice/doubly-linked-tree/metrics.go

@@ -0,0 +1,57 @@
+package doublylinkedtree
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var (
+	headSlotNumber = promauto.NewGauge(
+		prometheus.GaugeOpts{
+			Name: "doublylinkedtree_head_slot",
+			Help: "The slot number of the current head.",
+		},
+	)
+	nodeCount = promauto.NewGauge(
+		prometheus.GaugeOpts{
+			Name: "doublylinkedtree_node_count",
+			Help: "The number of nodes in the DAG array based store structure.",
+		},
+	)
+	headChangesCount = promauto.NewCounter(
+		prometheus.CounterOpts{
+			Name: "doublylinkedtree_head_changed_count",
+			Help: "The number of times head changes.",
+		},
+	)
+	calledHeadCount = promauto.NewCounter(
+		prometheus.CounterOpts{
+			Name: "doublylinkedtree_head_requested_count",
+			Help: "The number of times someone called head.",
+		},
+	)
+	processedBlockCount = promauto.NewCounter(
+		prometheus.CounterOpts{
+			Name: "doublylinkedtree_block_processed_count",
+			Help: "The number of times a block is processed for fork choice.",
+		},
+	)
+	processedAttestationCount = promauto.NewCounter(
+		prometheus.CounterOpts{
+			Name: "doublylinkedtree_attestation_processed_count",
+			Help: "The number of times an attestation is processed for fork choice.",
+		},
+	)
+	prunedCount = promauto.NewCounter(
+		prometheus.CounterOpts{
+			Name: "doublylinkedtree_pruned_count",
+			Help: "The number of times pruning happened.",
+		},
+	)
+	validatedCount = promauto.NewGauge(
+		prometheus.GaugeOpts{
+			Name: "doublylinkedtree_validated_count",
+			Help: "The number of blocks that have been fully validated.",
+		},
+	)
+)

beacon-chain/forkchoice/doubly-linked-tree/no_vote_test.go

@@ -0,0 +1,114 @@
+package doublylinkedtree
+
+import (
+	"context"
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/config/params"
+	"github.com/prysmaticlabs/prysm/testing/assert"
+	"github.com/prysmaticlabs/prysm/testing/require"
+)
+
+func TestNoVote_CanFindHead(t *testing.T) {
+	balances := make([]uint64, 16)
+	f := setup(1, 1)
+
+	// The head should always start at the finalized block.
+	r, err := f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	if r != params.BeaconConfig().ZeroHash {
+		t.Errorf("Incorrect head with genesis")
+	}
+
+	// Insert block 2 into the tree and verify head is at 2:
+	//         0
+	//        /
+	//       2 <- head
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(2), params.BeaconConfig().ZeroHash, 1, 1))
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(2), r, "Incorrect head for with justified epoch at 1")
+
+	// Insert block 1 into the tree and verify head is still at 2:
+	//            0
+	//           / \
+	//  head -> 2  1
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(2), r, "Incorrect head for with justified epoch at 1")
+
+	// Insert block 3 into the tree and verify head is still at 2:
+	//            0
+	//           / \
+	//  head -> 2  1
+	//             |
+	//             3
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(3), indexToHash(1), 1, 1))
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(2), r, "Incorrect head for with justified epoch at 1")
+
+	// Insert block 4 into the tree and verify head is at 4:
+	//            0
+	//           / \
+	//          2  1
+	//          |  |
+	//  head -> 4  3
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(4), indexToHash(2), 1, 1))
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(4), r, "Incorrect head for with justified epoch at 1")
+
+	// Insert block 5 with justified epoch of 2, verify head is still at 4.
+	//            0
+	//           / \
+	//          2  1
+	//          |  |
+	//  head -> 4  3
+	//          |
+	//          5 <- justified epoch = 2
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(5), indexToHash(4), 2, 1))
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(4), r, "Incorrect head for with justified epoch at 1")
+
+	// Verify there's an error when starting from a block with wrong justified epoch.
+	//            0
+	//           / \
+	//          2  1
+	//          |  |
+	//  head -> 4  3
+	//          |
+	//          5 <- starting from 5 with justified epoch 0 should error
+	_, err = f.Head(context.Background(), 1, indexToHash(5), balances, 1)
+	wanted := "head at slot 0 with weight 0 is not eligible, finalizedEpoch 1 != 1, justifiedEpoch 2 != 1"
+	require.ErrorContains(t, wanted, err)
+
+	// Set the justified epoch to 2 and start block to 5 to verify head is 5.
+	//            0
+	//           / \
+	//          2  1
+	//          |  |
+	//          4  3
+	//          |
+	//          5 <- head
+	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(5), r, "Incorrect head for with justified epoch at 2")
+
+	// Insert block 6 with justified epoch of 2, verify head is at 6.
+	//            0
+	//           / \
+	//          2  1
+	//          |  |
+	//          4  3
+	//          |
+	//          5
+	//          |
+	//          6 <- head
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(6), indexToHash(5), 2, 1))
+	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(6), r, "Incorrect head for with justified epoch at 2")
+}

beacon-chain/forkchoice/doubly-linked-tree/node.go

@@ -0,0 +1,153 @@
+package doublylinkedtree
+
+import (
+	"bytes"
+	"context"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/config/params"
+	pbrpc "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
+)
+
+// depth returns the length of the path to the root of Fork Choice
+func (n *Node) depth() uint64 {
+	ret := uint64(0)
+	for node := n.parent; node != nil; node = node.parent {
+		ret += 1
+	}
+	return ret
+}
+
+// applyWeightChanges recomputes the weight of the node passed as an argument and all of its descendants,
+// using the current balance stored in each node. This function requires a lock
+// in Store.nodesLock
+func (n *Node) applyWeightChanges(ctx context.Context) error {
+	// Recursively calling the children to sum their weights.
+	childrenWeight := uint64(0)
+	for _, child := range n.children {
+		if ctx.Err() != nil {
+			return ctx.Err()
+		}
+		if err := child.applyWeightChanges(ctx); err != nil {
+			return err
+		}
+		childrenWeight += child.weight
+	}
+	if n.root == params.BeaconConfig().ZeroHash {
+		return nil
+	}
+	n.weight = n.balance + childrenWeight
+	return nil
+}
+
+// updateBestDescendant updates the best descendant of this node and its children.
+func (n *Node) updateBestDescendant(ctx context.Context, justifiedEpoch, finalizedEpoch types.Epoch) error {
+	if ctx.Err() != nil {
+		return ctx.Err()
+	}
+	if len(n.children) == 0 {
+		n.bestDescendant = nil
+		return nil
+	}
+
+	var bestChild *Node
+	bestWeight := uint64(0)
+	hasViableDescendant := false
+	for _, child := range n.children {
+		if child == nil {
+			return ErrNilNode
+		}
+		if err := child.updateBestDescendant(ctx, justifiedEpoch, finalizedEpoch); err != nil {
+			return err
+		}
+		childLeadsToViableHead := child.leadsToViableHead(justifiedEpoch, finalizedEpoch)
+		if childLeadsToViableHead && !hasViableDescendant {
+			// The child leads to a viable head, but the current
+			// parent's best child doesn't.
+			bestWeight = child.weight
+			bestChild = child
+			hasViableDescendant = true
+		} else if childLeadsToViableHead {
+			// If both are viable, compare their weights.
+			if child.weight == bestWeight {
+				// Tie-breaker of equal weights by root.
+				if bytes.Compare(child.root[:], bestChild.root[:]) > 0 {
+					bestChild = child
+				}
+			} else if child.weight > bestWeight {
+				bestChild = child
+				bestWeight = child.weight
+			}
+		}
+	}
+	if hasViableDescendant {
+		if bestChild.bestDescendant == nil {
+			n.bestDescendant = bestChild
+		} else {
+			n.bestDescendant = bestChild.bestDescendant
+		}
+	} else {
+		n.bestDescendant = nil
+	}
+	return nil
+}
+
+// viableForHead returns true if the node is viable to head.
+// Any node with different finalized or justified epoch than
+// the ones in fork choice store should not be viable to head.
+func (n *Node) viableForHead(justifiedEpoch, finalizedEpoch types.Epoch) bool {
+	justified := justifiedEpoch == n.justifiedEpoch || justifiedEpoch == 0
+	finalized := finalizedEpoch == n.finalizedEpoch || finalizedEpoch == 0
+
+	return justified && finalized
+}
+
+func (n *Node) leadsToViableHead(justifiedEpoch, finalizedEpoch types.Epoch) bool {
+	if n.bestDescendant == nil {
+		return n.viableForHead(justifiedEpoch, finalizedEpoch)
+	}
+	return n.bestDescendant.viableForHead(justifiedEpoch, finalizedEpoch)
+}
+
+// setNodeAndParentValidated sets the current node and the parent as validated (i.e. non-optimistic).
+func (n *Node) setNodeAndParentValidated(ctx context.Context) error {
+	if ctx.Err() != nil {
+		return ctx.Err()
+	}
+
+	if !n.optimistic || n.parent == nil {
+		return nil
+	}
+
+	n.optimistic = false
+	validatedCount.Inc()
+	return n.parent.setNodeAndParentValidated(ctx)
+}
+
+// rpcNodes is used by the RPC Debug endpoint to return information
+// about all nodes in the fork choice store
+func (n *Node) rpcNodes(ret []*pbrpc.ForkChoiceNode) []*pbrpc.ForkChoiceNode {
+	for _, child := range n.children {
+		ret = child.rpcNodes(ret)
+	}
+	r := n.root
+	p := [32]byte{}
+	if n.parent != nil {
+		copy(p[:], n.parent.root[:])
+	}
+	b := [32]byte{}
+	if n.bestDescendant != nil {
+		copy(b[:], n.bestDescendant.root[:])
+	}
+	node := &pbrpc.ForkChoiceNode{
+		Slot:           n.slot,
+		Root:           r[:],
+		Parent:         p[:],
+		JustifiedEpoch: n.justifiedEpoch,
+		FinalizedEpoch: n.finalizedEpoch,
+		Weight:         n.weight,
+		BestDescendant: b[:],
+	}
+	ret = append(ret, node)
+	return ret
+}

beacon-chain/forkchoice/doubly-linked-tree/node_test.go

@@ -0,0 +1,206 @@
+package doublylinkedtree
+
+import (
+	"context"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/config/params"
+	"github.com/prysmaticlabs/prysm/testing/assert"
+	"github.com/prysmaticlabs/prysm/testing/require"
+)
+
+func TestNode_ApplyWeightChanges_PositiveChange(t *testing.T) {
+	f := setup(0, 0)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), indexToHash(1), 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 3, indexToHash(3), indexToHash(2), 0, 0))
+
+	// The updated balances of each node is 100
+	s := f.store
+
+	s.nodesLock.Lock()
+	defer s.nodesLock.Unlock()
+	s.nodeByRoot[indexToHash(1)].balance = 100
+	s.nodeByRoot[indexToHash(2)].balance = 100
+	s.nodeByRoot[indexToHash(3)].balance = 100
+
+	assert.NoError(t, s.treeRootNode.applyWeightChanges(ctx))
+
+	assert.Equal(t, uint64(300), s.nodeByRoot[indexToHash(1)].weight)
+	assert.Equal(t, uint64(200), s.nodeByRoot[indexToHash(2)].weight)
+	assert.Equal(t, uint64(100), s.nodeByRoot[indexToHash(3)].weight)
+}
+
+func TestNode_ApplyWeightChanges_NegativeChange(t *testing.T) {
+	f := setup(0, 0)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), indexToHash(1), 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 3, indexToHash(3), indexToHash(2), 0, 0))
+
+	// The updated balances of each node is 100
+	s := f.store
+	s.nodesLock.Lock()
+	defer s.nodesLock.Unlock()
+	s.nodeByRoot[indexToHash(1)].weight = 400
+	s.nodeByRoot[indexToHash(2)].weight = 400
+	s.nodeByRoot[indexToHash(3)].weight = 400
+
+	s.nodeByRoot[indexToHash(1)].balance = 100
+	s.nodeByRoot[indexToHash(2)].balance = 100
+	s.nodeByRoot[indexToHash(3)].balance = 100
+
+	assert.NoError(t, s.treeRootNode.applyWeightChanges(ctx))
+
+	assert.Equal(t, uint64(300), s.nodeByRoot[indexToHash(1)].weight)
+	assert.Equal(t, uint64(200), s.nodeByRoot[indexToHash(2)].weight)
+	assert.Equal(t, uint64(100), s.nodeByRoot[indexToHash(3)].weight)
+}
+
+func TestNode_UpdateBestDescendant_NonViableChild(t *testing.T) {
+	f := setup(1, 1)
+	ctx := context.Background()
+	// Input child is not viable.
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 2, 3))
+
+	// Verify parent's best child and best descendant are `none`.
+	s := f.store
+	assert.Equal(t, 1, len(s.treeRootNode.children))
+	nilBestDescendant := s.treeRootNode.bestDescendant == nil
+	assert.Equal(t, true, nilBestDescendant)
+}
+
+func TestNode_UpdateBestDescendant_ViableChild(t *testing.T) {
+	f := setup(1, 1)
+	ctx := context.Background()
+	// Input child is best descendant
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
+
+	s := f.store
+	assert.Equal(t, 1, len(s.treeRootNode.children))
+	assert.Equal(t, s.treeRootNode.children[0], s.treeRootNode.bestDescendant)
+}
+
+func TestNode_UpdateBestDescendant_HigherWeightChild(t *testing.T) {
+	f := setup(1, 1)
+	ctx := context.Background()
+	// Input child is best descendant
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), params.BeaconConfig().ZeroHash, 1, 1))
+
+	s := f.store
+	s.nodeByRoot[indexToHash(1)].weight = 100
+	s.nodeByRoot[indexToHash(2)].weight = 200
+	assert.NoError(t, s.treeRootNode.updateBestDescendant(ctx, 1, 1))
+
+	assert.Equal(t, 2, len(s.treeRootNode.children))
+	assert.Equal(t, s.treeRootNode.children[1], s.treeRootNode.bestDescendant)
+}
+
+func TestNode_UpdateBestDescendant_LowerWeightChild(t *testing.T) {
+	f := setup(1, 1)
+	ctx := context.Background()
+	// Input child is best descendant
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), params.BeaconConfig().ZeroHash, 1, 1))
+
+	s := f.store
+	s.nodeByRoot[indexToHash(1)].weight = 200
+	s.nodeByRoot[indexToHash(2)].weight = 100
+	assert.NoError(t, s.treeRootNode.updateBestDescendant(ctx, 1, 1))
+
+	assert.Equal(t, 2, len(s.treeRootNode.children))
+	assert.Equal(t, s.treeRootNode.children[0], s.treeRootNode.bestDescendant)
+}
+
+func TestNode_TestDepth(t *testing.T) {
+	f := setup(1, 1)
+	ctx := context.Background()
+	// Input child is best descendant
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), indexToHash(1), 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 3, indexToHash(3), params.BeaconConfig().ZeroHash, 1, 1))
+
+	s := f.store
+	require.Equal(t, s.nodeByRoot[indexToHash(2)].depth(), uint64(2))
+	require.Equal(t, s.nodeByRoot[indexToHash(3)].depth(), uint64(1))
+}
+
+func TestNode_ViableForHead(t *testing.T) {
+	tests := []struct {
+		n              *Node
+		justifiedEpoch types.Epoch
+		finalizedEpoch types.Epoch
+		want           bool
+	}{
+		{&Node{}, 0, 0, true},
+		{&Node{}, 1, 0, false},
+		{&Node{}, 0, 1, false},
+		{&Node{finalizedEpoch: 1, justifiedEpoch: 1}, 1, 1, true},
+		{&Node{finalizedEpoch: 1, justifiedEpoch: 1}, 2, 2, false},
+		{&Node{finalizedEpoch: 3, justifiedEpoch: 4}, 4, 3, true},
+	}
+	for _, tc := range tests {
+		got := tc.n.viableForHead(tc.justifiedEpoch, tc.finalizedEpoch)
+		assert.Equal(t, tc.want, got)
+	}
+}
+
+func TestNode_LeadsToViableHead(t *testing.T) {
+	f := setup(4, 3)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 3, indexToHash(3), indexToHash(1), 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 4, indexToHash(4), indexToHash(2), 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 5, indexToHash(5), indexToHash(3), 4, 3))
+
+	require.Equal(t, true, f.store.treeRootNode.leadsToViableHead(4, 3))
+	require.Equal(t, true, f.store.nodeByRoot[indexToHash(5)].leadsToViableHead(4, 3))
+	require.Equal(t, false, f.store.nodeByRoot[indexToHash(2)].leadsToViableHead(4, 3))
+	require.Equal(t, false, f.store.nodeByRoot[indexToHash(4)].leadsToViableHead(4, 3))
+}
+
+func TestNode_SetFullyValidated(t *testing.T) {
+	f := setup(1, 1)
+	ctx := context.Background()
+	// insert blocks in the fork pattern (optimistic status in parenthesis)
+	//
+	// 0 (false) -- 1 (false) -- 2 (false) -- 3 (true) -- 4 (true)
+	//               \
+	//                 -- 5 (true)
+	//
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.SetOptimisticToValid(ctx, params.BeaconConfig().ZeroHash))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), indexToHash(1), 1, 1))
+	require.NoError(t, f.SetOptimisticToValid(ctx, indexToHash(1)))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 3, indexToHash(3), indexToHash(2), 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 4, indexToHash(4), indexToHash(3), 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 5, indexToHash(5), indexToHash(1), 1, 1))
+
+	opt, err := f.IsOptimistic(ctx, indexToHash(5))
+	require.NoError(t, err)
+	require.Equal(t, true, opt)
+
+	opt, err = f.IsOptimistic(ctx, indexToHash(4))
+	require.NoError(t, err)
+	require.Equal(t, true, opt)
+
+	require.NoError(t, f.store.nodeByRoot[indexToHash(4)].setNodeAndParentValidated(ctx))
+
+	// block 5 should still be optimistic
+	opt, err = f.IsOptimistic(ctx, indexToHash(5))
+	require.NoError(t, err)
+	require.Equal(t, true, opt)
+
+	// block 4 and 3 should now be valid
+	opt, err = f.IsOptimistic(ctx, indexToHash(4))
+	require.NoError(t, err)
+	require.Equal(t, false, opt)
+
+	opt, err = f.IsOptimistic(ctx, indexToHash(3))
+	require.NoError(t, err)
+	require.Equal(t, false, opt)
+}

beacon-chain/forkchoice/doubly-linked-tree/optimistic_sync.go

@@ -0,0 +1,50 @@
+package doublylinkedtree
+
+import (
+	"context"
+)
+
+// removeNode removes the node with the given root and all of its children
+// from the Fork Choice Store.
+func (s *Store) removeNode(ctx context.Context, root [32]byte) error {
+	s.nodesLock.Lock()
+	defer s.nodesLock.Unlock()
+
+	node, ok := s.nodeByRoot[root]
+	if !ok || node == nil {
+		return ErrNilNode
+	}
+	if !node.optimistic || node.parent == nil {
+		return errInvalidOptimisticStatus
+	}
+	children := node.parent.children
+	if len(children) == 1 {
+		node.parent.children = []*Node{}
+	} else {
+		for i, n := range children {
+			if n == node {
+				if i != len(children)-1 {
+					children[i] = children[len(children)-1]
+				}
+				node.parent.children = children[:len(children)-2]
+				break
+			}
+		}
+	}
+	return s.removeNodeAndChildren(ctx, node)
+}
+
+// removeNodeAndChildren removes `node` and all of its descendant from the Store
+func (s *Store) removeNodeAndChildren(ctx context.Context, node *Node) error {
+	for _, child := range node.children {
+		if ctx.Err() != nil {
+			return ctx.Err()
+		}
+		if err := s.removeNodeAndChildren(ctx, child); err != nil {
+			return err
+		}
+	}
+
+	delete(s.nodeByRoot, node.root)
+	return nil
+}

beacon-chain/forkchoice/doubly-linked-tree/optimistic_sync_test.go

@@ -0,0 +1,70 @@
+package doublylinkedtree
+
+import (
+	"context"
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/config/params"
+	"github.com/prysmaticlabs/prysm/testing/require"
+)
+
+// We test the algorithm to update a node from SYNCING to INVALID
+// We start with the same diagram as above:
+//
+//                E -- F
+//               /
+//         C -- D
+//        /      \
+//  A -- B        G -- H -- I
+//        \        \
+//         J        -- K -- L
+//
+// And every block in the Fork choice is optimistic.
+//
+func TestPruneInvalid(t *testing.T) {
+	tests := []struct {
+		root             [32]byte // the root of the new INVALID block
+		wantedNodeNumber int
+	}{
+		{
+			[32]byte{'j'},
+			12,
+		},
+		{
+			[32]byte{'c'},
+			4,
+		},
+		{
+			[32]byte{'i'},
+			12,
+		},
+		{
+			[32]byte{'h'},
+			11,
+		},
+		{
+			[32]byte{'g'},
+			8,
+		},
+	}
+	for _, tc := range tests {
+		ctx := context.Background()
+		f := setup(1, 1)
+
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'j'}, [32]byte{'b'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 103, [32]byte{'d'}, [32]byte{'c'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 104, [32]byte{'e'}, [32]byte{'d'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 104, [32]byte{'g'}, [32]byte{'d'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'f'}, [32]byte{'e'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'h'}, [32]byte{'g'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'k'}, [32]byte{'g'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 106, [32]byte{'i'}, [32]byte{'h'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 106, [32]byte{'l'}, [32]byte{'k'}, 1, 1))
+
+		require.NoError(t, f.store.removeNode(context.Background(), tc.root))
+		require.Equal(t, tc.wantedNodeNumber, f.NodeCount())
+	}
+}

beacon-chain/forkchoice/doubly-linked-tree/proposer_boost.go

@@ -0,0 +1,73 @@
+package doublylinkedtree
+
+import (
+	"context"
+	"time"
+
+	"github.com/pkg/errors"
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/config/params"
+	"github.com/prysmaticlabs/prysm/time/slots"
+)
+
+// BoostProposerRoot sets the block root which should be boosted during
+// the LMD fork choice algorithm calculations. This is meant to reward timely,
+// proposed blocks which occur before a cutoff interval set to
+// SECONDS_PER_SLOT // INTERVALS_PER_SLOT.
+//
+//  time_into_slot = (store.time - store.genesis_time) % SECONDS_PER_SLOT
+//  is_before_attesting_interval = time_into_slot < SECONDS_PER_SLOT // INTERVALS_PER_SLOT
+//  if get_current_slot(store) == block.slot and is_before_attesting_interval:
+//      store.proposer_boost_root = hash_tree_root(block)
+func (f *ForkChoice) BoostProposerRoot(_ context.Context, blockSlot types.Slot, blockRoot [32]byte, genesisTime time.Time) error {
+	secondsPerSlot := params.BeaconConfig().SecondsPerSlot
+	timeIntoSlot := uint64(time.Since(genesisTime).Seconds()) % secondsPerSlot
+	isBeforeAttestingInterval := timeIntoSlot < secondsPerSlot/params.BeaconConfig().IntervalsPerSlot
+	currentSlot := slots.SinceGenesis(genesisTime)
+
+	// Only update the boosted proposer root to the incoming block root
+	// if the block is for the current, clock-based slot and the block was timely.
+	if currentSlot == blockSlot && isBeforeAttestingInterval {
+		f.store.proposerBoostLock.Lock()
+		f.store.proposerBoostRoot = blockRoot
+		f.store.proposerBoostLock.Unlock()
+	}
+	return nil
+}
+
+// ResetBoostedProposerRoot sets the value of the proposer boosted root to zeros.
+func (f *ForkChoice) ResetBoostedProposerRoot(_ context.Context) error {
+	f.store.proposerBoostLock.Lock()
+	f.store.proposerBoostRoot = [32]byte{}
+	f.store.proposerBoostLock.Unlock()
+	return nil
+}
+
+// Given a list of validator balances, we compute the proposer boost score
+// that should be given to a proposer based on their committee weight, derived from
+// the total active balances, the size of a committee, and a boost score constant.
+// IMPORTANT: The caller MUST pass in a list of validator balances where balances > 0 refer to active
+// validators while balances == 0 are for inactive validators.
+func computeProposerBoostScore(validatorBalances []uint64) (score uint64, err error) {
+	totalActiveBalance := uint64(0)
+	numActive := uint64(0)
+	for _, balance := range validatorBalances {
+		// We only consider balances > 0. The input slice should be constructed
+		// as balance > 0 for all active validators and 0 for inactive ones.
+		if balance == 0 {
+			continue
+		}
+		totalActiveBalance += balance
+		numActive += 1
+	}
+	if numActive == 0 {
+		// Should never happen.
+		err = errors.New("no active validators")
+		return
+	}
+	avgBalance := totalActiveBalance / numActive
+	committeeSize := numActive / uint64(params.BeaconConfig().SlotsPerEpoch)
+	committeeWeight := committeeSize * avgBalance
+	score = (committeeWeight * params.BeaconConfig().ProposerScoreBoost) / 100
+	return
+}

beacon-chain/forkchoice/doubly-linked-tree/proposer_boost_test.go

@@ -0,0 +1,480 @@
+package doublylinkedtree
+
+import (
+	"context"
+	"fmt"
+	"testing"
+	"time"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/config/params"
+	"github.com/prysmaticlabs/prysm/testing/assert"
+	"github.com/prysmaticlabs/prysm/testing/require"
+)
+
+// Simple, ex-ante attack mitigation using proposer boost.
+// In a nutshell, an adversarial block proposer in slot n+1 keeps its proposal hidden.
+// The honest block proposer in slot n+2 will then propose an honest block. The
+// adversary can now use its committee members’ votes from both slots n+1 and n+2.
+// and release their withheld block of slot n+2 in an attempt to win fork choice.
+// If the honest proposal is boosted at slot n+2, it will win against this attacker.
+func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
+	ctx := context.Background()
+	zeroHash := params.BeaconConfig().ZeroHash
+	balances := make([]uint64, 64) // 64 active validators.
+	for i := 0; i < len(balances); i++ {
+		balances[i] = 10
+	}
+	jEpoch, fEpoch := types.Epoch(0), types.Epoch(0)
+	t.Run("back-propagates boost score to ancestors after proposer boosting", func(t *testing.T) {
+		f := setup(jEpoch, fEpoch)
+
+		// The head should always start at the finalized block.
+		headRoot, err := f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, zeroHash, headRoot, "Incorrect head with genesis")
+
+		// Insert block at slot 1 into the tree and verify head is at that block:
+		//         0
+		//         |
+		//         1 <- HEAD
+		slot := types.Slot(1)
+		newRoot := indexToHash(1)
+		require.NoError(t,
+			f.InsertOptimisticBlock(
+				ctx,
+				slot,
+				newRoot,
+				headRoot,
+				jEpoch,
+				fEpoch,
+			),
+		)
+		f.ProcessAttestation(ctx, []uint64{0}, newRoot, fEpoch)
+		headRoot, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, newRoot, headRoot, "Incorrect head for justified epoch at slot 1")
+
+		// Insert block at slot 2 into the tree and verify head is at that block:
+		//         0
+		//         |
+		//         1
+		//         |
+		//         2 <- HEAD
+		slot = types.Slot(2)
+		newRoot = indexToHash(2)
+		require.NoError(t,
+			f.InsertOptimisticBlock(
+				ctx,
+				slot,
+				newRoot,
+				headRoot,
+				jEpoch,
+				fEpoch,
+			),
+		)
+		f.ProcessAttestation(ctx, []uint64{1}, newRoot, fEpoch)
+		headRoot, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, newRoot, headRoot, "Incorrect head for justified epoch at slot 2")
+
+		// Insert block at slot 3 into the tree and verify head is at that block:
+		//         0
+		//         |
+		//         1
+		//         |
+		//         2
+		//         |
+		//         3 <- HEAD
+		slot = types.Slot(3)
+		newRoot = indexToHash(3)
+		require.NoError(t,
+			f.InsertOptimisticBlock(
+				ctx,
+				slot,
+				newRoot,
+				headRoot,
+				jEpoch,
+				fEpoch,
+			),
+		)
+		f.ProcessAttestation(ctx, []uint64{2}, newRoot, fEpoch)
+		headRoot, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, newRoot, headRoot, "Incorrect head for justified epoch at slot 3")
+
+		// Insert a second block at slot 3 into the tree and boost its score.
+		//         0
+		//         |
+		//         1
+		//         |
+		//         2
+		//        / \
+		//       3   4 <- HEAD
+		slot = types.Slot(3)
+		newRoot = indexToHash(4)
+		require.NoError(t,
+			f.InsertOptimisticBlock(
+				ctx,
+				slot,
+				newRoot,
+				headRoot,
+				jEpoch,
+				fEpoch,
+			),
+		)
+		f.ProcessAttestation(ctx, []uint64{3}, newRoot, fEpoch)
+		threeSlots := 3 * params.BeaconConfig().SecondsPerSlot
+		genesisTime := time.Now().Add(-time.Second * time.Duration(threeSlots))
+		require.NoError(t, f.BoostProposerRoot(ctx, slot, newRoot, genesisTime))
+		headRoot, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, newRoot, headRoot, "Incorrect head for justified epoch at slot 3")
+
+		// Check the ancestor scores from the store.
+		require.Equal(t, 5, len(f.store.nodeByRoot))
+
+		// Expect nodes to have a boosted, back-propagated score.
+		// Ancestors have the added weights of their children. Genesis is a special exception at 0 weight,
+		require.Equal(t, f.store.treeRootNode.weight, uint64(0))
+
+		// Otherwise, assuming a block, A, that is not-genesis:
+		//
+		// A -> B -> C
+		//
+		//Where each one has a weight of 10 individually, the final weights will look like
+		//
+		// (A: 30) -> (B: 20) -> (C: 10)
+		//
+		// The boost adds 14 to the weight, so if C is boosted, we would have
+		//
+		// (A: 44) -> (B: 34) -> (C: 24)
+		//
+		// In this case, we have a small fork:
+		//
+		// (A: 54) -> (B: 44) -> (C: 34)
+		//                   \_->(D: 24)
+		//
+		// So B has its own weight, 10, and the sum of both C and D. That's why we see weight 54 in the
+		// middle instead of the normal progression of (44 -> 34 -> 24).
+		node1 := f.store.nodeByRoot[indexToHash(1)]
+		require.Equal(t, node1.weight, uint64(54))
+		node2 := f.store.nodeByRoot[indexToHash(2)]
+		require.Equal(t, node2.weight, uint64(44))
+		node3 := f.store.nodeByRoot[indexToHash(4)]
+		require.Equal(t, node3.weight, uint64(24))
+	})
+	t.Run("vanilla ex ante attack", func(t *testing.T) {
+		f := setup(jEpoch, fEpoch)
+
+		// The head should always start at the finalized block.
+		r, err := f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, zeroHash, r, "Incorrect head with genesis")
+
+		// Proposer from slot 1 does not reveal their block, B, at slot 1.
+		// Proposer at slot 2 does reveal their block, C, and it becomes the head.
+		// C builds on A, as proposer at slot 1 did not reveal B.
+		//         A
+		//        / \
+		//      (B?) \
+		//            \
+		//             C <- Slot 2 HEAD
+		honestBlockSlot := types.Slot(2)
+		honestBlock := indexToHash(2)
+		require.NoError(t,
+			f.InsertOptimisticBlock(
+				ctx,
+				honestBlockSlot,
+				honestBlock,
+				zeroHash,
+				jEpoch,
+				fEpoch,
+			),
+		)
+		r, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, honestBlock, r, "Incorrect head for justified epoch at slot 2")
+
+		maliciouslyWithheldBlockSlot := types.Slot(1)
+		maliciouslyWithheldBlock := indexToHash(1)
+		require.NoError(t,
+			f.InsertOptimisticBlock(
+				ctx,
+				maliciouslyWithheldBlockSlot,
+				maliciouslyWithheldBlock,
+				zeroHash,
+				jEpoch,
+				fEpoch,
+			),
+		)
+
+		// Ensure the head is C, the honest block.
+		r, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, honestBlock, r, "Incorrect head for justified epoch at slot 2")
+
+		// We boost the honest proposal at slot 2.
+		secondsPerSlot := time.Second * time.Duration(params.BeaconConfig().SecondsPerSlot)
+		genesis := time.Now().Add(-2 * secondsPerSlot)
+		require.NoError(t, f.BoostProposerRoot(ctx, honestBlockSlot, honestBlock, genesis))
+
+		// The maliciously withheld block has one vote.
+		votes := []uint64{1}
+		f.ProcessAttestation(ctx, votes, maliciouslyWithheldBlock, fEpoch)
+
+		// Ensure the head is STILL C, the honest block, as the honest block had proposer boost.
+		r, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, honestBlock, r, "Incorrect head for justified epoch at slot 2")
+	})
+	t.Run("adversarial attestations > proposer boosting", func(t *testing.T) {
+		f := setup(jEpoch, fEpoch)
+
+		// The head should always start at the finalized block.
+		r, err := f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, zeroHash, r, "Incorrect head with genesis")
+
+		// Proposer from slot 1 does not reveal their block, B, at slot 1.
+		// Proposer at slot 2 does reveal their block, C, and it becomes the head.
+		// C builds on A, as proposer at slot 1 did not reveal B.
+		//         A
+		//        / \
+		//	    (B?) \
+		//            \
+		//             C <- Slot 2 HEAD
+		honestBlockSlot := types.Slot(2)
+		honestBlock := indexToHash(2)
+		require.NoError(t,
+			f.InsertOptimisticBlock(
+				ctx,
+				honestBlockSlot,
+				honestBlock,
+				zeroHash,
+				jEpoch,
+				fEpoch,
+			),
+		)
+
+		// Ensure C is the head.
+		r, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, honestBlock, r, "Incorrect head for justified epoch at slot 2")
+
+		maliciouslyWithheldBlockSlot := types.Slot(1)
+		maliciouslyWithheldBlock := indexToHash(1)
+		require.NoError(t,
+			f.InsertOptimisticBlock(
+				ctx,
+				maliciouslyWithheldBlockSlot,
+				maliciouslyWithheldBlock,
+				zeroHash,
+				jEpoch,
+				fEpoch,
+			),
+		)
+
+		// Ensure C is still the head after the malicious proposer reveals their block.
+		r, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, honestBlock, r, "Incorrect head for justified epoch at slot 2")
+
+		// We boost the honest proposal at slot 2.
+		secondsPerSlot := time.Second * time.Duration(params.BeaconConfig().SecondsPerSlot)
+		genesis := time.Now().Add(-2 * secondsPerSlot)
+		require.NoError(t, f.BoostProposerRoot(ctx, honestBlockSlot, honestBlock, genesis))
+
+		// An attestation is received for B that has more voting power than C with the proposer boost,
+		// allowing B to then become the head if their attestation has enough adversarial votes.
+		votes := []uint64{1, 2}
+		f.ProcessAttestation(ctx, votes, maliciouslyWithheldBlock, fEpoch)
+
+		// Expect the head to have switched to B.
+		r, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, maliciouslyWithheldBlock, r, "Expected B to become the head")
+	})
+	t.Run("boosting necessary to sandwich attack", func(t *testing.T) {
+		// Boosting necessary to sandwich attack.
+		// Objects:
+		//	Block A - slot N
+		//	Block B (parent A) - slot N+1
+		//	Block C (parent A) - slot N+2
+		//	Block D (parent B) - slot N+3
+		//	Attestation_1 (Block C); size 1 - slot N+2 (honest)
+		// Steps:
+		//	Block A received at N — A is head
+		//	Block C received at N+2 — C is head
+		//	Block B received at N+2 — C is head
+		//	Attestation_1 received at N+3 — C is head
+		//	Block D received at N+3 — D is head
+		f := setup(jEpoch, fEpoch)
+		a := zeroHash
+
+		// The head should always start at the finalized block.
+		r, err := f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, zeroHash, r, "Incorrect head with genesis")
+
+		cSlot := types.Slot(2)
+		c := indexToHash(2)
+		require.NoError(t,
+			f.InsertOptimisticBlock(
+				ctx,
+				cSlot,
+				c,
+				a, // parent
+				jEpoch,
+				fEpoch,
+			),
+		)
+
+		// Ensure C is the head.
+		r, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, c, r, "Incorrect head for justified epoch at slot 2")
+
+		// We boost C.
+		secondsPerSlot := time.Second * time.Duration(params.BeaconConfig().SecondsPerSlot)
+		genesis := time.Now().Add(-2 * secondsPerSlot)
+		require.NoError(t, f.BoostProposerRoot(ctx, cSlot /* slot */, c, genesis))
+
+		bSlot := types.Slot(1)
+		b := indexToHash(1)
+		require.NoError(t,
+			f.InsertOptimisticBlock(
+				ctx,
+				bSlot,
+				b,
+				a, // parent
+				jEpoch,
+				fEpoch,
+			),
+		)
+
+		// Ensure C is still the head.
+		r, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, c, r, "Incorrect head for justified epoch at slot 2")
+
+		// An attestation for C is received at slot N+3.
+		votes := []uint64{1}
+		f.ProcessAttestation(ctx, votes, c, fEpoch)
+
+		// A block D, building on B, is received at slot N+3. It should not be able to win without boosting.
+		dSlot := types.Slot(3)
+		d := indexToHash(3)
+		require.NoError(t,
+			f.InsertOptimisticBlock(
+				ctx,
+				dSlot,
+				d,
+				b, // parent
+				jEpoch,
+				fEpoch,
+			),
+		)
+
+		// D cannot win without a boost.
+		r, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, c, r, "Expected C to remain the head")
+
+		// Block D receives the boost.
+		genesis = time.Now().Add(-3 * secondsPerSlot)
+		require.NoError(t, f.BoostProposerRoot(ctx, dSlot /* slot */, d, genesis))
+
+		// Ensure D becomes the head thanks to boosting.
+		r, err = f.Head(ctx, jEpoch, zeroHash, balances, fEpoch)
+		require.NoError(t, err)
+		assert.Equal(t, d, r, "Expected D to become the head")
+	})
+}
+
+func TestForkChoice_BoostProposerRoot(t *testing.T) {
+	params.SetupTestConfigCleanup(t)
+	cfg := params.BeaconConfig()
+	cfg.SecondsPerSlot = 6
+	cfg.IntervalsPerSlot = 3
+	params.OverrideBeaconConfig(cfg)
+	ctx := context.Background()
+
+	t.Run("does not boost block from different slot", func(t *testing.T) {
+		f := &ForkChoice{
+			store: &Store{},
+		}
+		// Genesis set to 1 slot ago.
+		genesis := time.Now().Add(-time.Duration(cfg.SecondsPerSlot) * time.Second)
+		blockRoot := [32]byte{'A'}
+
+		// Trying to boost a block from slot 0 should not work.
+		err := f.BoostProposerRoot(ctx, types.Slot(0), blockRoot, genesis)
+		require.NoError(t, err)
+		require.DeepEqual(t, [32]byte{}, f.store.proposerBoostRoot)
+	})
+	t.Run("does not boost untimely block from same slot", func(t *testing.T) {
+		f := &ForkChoice{
+			store: &Store{},
+		}
+		// Genesis set to 1 slot ago + X where X > attesting interval.
+		genesis := time.Now().Add(-time.Duration(cfg.SecondsPerSlot) * time.Second)
+		attestingInterval := time.Duration(cfg.SecondsPerSlot / cfg.IntervalsPerSlot)
+		greaterThanAttestingInterval := attestingInterval + 100*time.Millisecond
+		genesis = genesis.Add(-greaterThanAttestingInterval * time.Second)
+		blockRoot := [32]byte{'A'}
+
+		// Trying to boost a block from slot 1 that is untimely should not work.
+		err := f.BoostProposerRoot(ctx, types.Slot(1), blockRoot, genesis)
+		require.NoError(t, err)
+		require.DeepEqual(t, [32]byte{}, f.store.proposerBoostRoot)
+	})
+	t.Run("boosts perfectly timely block from same slot", func(t *testing.T) {
+		f := &ForkChoice{
+			store: &Store{},
+		}
+		// Genesis set to 1 slot ago + 0 seconds into the attesting interval.
+		genesis := time.Now().Add(-time.Duration(cfg.SecondsPerSlot) * time.Second)
+		fmt.Println(genesis)
+		blockRoot := [32]byte{'A'}
+
+		err := f.BoostProposerRoot(ctx, types.Slot(1), blockRoot, genesis)
+		require.NoError(t, err)
+		require.DeepEqual(t, [32]byte{'A'}, f.store.proposerBoostRoot)
+	})
+	t.Run("boosts timely block from same slot", func(t *testing.T) {
+		f := &ForkChoice{
+			store: &Store{},
+		}
+		// Genesis set to 1 slot ago + (attesting interval / 2).
+		genesis := time.Now().Add(-time.Duration(cfg.SecondsPerSlot) * time.Second)
+		blockRoot := [32]byte{'A'}
+		halfAttestingInterval := time.Second
+		genesis = genesis.Add(-halfAttestingInterval)
+
+		err := f.BoostProposerRoot(ctx, types.Slot(1), blockRoot, genesis)
+		require.NoError(t, err)
+		require.DeepEqual(t, [32]byte{'A'}, f.store.proposerBoostRoot)
+	})
+}
+
+func TestForkChoice_computeProposerBoostScore(t *testing.T) {
+	t.Run("nil justified balances throws error", func(t *testing.T) {
+		_, err := computeProposerBoostScore(nil)
+		require.ErrorContains(t, "no active validators", err)
+	})
+	t.Run("normal active balances computes score", func(t *testing.T) {
+		validatorBalances := make([]uint64, 64) // Num validators
+		for i := 0; i < len(validatorBalances); i++ {
+			validatorBalances[i] = 10
+		}
+		// Avg balance is 10, and the number of validators is 64.
+		// With a committee size of num validators (64) / slots per epoch (32) == 2.
+		// we then have a committee weight of avg balance * committee size = 10 * 2 = 20.
+		// The score then becomes 10 * PROPOSER_SCORE_BOOST // 100, which is
+		// 20 * 70 / 100 = 14.
+		score, err := computeProposerBoostScore(validatorBalances)
+		require.NoError(t, err)
+		require.Equal(t, uint64(14), score)
+	})
+}

beacon-chain/forkchoice/doubly-linked-tree/store.go

@@ -0,0 +1,215 @@
+package doublylinkedtree
+
+import (
+	"context"
+	"fmt"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
+	"github.com/prysmaticlabs/prysm/config/params"
+	"go.opencensus.io/trace"
+)
+
+// This defines the minimal number of block nodes that can be in the tree
+// before getting pruned upon new finalization.
+const defaultPruneThreshold = 256
+
+// applyProposerBoostScore applies the current proposer boost scores to the
+// relevant nodes
+func (s *Store) applyProposerBoostScore(newBalances []uint64) error {
+	s.proposerBoostLock.Lock()
+	defer s.proposerBoostLock.Unlock()
+
+	proposerScore := uint64(0)
+	var err error
+	if s.previousProposerBoostRoot != params.BeaconConfig().ZeroHash {
+		previousNode, ok := s.nodeByRoot[s.previousProposerBoostRoot]
+		if !ok || previousNode == nil {
+			return errInvalidProposerBoostRoot
+		}
+		previousNode.balance -= s.previousProposerBoostScore
+	}
+
+	if s.proposerBoostRoot != params.BeaconConfig().ZeroHash {
+		currentNode, ok := s.nodeByRoot[s.proposerBoostRoot]
+		if !ok || currentNode == nil {
+			return errInvalidProposerBoostRoot
+		}
+		proposerScore, err = computeProposerBoostScore(newBalances)
+		if err != nil {
+			return err
+		}
+		currentNode.balance += proposerScore
+	}
+	s.previousProposerBoostRoot = s.proposerBoostRoot
+	s.previousProposerBoostScore = proposerScore
+	return nil
+}
+
+// ProposerBoost of fork choice store.
+func (s *Store) proposerBoost() [fieldparams.RootLength]byte {
+	s.proposerBoostLock.RLock()
+	defer s.proposerBoostLock.RUnlock()
+	return s.proposerBoostRoot
+}
+
+// PruneThreshold of fork choice store.
+func (s *Store) PruneThreshold() uint64 {
+	return s.pruneThreshold
+}
+
+// head starts from justified root and then follows the best descendant links
+// to find the best block for head. This function assumes a lock on s.nodesLock
+func (s *Store) head(ctx context.Context, justifiedRoot [32]byte) ([32]byte, error) {
+	_, span := trace.StartSpan(ctx, "doublyLinkedForkchoice.head")
+	defer span.End()
+
+	// JustifiedRoot has to be known
+	justifiedNode, ok := s.nodeByRoot[justifiedRoot]
+	if !ok || justifiedNode == nil {
+		return [32]byte{}, errUnknownJustifiedRoot
+	}
+
+	// If the justified node doesn't have a best descendant,
+	// the best node is itself.
+	bestDescendant := justifiedNode.bestDescendant
+	if bestDescendant == nil {
+		bestDescendant = justifiedNode
+	}
+
+	if !bestDescendant.viableForHead(s.justifiedEpoch, s.finalizedEpoch) {
+		return [32]byte{}, fmt.Errorf("head at slot %d with weight %d is not eligible, finalizedEpoch %d != %d, justifiedEpoch %d != %d",
+			bestDescendant.slot, bestDescendant.weight/10e9, bestDescendant.finalizedEpoch, s.finalizedEpoch, bestDescendant.justifiedEpoch, s.justifiedEpoch)
+	}
+
+	// Update metrics.
+	if bestDescendant != s.headNode {
+		headChangesCount.Inc()
+		headSlotNumber.Set(float64(bestDescendant.slot))
+		s.headNode = bestDescendant
+	}
+
+	return bestDescendant.root, nil
+}
+
+// insert registers a new block node to the fork choice store's node list.
+// It then updates the new node's parent with best child and descendant node.
+func (s *Store) insert(ctx context.Context,
+	slot types.Slot,
+	root, parentRoot [fieldparams.RootLength]byte,
+	justifiedEpoch, finalizedEpoch types.Epoch) error {
+	_, span := trace.StartSpan(ctx, "doublyLinkedForkchoice.insert")
+	defer span.End()
+
+	s.nodesLock.Lock()
+	defer s.nodesLock.Unlock()
+
+	// Return if the block has been inserted into Store before.
+	if _, ok := s.nodeByRoot[root]; ok {
+		return nil
+	}
+
+	parent := s.nodeByRoot[parentRoot]
+
+	n := &Node{
+		slot:           slot,
+		root:           root,
+		parent:         parent,
+		justifiedEpoch: justifiedEpoch,
+		finalizedEpoch: finalizedEpoch,
+		optimistic:     true,
+	}
+
+	s.nodeByRoot[root] = n
+	if parent != nil {
+		parent.children = append(parent.children, n)
+		if err := s.treeRootNode.updateBestDescendant(ctx, s.justifiedEpoch, s.finalizedEpoch); err != nil {
+			return err
+		}
+	}
+
+	// Set the node as root if the store was empty
+	if s.treeRootNode == nil {
+		s.treeRootNode = n
+		s.headNode = n
+	}
+
+	// Update metrics.
+	processedBlockCount.Inc()
+	nodeCount.Set(float64(len(s.nodeByRoot)))
+
+	return nil
+}
+
+// updateCheckpoints Update the justified / finalized epochs in store if necessary.
+func (s *Store) updateCheckpoints(justifiedEpoch, finalizedEpoch types.Epoch) {
+	s.justifiedEpoch = justifiedEpoch
+	s.finalizedEpoch = finalizedEpoch
+}
+
+// pruneFinalizedNodeByRootMap prunes the `nodeByRoot` map
+// starting from `node` down to the finalized Node or to a leaf of the Fork
+// choice store. This method assumes a lock on nodesLock.
+func (s *Store) pruneFinalizedNodeByRootMap(ctx context.Context, node, finalizedNode *Node) error {
+	if ctx.Err() != nil {
+		return ctx.Err()
+	}
+	if node == finalizedNode {
+		return nil
+	}
+	for _, child := range node.children {
+		if err := s.pruneFinalizedNodeByRootMap(ctx, child, finalizedNode); err != nil {
+			return err
+		}
+	}
+
+	delete(s.nodeByRoot, node.root)
+	return nil
+}
+
+// prune prunes the fork choice store with the new finalized root. The store is only pruned if the input
+// root is different than the current store finalized root, and the number of the store has met prune threshold.
+// This function does not prune for invalid optimistically synced nodes, it deals only with pruning upon finalization
+func (s *Store) prune(ctx context.Context, finalizedRoot [32]byte) error {
+	_, span := trace.StartSpan(ctx, "doublyLinkedForkchoice.Prune")
+	defer span.End()
+
+	s.nodesLock.Lock()
+	defer s.nodesLock.Unlock()
+
+	finalizedNode, ok := s.nodeByRoot[finalizedRoot]
+	if !ok || finalizedNode == nil {
+		return errUnknownFinalizedRoot
+	}
+
+	// The number of the nodes has not met the prune threshold.
+	// Pruning at small numbers incurs more cost than benefit.
+	if finalizedNode.depth() < s.pruneThreshold {
+		return nil
+	}
+
+	// Prune nodeByRoot starting from root
+	if err := s.pruneFinalizedNodeByRootMap(ctx, s.treeRootNode, finalizedNode); err != nil {
+		return err
+	}
+
+	finalizedNode.parent = nil
+	s.treeRootNode = finalizedNode
+
+	prunedCount.Inc()
+	return nil
+}
+
+// tips returns a list of possible heads from fork choice store, it returns the
+// roots and the slots of the leaf nodes.
+func (s *Store) tips() ([][32]byte, []types.Slot) {
+	var roots [][32]byte
+	var slots []types.Slot
+	for root, node := range s.nodeByRoot {
+		if len(node.children) == 0 {
+			roots = append(roots, root)
+			slots = append(slots, node.slot)
+		}
+	}
+	return roots, slots
+}

beacon-chain/forkchoice/doubly-linked-tree/store_test.go

@@ -0,0 +1,274 @@
+package doublylinkedtree
+
+import (
+	"context"
+	"testing"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	"github.com/prysmaticlabs/prysm/config/params"
+	"github.com/prysmaticlabs/prysm/testing/assert"
+	"github.com/prysmaticlabs/prysm/testing/require"
+)
+
+func TestStore_PruneThreshold(t *testing.T) {
+	s := &Store{
+		pruneThreshold: defaultPruneThreshold,
+	}
+	if got := s.PruneThreshold(); got != defaultPruneThreshold {
+		t.Errorf("PruneThreshold() = %v, want %v", got, defaultPruneThreshold)
+	}
+}
+
+func TestStore_JustifiedEpoch(t *testing.T) {
+	j := types.Epoch(100)
+	f := setup(j, j)
+	require.Equal(t, j, f.JustifiedEpoch())
+}
+
+func TestStore_FinalizedEpoch(t *testing.T) {
+	j := types.Epoch(50)
+	f := setup(j, j)
+	require.Equal(t, j, f.FinalizedEpoch())
+}
+
+func TestStore_NodeCount(t *testing.T) {
+	f := setup(0, 0)
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.Equal(t, 2, f.NodeCount())
+}
+
+func TestStore_NodeByRoot(t *testing.T) {
+	f := setup(0, 0)
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 2, indexToHash(2), indexToHash(1), 0, 0))
+	node0 := f.store.treeRootNode
+	node1 := node0.children[0]
+	node2 := node1.children[0]
+
+	expectedRoots := map[[32]byte]*Node{
+		params.BeaconConfig().ZeroHash: node0,
+		indexToHash(1):                 node1,
+		indexToHash(2):                 node2,
+	}
+
+	require.Equal(t, 3, f.NodeCount())
+	for root, node := range f.store.nodeByRoot {
+		v, ok := expectedRoots[root]
+		require.Equal(t, ok, true)
+		require.Equal(t, v, node)
+	}
+}
+
+func TestForkChoice_HasNode(t *testing.T) {
+	f := setup(0, 0)
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.Equal(t, true, f.HasNode(indexToHash(1)))
+}
+
+func TestStore_Head_UnknownJustifiedRoot(t *testing.T) {
+	f := setup(0, 0)
+
+	_, err := f.store.head(context.Background(), [32]byte{'a'})
+	assert.ErrorContains(t, errUnknownJustifiedRoot.Error(), err)
+}
+
+func TestStore_Head_Itself(t *testing.T) {
+	f := setup(0, 0)
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+
+	// Since the justified node does not have a best descendant so the best node
+	// is itself.
+	h, err := f.store.head(context.Background(), indexToHash(1))
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(1), h)
+}
+
+func TestStore_Head_BestDescendant(t *testing.T) {
+	f := setup(0, 0)
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 2, indexToHash(2), indexToHash(1), 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 3, indexToHash(3), indexToHash(1), 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 4, indexToHash(4), indexToHash(2), 0, 0))
+	h, err := f.store.head(context.Background(), indexToHash(1))
+	require.NoError(t, err)
+	require.Equal(t, h, indexToHash(4))
+}
+
+func TestStore_UpdateBestDescendant_ContextCancelled(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	f := setup(0, 0)
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	cancel()
+	err := f.InsertOptimisticBlock(ctx, 2, indexToHash(2), indexToHash(1), 0, 0)
+	require.ErrorContains(t, "context canceled", err)
+}
+
+func TestStore_Insert(t *testing.T) {
+	// The new node does not have a parent.
+	treeRootNode := &Node{slot: 0, root: indexToHash(0)}
+	nodeByRoot := map[[32]byte]*Node{indexToHash(0): treeRootNode}
+	s := &Store{nodeByRoot: nodeByRoot, treeRootNode: treeRootNode}
+	require.NoError(t, s.insert(context.Background(), 100, indexToHash(100), indexToHash(0), 1, 1))
+	assert.Equal(t, 2, len(s.nodeByRoot), "Did not insert block")
+	assert.Equal(t, (*Node)(nil), treeRootNode.parent, "Incorrect parent")
+	assert.Equal(t, 1, len(treeRootNode.children), "Incorrect children number")
+	child := treeRootNode.children[0]
+	assert.Equal(t, types.Epoch(1), child.justifiedEpoch, "Incorrect justification")
+	assert.Equal(t, types.Epoch(1), child.finalizedEpoch, "Incorrect finalization")
+	assert.Equal(t, indexToHash(100), child.root, "Incorrect root")
+}
+
+func TestStore_updateCheckpoints(t *testing.T) {
+	f := setup(0, 0)
+	s := f.store
+
+	s.updateCheckpoints(1, 1)
+	assert.Equal(t, types.Epoch(1), s.justifiedEpoch, "Did not update justified epoch")
+	assert.Equal(t, types.Epoch(1), s.finalizedEpoch, "Did not update finalized epoch")
+}
+
+func TestStore_Prune_LessThanThreshold(t *testing.T) {
+	// Define 100 nodes in store.
+	numOfNodes := uint64(100)
+	f := setup(0, 0)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	for i := uint64(2); i < numOfNodes; i++ {
+		require.NoError(t, f.InsertOptimisticBlock(ctx, types.Slot(i), indexToHash(i), indexToHash(i-1), 0, 0))
+	}
+
+	s := f.store
+	s.pruneThreshold = 100
+
+	// Finalized root has depth 99 so everything before it should be pruned,
+	// but PruneThreshold is at 100 so nothing will be pruned.
+	require.NoError(t, s.prune(context.Background(), indexToHash(99)))
+	assert.Equal(t, 100, len(s.nodeByRoot), "Incorrect nodes count")
+}
+
+func TestStore_Prune_MoreThanThreshold(t *testing.T) {
+	// Define 100 nodes in store.
+	numOfNodes := uint64(100)
+	f := setup(0, 0)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	for i := uint64(2); i < numOfNodes; i++ {
+		require.NoError(t, f.InsertOptimisticBlock(ctx, types.Slot(i), indexToHash(i), indexToHash(i-1), 0, 0))
+	}
+
+	s := f.store
+	s.pruneThreshold = 0
+
+	// Finalized root is at index 99 so everything before 99 should be pruned.
+	require.NoError(t, s.prune(context.Background(), indexToHash(99)))
+	assert.Equal(t, 1, len(s.nodeByRoot), "Incorrect nodes count")
+}
+
+func TestStore_Prune_MoreThanOnce(t *testing.T) {
+	// Define 100 nodes in store.
+	numOfNodes := uint64(100)
+	f := setup(0, 0)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	for i := uint64(2); i < numOfNodes; i++ {
+		require.NoError(t, f.InsertOptimisticBlock(ctx, types.Slot(i), indexToHash(i), indexToHash(i-1), 0, 0))
+	}
+
+	s := f.store
+	s.pruneThreshold = 0
+
+	// Finalized root is at index 11 so everything before 11 should be pruned.
+	require.NoError(t, s.prune(context.Background(), indexToHash(10)))
+	assert.Equal(t, 90, len(s.nodeByRoot), "Incorrect nodes count")
+
+	// One more time.
+	require.NoError(t, s.prune(context.Background(), indexToHash(20)))
+	assert.Equal(t, 80, len(s.nodeByRoot), "Incorrect nodes count")
+}
+
+// This unit tests starts with a simple branch like this
+//
+//       - 1
+//     /
+// -- 0 -- 2
+//
+// And we finalize 1. As a result only 1 should survive
+func TestStore_Prune_NoDanglingBranch(t *testing.T) {
+	f := setup(0, 0)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), params.BeaconConfig().ZeroHash, 0, 0))
+	f.store.pruneThreshold = 0
+
+	s := f.store
+	require.NoError(t, s.prune(context.Background(), indexToHash(1)))
+	require.Equal(t, len(s.nodeByRoot), 1)
+}
+
+// This test starts with the following branching diagram
+/// We start with the following diagram
+//
+//                E -- F
+//               /
+//         C -- D
+//        /      \
+//  A -- B        G -- H -- I
+//        \        \
+//         J        -- K -- L
+//
+//
+func TestStore_tips(t *testing.T) {
+	ctx := context.Background()
+	f := setup(1, 1)
+
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'j'}, [32]byte{'b'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 103, [32]byte{'d'}, [32]byte{'c'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 104, [32]byte{'e'}, [32]byte{'d'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 104, [32]byte{'g'}, [32]byte{'d'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'f'}, [32]byte{'e'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'h'}, [32]byte{'g'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'k'}, [32]byte{'g'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 106, [32]byte{'i'}, [32]byte{'h'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 106, [32]byte{'l'}, [32]byte{'k'}, 1, 1))
+	expectedMap := map[[32]byte]types.Slot{
+		[32]byte{'f'}: 105,
+		[32]byte{'i'}: 106,
+		[32]byte{'l'}: 106,
+		[32]byte{'j'}: 102,
+	}
+	roots, slots := f.store.tips()
+	for i, r := range roots {
+		expectedSlot, ok := expectedMap[r]
+		require.Equal(t, true, ok)
+		require.Equal(t, slots[i], expectedSlot)
+	}
+}
+
+func TestStore_PruneMapsNodes(t *testing.T) {
+	f := setup(0, 0)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), params.BeaconConfig().ZeroHash, 0, 0))
+
+	s := f.store
+	s.pruneThreshold = 0
+	require.NoError(t, s.prune(context.Background(), indexToHash(uint64(1))))
+	require.Equal(t, len(s.nodeByRoot), 1)
+
+}
+
+func TestStore_HasParent(t *testing.T) {
+	f := setup(1, 1)
+	ctx := context.Background()
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 1, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 2, indexToHash(2), indexToHash(1), 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 3, indexToHash(3), indexToHash(2), 1, 1))
+	require.Equal(t, false, f.HasParent(params.BeaconConfig().ZeroHash))
+	require.Equal(t, true, f.HasParent(indexToHash(1)))
+	require.Equal(t, true, f.HasParent(indexToHash(2)))
+	require.Equal(t, true, f.HasParent(indexToHash(3)))
+	require.Equal(t, false, f.HasParent(indexToHash(4)))
+}

beacon-chain/forkchoice/doubly-linked-tree/types.go

@@ -0,0 +1,53 @@
+package doublylinkedtree
+
+import (
+	"sync"
+
+	types "github.com/prysmaticlabs/eth2-types"
+	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
+)
+
+// ForkChoice defines the overall fork choice store which includes all block nodes, validator's latest votes and balances.
+type ForkChoice struct {
+	store     *Store
+	votes     []Vote // tracks individual validator's last vote.
+	votesLock sync.RWMutex
+	balances  []uint64 // tracks individual validator's last justified balances.
+}
+
+// Store defines the fork choice store which includes block nodes and the last view of checkpoint information.
+type Store struct {
+	justifiedEpoch             types.Epoch                            // latest justified epoch in store.
+	finalizedEpoch             types.Epoch                            // latest finalized epoch in store.
+	pruneThreshold             uint64                                 // do not prune tree unless threshold is reached.
+	proposerBoostRoot          [fieldparams.RootLength]byte           // latest block root that was boosted after being received in a timely manner.
+	previousProposerBoostRoot  [fieldparams.RootLength]byte           // previous block root that was boosted after being received in a timely manner.
+	previousProposerBoostScore uint64                                 // previous proposer boosted root score.
+	treeRootNode               *Node                                  // the root node of the store tree.
+	headNode                   *Node                                  // last head Node
+	nodeByRoot                 map[[fieldparams.RootLength]byte]*Node // nodes indexed by roots.
+	nodesLock                  sync.RWMutex
+	proposerBoostLock          sync.RWMutex
+}
+
+// Node defines the individual block which includes its block parent, ancestor and how much weight accounted for it.
+// This is used as an array based stateful DAG for efficient fork choice look up.
+type Node struct {
+	slot           types.Slot                   // slot of the block converted to the node.
+	root           [fieldparams.RootLength]byte // root of the block converted to the node.
+	parent         *Node                        // parent index of this node.
+	children       []*Node                      // the list of direct children of this Node
+	justifiedEpoch types.Epoch                  // justifiedEpoch of this node.
+	finalizedEpoch types.Epoch                  // finalizedEpoch of this node.
+	balance        uint64                       // the balance that voted for this node directly
+	weight         uint64                       // weight of this node: the total balance including children
+	bestDescendant *Node                        // bestDescendant node of this node.
+	optimistic     bool                         // whether the block has been fully validated or not
+}
+
+// Vote defines an individual validator's vote.
+type Vote struct {
+	currentRoot [fieldparams.RootLength]byte // current voting root.
+	nextRoot    [fieldparams.RootLength]byte // next voting root.
+	nextEpoch   types.Epoch                  // epoch of next voting period.
+}

beacon-chain/forkchoice/doubly-linked-tree/vote_test.go

@@ -0,0 +1,297 @@
+package doublylinkedtree
+
+import (
+	"context"
+	"testing"
+
+	"github.com/prysmaticlabs/prysm/config/params"
+	"github.com/prysmaticlabs/prysm/testing/assert"
+	"github.com/prysmaticlabs/prysm/testing/require"
+)
+
+func TestVotes_CanFindHead(t *testing.T) {
+	balances := []uint64{1, 1}
+	f := setup(1, 1)
+
+	// The head should always start at the finalized block.
+	r, err := f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, params.BeaconConfig().ZeroHash, r, "Incorrect head with genesis")
+
+	// Insert block 2 into the tree and verify head is at 2:
+	//         0
+	//        /
+	//       2 <- head
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(2), params.BeaconConfig().ZeroHash, 1, 1))
+
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(2), r, "Incorrect head for with justified epoch at 1")
+
+	// Insert block 1 into the tree and verify head is still at 2:
+	//            0
+	//           / \
+	//  head -> 2  1
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
+
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(2), r, "Incorrect head for with justified epoch at 1")
+
+	// Add a vote to block 1 of the tree and verify head is switched to 1:
+	//            0
+	//           / \
+	//          2  1 <- +vote, new head
+	f.ProcessAttestation(context.Background(), []uint64{0}, indexToHash(1), 2)
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(1), r, "Incorrect head for with justified epoch at 1")
+
+	// Add a vote to block 2 of the tree and verify head is switched to 2:
+	//                     0
+	//                    / \
+	// vote, new head -> 2  1
+	f.ProcessAttestation(context.Background(), []uint64{1}, indexToHash(2), 2)
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(2), r, "Incorrect head for with justified epoch at 1")
+
+	// Insert block 3 into the tree and verify head is still at 2:
+	//            0
+	//           / \
+	//  head -> 2  1
+	//             |
+	//             3
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(3), indexToHash(1), 1, 1))
+
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(2), r, "Incorrect head for with justified epoch at 1")
+
+	// Move validator 0's vote from 1 to 3 and verify head is still at 2:
+	//            0
+	//           / \
+	//  head -> 2  1 <- old vote
+	//             |
+	//             3 <- new vote
+	f.ProcessAttestation(context.Background(), []uint64{0}, indexToHash(3), 3)
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(2), r, "Incorrect head for with justified epoch at 1")
+
+	// Move validator 1's vote from 2 to 1 and verify head is switched to 3:
+	//               0
+	//              / \
+	// old vote -> 2  1 <- new vote
+	//                |
+	//                3 <- head
+	f.ProcessAttestation(context.Background(), []uint64{1}, indexToHash(1), 3)
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(3), r, "Incorrect head for with justified epoch at 1")
+
+	// Insert block 4 into the tree and verify head is at 4:
+	//            0
+	//           / \
+	//          2  1
+	//             |
+	//             3
+	//             |
+	//             4 <- head
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(4), indexToHash(3), 1, 1))
+
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(4), r, "Incorrect head for with justified epoch at 1")
+
+	// Insert block 5 with justified epoch 2, it should be filtered out:
+	//            0
+	//           / \
+	//          2  1
+	//             |
+	//             3
+	//             |
+	//             4 <- head
+	//            /
+	//           5 <- justified epoch = 2
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(5), indexToHash(4), 2, 2))
+
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(4), r, "Incorrect head for with justified epoch at 1")
+
+	// Insert block 6 with justified epoch 0:
+	//            0
+	//           / \
+	//          2  1
+	//             |
+	//             3
+	//             |
+	//             4 <- head
+	//            / \
+	//           5  6 <- justified epoch = 0
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(6), indexToHash(4), 1, 1))
+
+	// Moved 2 votes to block 5:
+	//            0
+	//           / \
+	//          2  1
+	//             |
+	//             3
+	//             |
+	//             4
+	//            / \
+	// 2 votes-> 5  6
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(6), indexToHash(4), 1, 1))
+
+	f.ProcessAttestation(context.Background(), []uint64{0, 1}, indexToHash(5), 4)
+
+	// Inset blocks 7, 8 and 9:
+	// 6 should still be the head, even though 5 has all the votes.
+	//            0
+	//           / \
+	//          2  1
+	//             |
+	//             3
+	//             |
+	//             4
+	//            / \
+	//           5  6 <- head
+	//           |
+	//           7
+	//           |
+	//           8
+	//           |
+	//           9
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(7), indexToHash(5), 2, 2))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(8), indexToHash(7), 2, 2))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(9), indexToHash(8), 2, 2))
+
+	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(6), r, "Incorrect head for with justified epoch at 1")
+
+	// Update fork choice justified epoch to 1 and start block to 5.
+	// Verify 9 is the head:
+	//            0
+	//           / \
+	//          2  1
+	//             |
+	//             3
+	//             |
+	//             4
+	//            / \
+	//           5  6
+	//           |
+	//           7
+	//           |
+	//           8
+	//           |
+	//           9 <- head
+	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 2)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(9), r, "Incorrect head for with justified epoch at 2")
+
+	// Insert block 10 and 2 validators updated their vote to 9.
+	// Verify 9 is the head:
+	//             0
+	//            / \
+	//           2  1
+	//              |
+	//              3
+	//              |
+	//              4
+	//             / \
+	//            5  6
+	//            |
+	//            7
+	//            |
+	//            8
+	//           / \
+	// 2 votes->9  10
+	f.ProcessAttestation(context.Background(), []uint64{0, 1}, indexToHash(9), 5)
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(10), indexToHash(8), 2, 2))
+
+	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 2)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(9), r, "Incorrect head for with justified epoch at 2")
+
+	// Add 3 more validators to the system.
+	balances = []uint64{1, 1, 1, 1, 1}
+	// The new validators voted for 10.
+	f.ProcessAttestation(context.Background(), []uint64{2, 3, 4}, indexToHash(10), 5)
+	// The new head should be 10.
+	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 2)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(10), r, "Incorrect head for with justified epoch at 2")
+
+	// Set the balances of the last 2 validators to 0.
+	balances = []uint64{1, 1, 1, 0, 0}
+	// The head should be back to 9.
+	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 2)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(9), r, "Incorrect head for with justified epoch at 1")
+
+	// Set the balances back to normal.
+	balances = []uint64{1, 1, 1, 1, 1}
+	// The head should be back to 10.
+	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 2)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(10), r, "Incorrect head for with justified epoch at 2")
+
+	// Remove the last 2 validators.
+	balances = []uint64{1, 1, 1}
+	// The head should be back to 9.
+	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 2)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(9), r, "Incorrect head for with justified epoch at 1")
+
+	// Verify pruning below the prune threshold does not affect head.
+	f.store.pruneThreshold = 1000
+	require.NoError(t, f.store.prune(context.Background(), indexToHash(5)))
+	assert.Equal(t, 11, len(f.store.nodeByRoot), "Incorrect nodes length after prune")
+
+	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 2)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(9), r, "Incorrect head for with justified epoch at 2")
+
+	// Verify pruning above the prune threshold does prune:
+	//          0
+	//         / \
+	//        2   1
+	//            |
+	//            3
+	//            |
+	//            4
+	// -------pruned here ------
+	//          5   6
+	//          |
+	//          7
+	//          |
+	//          8
+	//         / \
+	//        9  10
+	f.store.pruneThreshold = 1
+	require.NoError(t, f.store.prune(context.Background(), indexToHash(5)))
+	assert.Equal(t, 5, len(f.store.nodeByRoot), "Incorrect nodes length after prune")
+
+	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 2)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(9), r, "Incorrect head for with justified epoch at 2")
+
+	// Insert new block 11 and verify head is at 11.
+	//          5   6
+	//          |
+	//          7
+	//          |
+	//          8
+	//         / \
+	//        9  10
+	//        |
+	// head-> 11
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(11), indexToHash(9), 2, 2))
+
+	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 2)
+	require.NoError(t, err)
+	assert.Equal(t, indexToHash(11), r, "Incorrect head for with justified epoch at 2")
+}

beacon-chain/forkchoice/interfaces.go

@@ -5,7 +5,8 @@ import (
 	"time"
 
 	types "github.com/prysmaticlabs/eth2-types"
-	"github.com/prysmaticlabs/prysm/beacon-chain/forkchoice/protoarray"
+	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
+	pbrpc "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 )
 
 // ForkChoicer represents the full fork choice interface composed of all the sub-interfaces.
@@ -15,19 +16,26 @@ type ForkChoicer interface {
 	AttestationProcessor // to track new attestation for fork choice.
 	Pruner               // to clean old data for fork choice.
 	Getter               // to retrieve fork choice information.
+	Setter               // to set fork choice information.
 	ProposerBooster      // ability to boost timely-proposed block roots.
-	SyncTipper           // to update and retrieve validated sync tips.
 }
 
 // HeadRetriever retrieves head root and optimistic info of the current chain.
 type HeadRetriever interface {
 	Head(context.Context, types.Epoch, [32]byte, []uint64, types.Epoch) ([32]byte, error)
-	Optimistic(ctx context.Context, root [32]byte, slot types.Slot) (bool, error)
+	Tips() ([][32]byte, []types.Slot)
+	IsOptimistic(ctx context.Context, root [32]byte) (bool, error)
 }
 
 // BlockProcessor processes the block that's used for accounting fork choice.
 type BlockProcessor interface {
-	ProcessBlock(context.Context, types.Slot, [32]byte, [32]byte, [32]byte, types.Epoch, types.Epoch) error
+	InsertOptimisticBlock(ctx context.Context,
+		slot types.Slot,
+		root [32]byte,
+		parentRoot [32]byte,
+		justifiedEpoch types.Epoch,
+		finalizedEpoch types.Epoch,
+	) error
 }
 
 // AttestationProcessor processes the attestation that's used for accounting fork choice.
@@ -48,19 +56,19 @@ type ProposerBooster interface {
 
 // Getter returns fork choice related information.
 type Getter interface {
-	Nodes() []*protoarray.Node
-	Node([32]byte) *protoarray.Node
 	HasNode([32]byte) bool
-	Store() *protoarray.Store
+	ProposerBoost() [fieldparams.RootLength]byte
 	HasParent(root [32]byte) bool
 	AncestorRoot(ctx context.Context, root [32]byte, slot types.Slot) ([]byte, error)
 	IsCanonical(root [32]byte) bool
+	FinalizedEpoch() types.Epoch
+	JustifiedEpoch() types.Epoch
+	ForkChoiceNodes() []*pbrpc.ForkChoiceNode
+	NodeCount() int
 }
 
-// SyncTipper returns sync tips related information.
-type SyncTipper interface {
-	SyncedTips() map[[32]byte]types.Slot
-	SetSyncedTips(tips map[[32]byte]types.Slot) error
-	UpdateSyncedTipsWithValidRoot(ctx context.Context, root [32]byte) error
-	UpdateSyncedTipsWithInvalidRoot(ctx context.Context, root [32]byte) error
+// Setter allows to set forkchoice information
+type Setter interface {
+	SetOptimisticToValid(context.Context, [fieldparams.RootLength]byte) error
+	SetOptimisticToInvalid(context.Context, [fieldparams.RootLength]byte) error
 }

beacon-chain/forkchoice/protoarray/BUILD.bazel

@@ -21,7 +21,8 @@ go_library(
     deps = [
         "//config/fieldparams:go_default_library",
         "//config/params:go_default_library",
-        "//encoding/bytesutil:go_default_library",
+        "//math:go_default_library",
+        "//proto/prysm/v1alpha1:go_default_library",
         "//time/slots:go_default_library",
         "@com_github_pkg_errors//:go_default_library",
         "@com_github_prometheus_client_golang//prometheus:go_default_library",

beacon-chain/forkchoice/protoarray/errors.go

@@ -5,6 +5,7 @@ import "errors"
 var errUnknownFinalizedRoot = errors.New("unknown finalized root")
 var errUnknownJustifiedRoot = errors.New("unknown justified root")
 var errInvalidNodeIndex = errors.New("node index is invalid")
+var ErrUnknownNodeRoot = errors.New("unknown block root")
 var errInvalidJustifiedIndex = errors.New("justified index is invalid")
 var errInvalidBestChildIndex = errors.New("best child index is invalid")
 var errInvalidBestDescendantIndex = errors.New("best descendant index is invalid")

beacon-chain/forkchoice/protoarray/ffg_update_test.go

@@ -27,9 +27,9 @@ func TestFFGUpdates_OneBranch(t *testing.T) {
 	//            2 <- justified: 1, finalized: 0
 	//            |
 	//            3 <- justified: 2, finalized: 1
-	require.NoError(t, f.ProcessBlock(context.Background(), 1, indexToHash(1), params.BeaconConfig().ZeroHash, [32]byte{}, 0, 0))
-	require.NoError(t, f.ProcessBlock(context.Background(), 2, indexToHash(2), indexToHash(1), [32]byte{}, 1, 0))
-	require.NoError(t, f.ProcessBlock(context.Background(), 3, indexToHash(3), indexToHash(2), [32]byte{}, 2, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 2, indexToHash(2), indexToHash(1), 1, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 3, indexToHash(3), indexToHash(2), 2, 1))
 
 	// With starting justified epoch at 0, the head should be 3:
 	//            0 <- start
@@ -89,17 +89,17 @@ func TestFFGUpdates_TwoBranches(t *testing.T) {
 	//                              |   |
 	//  justified: 2, finalized: 0 -> 9  10 <- justified: 2, finalized: 0
 	// Left branch.
-	require.NoError(t, f.ProcessBlock(context.Background(), 1, indexToHash(1), params.BeaconConfig().ZeroHash, [32]byte{}, 0, 0))
-	require.NoError(t, f.ProcessBlock(context.Background(), 2, indexToHash(3), indexToHash(1), [32]byte{}, 1, 0))
-	require.NoError(t, f.ProcessBlock(context.Background(), 3, indexToHash(5), indexToHash(3), [32]byte{}, 1, 0))
-	require.NoError(t, f.ProcessBlock(context.Background(), 4, indexToHash(7), indexToHash(5), [32]byte{}, 1, 0))
-	require.NoError(t, f.ProcessBlock(context.Background(), 4, indexToHash(9), indexToHash(7), [32]byte{}, 2, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 1, indexToHash(1), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 2, indexToHash(3), indexToHash(1), 1, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 3, indexToHash(5), indexToHash(3), 1, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 4, indexToHash(7), indexToHash(5), 1, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 4, indexToHash(9), indexToHash(7), 2, 0))
 	// Right branch.
-	require.NoError(t, f.ProcessBlock(context.Background(), 1, indexToHash(2), params.BeaconConfig().ZeroHash, [32]byte{}, 0, 0))
-	require.NoError(t, f.ProcessBlock(context.Background(), 2, indexToHash(4), indexToHash(2), [32]byte{}, 0, 0))
-	require.NoError(t, f.ProcessBlock(context.Background(), 3, indexToHash(6), indexToHash(4), [32]byte{}, 0, 0))
-	require.NoError(t, f.ProcessBlock(context.Background(), 4, indexToHash(8), indexToHash(6), [32]byte{}, 1, 0))
-	require.NoError(t, f.ProcessBlock(context.Background(), 4, indexToHash(10), indexToHash(8), [32]byte{}, 2, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 1, indexToHash(2), params.BeaconConfig().ZeroHash, 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 2, indexToHash(4), indexToHash(2), 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 3, indexToHash(6), indexToHash(4), 0, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 4, indexToHash(8), indexToHash(6), 1, 0))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 4, indexToHash(10), indexToHash(8), 2, 0))
 
 	// With start at 0, the head should be 10:
 	//           0  <-- start
@@ -183,7 +183,7 @@ func TestFFGUpdates_TwoBranches(t *testing.T) {
 }
 
 func setup(justifiedEpoch, finalizedEpoch types.Epoch) *ForkChoice {
-	f := New(0, 0, params.BeaconConfig().ZeroHash)
+	f := New(justifiedEpoch, finalizedEpoch, params.BeaconConfig().ZeroHash)
 	f.store.nodesIndices[params.BeaconConfig().ZeroHash] = 0
 	f.store.nodes = append(f.store.nodes, &Node{
 		slot:           0,

beacon-chain/forkchoice/protoarray/helpers.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/prysmaticlabs/prysm/config/params"
+	pmath "github.com/prysmaticlabs/prysm/math"
 	"go.opencensus.io/trace"
 )
 
@@ -15,7 +16,7 @@ func computeDeltas(
 	votes []Vote,
 	oldBalances, newBalances []uint64,
 ) ([]int, []Vote, error) {
-	_, span := trace.StartSpan(ctx, "protoArrayForkChoice.computeDeltas")
+	_, span := trace.StartSpan(ctx, "doublyLinkedForkchoice.computeDeltas")
 	defer span.End()
 
 	deltas := make([]int, len(blockIndices))
@@ -46,19 +47,27 @@ func computeDeltas(
 			if ok {
 				// Protection against out of bound, the `nextDeltaIndex` which defines
 				// the block location in the dag can not exceed the total `delta` length.
-				if int(nextDeltaIndex) >= len(deltas) {
+				if nextDeltaIndex >= uint64(len(deltas)) {
 					return nil, nil, errInvalidNodeDelta
 				}
-				deltas[nextDeltaIndex] += int(newBalance)
+				delta, err := pmath.Int(newBalance)
+				if err != nil {
+					return nil, nil, err
+				}
+				deltas[nextDeltaIndex] += delta
 			}
 
 			currentDeltaIndex, ok := blockIndices[vote.currentRoot]
 			if ok {
 				// Protection against out of bound (same as above)
-				if int(currentDeltaIndex) >= len(deltas) {
+				if currentDeltaIndex >= uint64(len(deltas)) {
 					return nil, nil, errInvalidNodeDelta
 				}
-				deltas[currentDeltaIndex] -= int(oldBalance)
+				delta, err := pmath.Int(oldBalance)
+				if err != nil {
+					return nil, nil, err
+				}
+				deltas[currentDeltaIndex] -= delta
 			}
 		}
 

beacon-chain/forkchoice/protoarray/no_vote_test.go

@@ -24,7 +24,7 @@ func TestNoVote_CanFindHead(t *testing.T) {
 	//         0
 	//        /
 	//       2 <- head
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(2), params.BeaconConfig().ZeroHash, [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(2), params.BeaconConfig().ZeroHash, 1, 1))
 	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
 	require.NoError(t, err)
 	assert.Equal(t, indexToHash(2), r, "Incorrect head for with justified epoch at 1")
@@ -33,7 +33,7 @@ func TestNoVote_CanFindHead(t *testing.T) {
 	//            0
 	//           / \
 	//  head -> 2  1
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(1), params.BeaconConfig().ZeroHash, [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
 	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
 	require.NoError(t, err)
 	assert.Equal(t, indexToHash(2), r, "Incorrect head for with justified epoch at 1")
@@ -44,7 +44,7 @@ func TestNoVote_CanFindHead(t *testing.T) {
 	//  head -> 2  1
 	//             |
 	//             3
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(3), indexToHash(1), [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(3), indexToHash(1), 1, 1))
 	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
 	require.NoError(t, err)
 	assert.Equal(t, indexToHash(2), r, "Incorrect head for with justified epoch at 1")
@@ -55,7 +55,7 @@ func TestNoVote_CanFindHead(t *testing.T) {
 	//          2  1
 	//          |  |
 	//  head -> 4  3
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(4), indexToHash(2), [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(4), indexToHash(2), 1, 1))
 	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
 	require.NoError(t, err)
 	assert.Equal(t, indexToHash(4), r, "Incorrect head for with justified epoch at 1")
@@ -68,7 +68,7 @@ func TestNoVote_CanFindHead(t *testing.T) {
 	//  head -> 4  3
 	//          |
 	//          5 <- justified epoch = 2
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(5), indexToHash(4), [32]byte{}, 2, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(5), indexToHash(4), 2, 1))
 	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
 	require.NoError(t, err)
 	assert.Equal(t, indexToHash(4), r, "Incorrect head for with justified epoch at 1")
@@ -107,7 +107,7 @@ func TestNoVote_CanFindHead(t *testing.T) {
 	//          5
 	//          |
 	//          6 <- head
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(6), indexToHash(5), [32]byte{}, 2, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(6), indexToHash(5), 2, 1))
 	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 1)
 	require.NoError(t, err)
 	assert.Equal(t, indexToHash(6), r, "Incorrect head for with justified epoch at 2")

beacon-chain/forkchoice/protoarray/optimistic_sync.go

@@ -2,11 +2,9 @@ package protoarray
 
 import (
 	"context"
-	"fmt"
 
 	types "github.com/prysmaticlabs/eth2-types"
 	"github.com/prysmaticlabs/prysm/config/params"
-	"github.com/prysmaticlabs/prysm/encoding/bytesutil"
 )
 
 // This returns the minimum and maximum slot of the synced_tips tree
@@ -27,27 +25,32 @@ func (f *ForkChoice) boundarySyncedTips() (types.Slot, types.Slot) {
 	return min, max
 }
 
-// Optimistic returns true if this node is optimistically synced
+// IsOptimistic returns true if this node is optimistically synced
 // A optimistically synced block is synced as usual, but its
 // execution payload is not validated, while the EL is still syncing.
-// WARNING: this function does not check if slot corresponds to the
-//          block with the given root. An incorrect response may be
-//          returned when requesting earlier than finalized epoch due
-//          to pruning of non-canonical branches. A requests for a
-//          combination root/slot of an available block is guaranteed
-//          to yield the correct result. The caller is responsible for
-//          checking the block's availability. A consensus bug could be
-//          a cause of getting this wrong, so think twice before passing
-//          a wrong pair.
-func (f *ForkChoice) Optimistic(ctx context.Context, root [32]byte, slot types.Slot) (bool, error) {
+// This function returns an error if the block is not found in the fork choice
+// store
+func (f *ForkChoice) IsOptimistic(ctx context.Context, root [32]byte) (bool, error) {
 	if ctx.Err() != nil {
 		return false, ctx.Err()
 	}
+	// If we reached this point then the block has to be in the Fork Choice
+	// Store!
+	f.store.nodesLock.RLock()
+	index, ok := f.store.nodesIndices[root]
+	if !ok {
+		f.store.nodesLock.RUnlock()
+		return false, ErrUnknownNodeRoot
+	}
+	node := f.store.nodes[index]
+	slot := node.slot
+
 	// If the node is a synced tip, then it's fully validated
 	f.syncedTips.RLock()
-	_, ok := f.syncedTips.validatedTips[root]
+	_, ok = f.syncedTips.validatedTips[root]
 	if ok {
 		f.syncedTips.RUnlock()
+		f.store.nodesLock.RUnlock()
 		return false, nil
 	}
 	f.syncedTips.RUnlock()
@@ -55,39 +58,29 @@ func (f *ForkChoice) Optimistic(ctx context.Context, root [32]byte, slot types.S
 	// If the slot is higher than the max synced tip, it's optimistic
 	min, max := f.boundarySyncedTips()
 	if slot > max {
+		f.store.nodesLock.RUnlock()
 		return true, nil
 	}
 
 	// If the slot is lower than the min synced tip, it's fully validated
 	if slot <= min {
+		f.store.nodesLock.RUnlock()
 		return false, nil
 	}
 
-	// If we reached this point then the block has to be in the Fork Choice
-	// Store!
-	f.store.nodesLock.RLock()
-	index, ok := f.store.nodesIndices[root]
-	if !ok {
-		// This should not happen
-		f.store.nodesLock.RUnlock()
-		return false, fmt.Errorf("invalid root, slot combination, got %#x, %d",
-			bytesutil.Trunc(root[:]), slot)
-	}
-	node := f.store.nodes[index]
-
 	// if the node is a leaf of the Fork Choice tree, then it's
 	// optimistic
 	childIndex := node.BestChild()
 	if childIndex == NonExistentNode {
+		f.store.nodesLock.RUnlock()
 		return true, nil
 	}
 
 	// recurse to the child
 	child := f.store.nodes[childIndex]
 	root = child.root
-	slot = child.slot
 	f.store.nodesLock.RUnlock()
-	return f.Optimistic(ctx, root, slot)
+	return f.IsOptimistic(ctx, root)
 }
 
 // This function returns the index of sync tip node that's ancestor to the input node.
@@ -108,10 +101,10 @@ func (s *Store) findSyncedTip(ctx context.Context, node *Node, syncedTips *optim
 	}
 }
 
-// UpdateSyncedTipsWithValidRoot is called with the root of a block that was returned as
+// SetOptimisticToValid is called with the root of a block that was returned as
 // VALID by the EL. This routine recomputes and updates the synced_tips map to
 // account for this new tip.
-func (f *ForkChoice) UpdateSyncedTipsWithValidRoot(ctx context.Context, root [32]byte) error {
+func (f *ForkChoice) SetOptimisticToValid(ctx context.Context, root [32]byte) error {
 	f.store.nodesLock.RLock()
 	defer f.store.nodesLock.RUnlock()
 	// We can only update if given root is in Fork Choice
@@ -212,8 +205,8 @@ func (f *ForkChoice) UpdateSyncedTipsWithValidRoot(ctx context.Context, root [32
 	return nil
 }
 
-// UpdateSyncedTipsWithInvalidRoot updates the synced_tips map when the block with the given root becomes INVALID.
-func (f *ForkChoice) UpdateSyncedTipsWithInvalidRoot(ctx context.Context, root [32]byte) error {
+//  SetOptimisticToInvalid updates the synced_tips map when the block with the given root becomes INVALID.
+func (f *ForkChoice) SetOptimisticToInvalid(ctx context.Context, root [32]byte) error {
 	f.store.nodesLock.Lock()
 	defer f.store.nodesLock.Unlock()
 	idx, ok := f.store.nodesIndices[root]

beacon-chain/forkchoice/protoarray/optimistic_sync_test.go

@@ -28,9 +28,7 @@ import (
 
 func TestOptimistic(t *testing.T) {
 	root0 := bytesutil.ToBytes32([]byte("hello0"))
-	slot0 := types.Slot(98)
 	root1 := bytesutil.ToBytes32([]byte("hello1"))
-	slot1 := types.Slot(99)
 
 	nodeA := &Node{
 		slot:      types.Slot(100),
@@ -148,56 +146,54 @@ func TestOptimistic(t *testing.T) {
 	require.Equal(t, max, types.Slot(103), "maximum tip slot is different")
 
 	// We test first nodes outside the Fork Choice store
-	op, err := f.Optimistic(ctx, root0, slot0)
-	require.NoError(t, err)
-	require.Equal(t, op, false)
+	_, err := f.IsOptimistic(ctx, root0)
+	require.ErrorIs(t, ErrUnknownNodeRoot, err)
 
-	op, err = f.Optimistic(ctx, root1, slot1)
-	require.NoError(t, err)
-	require.Equal(t, op, false)
+	_, err = f.IsOptimistic(ctx, root1)
+	require.ErrorIs(t, ErrUnknownNodeRoot, err)
 
 	// We check all nodes in the Fork Choice store.
-	op, err = f.Optimistic(ctx, nodeA.root, nodeA.slot)
+	op, err := f.IsOptimistic(ctx, nodeA.root)
 	require.NoError(t, err)
 	require.Equal(t, op, false)
 
-	op, err = f.Optimistic(ctx, nodeB.root, nodeB.slot)
+	op, err = f.IsOptimistic(ctx, nodeB.root)
 	require.NoError(t, err)
 	require.Equal(t, op, false)
 
-	op, err = f.Optimistic(ctx, nodeC.root, nodeC.slot)
+	op, err = f.IsOptimistic(ctx, nodeC.root)
 	require.NoError(t, err)
 	require.Equal(t, op, false)
 
-	op, err = f.Optimistic(ctx, nodeD.root, nodeD.slot)
+	op, err = f.IsOptimistic(ctx, nodeD.root)
 	require.NoError(t, err)
 	require.Equal(t, op, false)
 
-	op, err = f.Optimistic(ctx, nodeE.root, nodeE.slot)
+	op, err = f.IsOptimistic(ctx, nodeE.root)
 	require.NoError(t, err)
 	require.Equal(t, op, true)
 
-	op, err = f.Optimistic(ctx, nodeF.root, nodeF.slot)
+	op, err = f.IsOptimistic(ctx, nodeF.root)
 	require.NoError(t, err)
 	require.Equal(t, op, true)
 
-	op, err = f.Optimistic(ctx, nodeG.root, nodeG.slot)
+	op, err = f.IsOptimistic(ctx, nodeG.root)
 	require.NoError(t, err)
 	require.Equal(t, op, true)
 
-	op, err = f.Optimistic(ctx, nodeH.root, nodeH.slot)
+	op, err = f.IsOptimistic(ctx, nodeH.root)
 	require.NoError(t, err)
 	require.Equal(t, op, true)
 
-	op, err = f.Optimistic(ctx, nodeI.root, nodeI.slot)
+	op, err = f.IsOptimistic(ctx, nodeI.root)
 	require.NoError(t, err)
 	require.Equal(t, op, true)
 
-	op, err = f.Optimistic(ctx, nodeJ.root, nodeJ.slot)
+	op, err = f.IsOptimistic(ctx, nodeJ.root)
 	require.NoError(t, err)
 	require.Equal(t, op, true)
 
-	op, err = f.Optimistic(ctx, nodeK.root, nodeK.slot)
+	op, err = f.IsOptimistic(ctx, nodeK.root)
 	require.NoError(t, err)
 	require.Equal(t, op, true)
 
@@ -220,22 +216,22 @@ func TestOptimistic(t *testing.T) {
 // And every block in the Fork choice is optimistic. Synced_Tips contains a
 // single block that is outside of Fork choice
 //
-func TestUpdateSyncTipsWithValidRoots(t *testing.T) {
+func TestSetOptimisticToValid(t *testing.T) {
 	ctx := context.Background()
 	f := setup(1, 1)
 
-	require.NoError(t, f.ProcessBlock(ctx, 100, [32]byte{'a'}, params.BeaconConfig().ZeroHash, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 102, [32]byte{'j'}, [32]byte{'b'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 103, [32]byte{'d'}, [32]byte{'c'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 104, [32]byte{'e'}, [32]byte{'d'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 104, [32]byte{'g'}, [32]byte{'d'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 105, [32]byte{'f'}, [32]byte{'e'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 105, [32]byte{'h'}, [32]byte{'g'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 105, [32]byte{'k'}, [32]byte{'g'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 106, [32]byte{'i'}, [32]byte{'h'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 106, [32]byte{'l'}, [32]byte{'k'}, [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'j'}, [32]byte{'b'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 103, [32]byte{'d'}, [32]byte{'c'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 104, [32]byte{'e'}, [32]byte{'d'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 104, [32]byte{'g'}, [32]byte{'d'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'f'}, [32]byte{'e'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'h'}, [32]byte{'g'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'k'}, [32]byte{'g'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 106, [32]byte{'i'}, [32]byte{'h'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 106, [32]byte{'l'}, [32]byte{'k'}, 1, 1))
 	tests := []struct {
 		root      [32]byte                // the root of the new VALID block
 		tips      map[[32]byte]types.Slot // the old synced tips
@@ -325,7 +321,7 @@ func TestUpdateSyncTipsWithValidRoots(t *testing.T) {
 		f.syncedTips.Lock()
 		f.syncedTips.validatedTips = tc.tips
 		f.syncedTips.Unlock()
-		err := f.UpdateSyncedTipsWithValidRoot(context.Background(), tc.root)
+		err := f.SetOptimisticToValid(context.Background(), tc.root)
 		if tc.wantedErr != nil {
 			require.ErrorIs(t, err, tc.wantedErr)
 		} else {
@@ -352,7 +348,7 @@ func TestUpdateSyncTipsWithValidRoots(t *testing.T) {
 // single block that is outside of Fork choice. The numbers in parentheses are
 // the weights of the nodes before removal
 //
-func TestUpdateSyncTipsWithInvalidRoot(t *testing.T) {
+func TestSetOptimisticToInvalid(t *testing.T) {
 	tests := []struct {
 		root              [32]byte                // the root of the new INVALID block
 		tips              map[[32]byte]types.Slot // the old synced tips
@@ -413,18 +409,18 @@ func TestUpdateSyncTipsWithInvalidRoot(t *testing.T) {
 		ctx := context.Background()
 		f := setup(1, 1)
 
-		require.NoError(t, f.ProcessBlock(ctx, 100, [32]byte{'a'}, params.BeaconConfig().ZeroHash, [32]byte{}, 1, 1))
-		require.NoError(t, f.ProcessBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, [32]byte{}, 1, 1))
-		require.NoError(t, f.ProcessBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, [32]byte{}, 1, 1))
-		require.NoError(t, f.ProcessBlock(ctx, 102, [32]byte{'j'}, [32]byte{'b'}, [32]byte{}, 1, 1))
-		require.NoError(t, f.ProcessBlock(ctx, 103, [32]byte{'d'}, [32]byte{'c'}, [32]byte{}, 1, 1))
-		require.NoError(t, f.ProcessBlock(ctx, 104, [32]byte{'e'}, [32]byte{'d'}, [32]byte{}, 1, 1))
-		require.NoError(t, f.ProcessBlock(ctx, 104, [32]byte{'g'}, [32]byte{'d'}, [32]byte{}, 1, 1))
-		require.NoError(t, f.ProcessBlock(ctx, 105, [32]byte{'f'}, [32]byte{'e'}, [32]byte{}, 1, 1))
-		require.NoError(t, f.ProcessBlock(ctx, 105, [32]byte{'h'}, [32]byte{'g'}, [32]byte{}, 1, 1))
-		require.NoError(t, f.ProcessBlock(ctx, 105, [32]byte{'k'}, [32]byte{'g'}, [32]byte{}, 1, 1))
-		require.NoError(t, f.ProcessBlock(ctx, 106, [32]byte{'i'}, [32]byte{'h'}, [32]byte{}, 1, 1))
-		require.NoError(t, f.ProcessBlock(ctx, 106, [32]byte{'l'}, [32]byte{'k'}, [32]byte{}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'j'}, [32]byte{'b'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 103, [32]byte{'d'}, [32]byte{'c'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 104, [32]byte{'e'}, [32]byte{'d'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 104, [32]byte{'g'}, [32]byte{'d'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'f'}, [32]byte{'e'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'h'}, [32]byte{'g'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'k'}, [32]byte{'g'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 106, [32]byte{'i'}, [32]byte{'h'}, 1, 1))
+		require.NoError(t, f.InsertOptimisticBlock(ctx, 106, [32]byte{'l'}, [32]byte{'k'}, 1, 1))
 		weights := []uint64{10, 10, 9, 7, 1, 6, 2, 3, 1, 1, 1, 0, 0}
 		f.syncedTips.Lock()
 		f.syncedTips.validatedTips = tc.tips
@@ -443,7 +439,7 @@ func TestUpdateSyncTipsWithInvalidRoot(t *testing.T) {
 		require.NotEqual(t, NonExistentNode, parentIndex)
 		parent := f.store.nodes[parentIndex]
 		f.store.nodesLock.Unlock()
-		err := f.UpdateSyncedTipsWithInvalidRoot(context.Background(), tc.root)
+		err := f.SetOptimisticToInvalid(context.Background(), tc.root)
 		require.NoError(t, err)
 		f.syncedTips.RLock()
 		_, parentSyncedTip := f.syncedTips.validatedTips[parent.root]
@@ -471,18 +467,18 @@ func TestFindSyncedTip(t *testing.T) {
 	ctx := context.Background()
 	f := setup(1, 1)
 
-	require.NoError(t, f.ProcessBlock(ctx, 100, [32]byte{'a'}, params.BeaconConfig().ZeroHash, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 102, [32]byte{'j'}, [32]byte{'b'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 103, [32]byte{'d'}, [32]byte{'c'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 104, [32]byte{'e'}, [32]byte{'d'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 104, [32]byte{'g'}, [32]byte{'d'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 105, [32]byte{'f'}, [32]byte{'e'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 105, [32]byte{'h'}, [32]byte{'g'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 105, [32]byte{'k'}, [32]byte{'g'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 106, [32]byte{'i'}, [32]byte{'h'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 106, [32]byte{'l'}, [32]byte{'k'}, [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'j'}, [32]byte{'b'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 103, [32]byte{'d'}, [32]byte{'c'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 104, [32]byte{'e'}, [32]byte{'d'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 104, [32]byte{'g'}, [32]byte{'d'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'f'}, [32]byte{'e'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'h'}, [32]byte{'g'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'k'}, [32]byte{'g'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 106, [32]byte{'i'}, [32]byte{'h'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 106, [32]byte{'l'}, [32]byte{'k'}, 1, 1))
 	tests := []struct {
 		root   [32]byte                // the root of the block
 		tips   map[[32]byte]types.Slot // the synced tips
@@ -552,3 +548,45 @@ func TestFindSyncedTip(t *testing.T) {
 		syncedTips.RUnlock()
 	}
 }
+
+// This is a regression test (10341)
+func TestIsOptimistic_DeadLock(t *testing.T) {
+	ctx := context.Background()
+	f := setup(1, 1)
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 90, [32]byte{'b'}, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 101, [32]byte{'c'}, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'d'}, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 103, [32]byte{'e'}, params.BeaconConfig().ZeroHash, 1, 1))
+	tips := map[[32]byte]types.Slot{
+		[32]byte{'a'}: 100,
+		[32]byte{'d'}: 102,
+	}
+	f.syncedTips.validatedTips = tips
+	_, err := f.IsOptimistic(ctx, [32]byte{'a'})
+	require.NoError(t, err)
+
+	// Acquire a write lock, this should not hang
+	f.store.nodesLock.Lock()
+	f.store.nodesLock.Unlock()
+	_, err = f.IsOptimistic(ctx, [32]byte{'e'})
+	require.NoError(t, err)
+
+	// Acquire a write lock, this should not hang
+	f.store.nodesLock.Lock()
+	f.store.nodesLock.Unlock()
+	_, err = f.IsOptimistic(ctx, [32]byte{'b'})
+	require.NoError(t, err)
+
+	// Acquire a write lock, this should not hang
+	f.store.nodesLock.Lock()
+	f.store.nodesLock.Unlock()
+
+	_, err = f.IsOptimistic(ctx, [32]byte{'c'})
+	require.NoError(t, err)
+
+	// Acquire a write lock, this should not hang
+	f.store.nodesLock.Lock()
+	f.store.nodesLock.Unlock()
+
+}

beacon-chain/forkchoice/protoarray/proposer_boost_test.go

@@ -21,7 +21,6 @@ import (
 func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
 	ctx := context.Background()
 	zeroHash := params.BeaconConfig().ZeroHash
-	graffiti := [32]byte{}
 	balances := make([]uint64, 64) // 64 active validators.
 	for i := 0; i < len(balances); i++ {
 		balances[i] = 10
@@ -42,12 +41,11 @@ func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
 		slot := types.Slot(1)
 		newRoot := indexToHash(1)
 		require.NoError(t,
-			f.ProcessBlock(
+			f.InsertOptimisticBlock(
 				ctx,
 				slot,
 				newRoot,
 				headRoot,
-				graffiti,
 				jEpoch,
 				fEpoch,
 			),
@@ -66,12 +64,11 @@ func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
 		slot = types.Slot(2)
 		newRoot = indexToHash(2)
 		require.NoError(t,
-			f.ProcessBlock(
+			f.InsertOptimisticBlock(
 				ctx,
 				slot,
 				newRoot,
 				headRoot,
-				graffiti,
 				jEpoch,
 				fEpoch,
 			),
@@ -92,12 +89,11 @@ func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
 		slot = types.Slot(2)
 		newRoot = indexToHash(2)
 		require.NoError(t,
-			f.ProcessBlock(
+			f.InsertOptimisticBlock(
 				ctx,
 				slot,
 				newRoot,
 				headRoot,
-				graffiti,
 				jEpoch,
 				fEpoch,
 			),
@@ -118,12 +114,11 @@ func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
 		slot = types.Slot(3)
 		newRoot = indexToHash(4)
 		require.NoError(t,
-			f.ProcessBlock(
+			f.InsertOptimisticBlock(
 				ctx,
 				slot,
 				newRoot,
 				headRoot,
-				graffiti,
 				jEpoch,
 				fEpoch,
 			),
@@ -185,12 +180,11 @@ func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
 		honestBlockSlot := types.Slot(2)
 		honestBlock := indexToHash(2)
 		require.NoError(t,
-			f.ProcessBlock(
+			f.InsertOptimisticBlock(
 				ctx,
 				honestBlockSlot,
 				honestBlock,
 				zeroHash,
-				graffiti,
 				jEpoch,
 				fEpoch,
 			),
@@ -202,12 +196,11 @@ func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
 		maliciouslyWithheldBlockSlot := types.Slot(1)
 		maliciouslyWithheldBlock := indexToHash(1)
 		require.NoError(t,
-			f.ProcessBlock(
+			f.InsertOptimisticBlock(
 				ctx,
 				maliciouslyWithheldBlockSlot,
 				maliciouslyWithheldBlock,
 				zeroHash,
-				graffiti,
 				jEpoch,
 				fEpoch,
 			),
@@ -251,12 +244,11 @@ func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
 		honestBlockSlot := types.Slot(2)
 		honestBlock := indexToHash(2)
 		require.NoError(t,
-			f.ProcessBlock(
+			f.InsertOptimisticBlock(
 				ctx,
 				honestBlockSlot,
 				honestBlock,
 				zeroHash,
-				graffiti,
 				jEpoch,
 				fEpoch,
 			),
@@ -270,12 +262,11 @@ func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
 		maliciouslyWithheldBlockSlot := types.Slot(1)
 		maliciouslyWithheldBlock := indexToHash(1)
 		require.NoError(t,
-			f.ProcessBlock(
+			f.InsertOptimisticBlock(
 				ctx,
 				maliciouslyWithheldBlockSlot,
 				maliciouslyWithheldBlock,
 				zeroHash,
-				graffiti,
 				jEpoch,
 				fEpoch,
 			),
@@ -326,12 +317,11 @@ func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
 		cSlot := types.Slot(2)
 		c := indexToHash(2)
 		require.NoError(t,
-			f.ProcessBlock(
+			f.InsertOptimisticBlock(
 				ctx,
 				cSlot,
 				c,
 				a, // parent
-				graffiti,
 				jEpoch,
 				fEpoch,
 			),
@@ -350,12 +340,11 @@ func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
 		bSlot := types.Slot(1)
 		b := indexToHash(1)
 		require.NoError(t,
-			f.ProcessBlock(
+			f.InsertOptimisticBlock(
 				ctx,
 				bSlot,
 				b,
 				a, // parent
-				graffiti,
 				jEpoch,
 				fEpoch,
 			),
@@ -374,12 +363,11 @@ func TestForkChoice_BoostProposerRoot_PreventsExAnteAttack(t *testing.T) {
 		dSlot := types.Slot(3)
 		d := indexToHash(3)
 		require.NoError(t,
-			f.ProcessBlock(
+			f.InsertOptimisticBlock(
 				ctx,
 				dSlot,
 				d,
 				b, // parent
-				graffiti,
 				jEpoch,
 				fEpoch,
 			),

beacon-chain/forkchoice/protoarray/store.go

@@ -9,6 +9,8 @@ import (
 	types "github.com/prysmaticlabs/eth2-types"
 	fieldparams "github.com/prysmaticlabs/prysm/config/fieldparams"
 	"github.com/prysmaticlabs/prysm/config/params"
+	pmath "github.com/prysmaticlabs/prysm/math"
+	pbrpc "github.com/prysmaticlabs/prysm/proto/prysm/v1alpha1"
 	"go.opencensus.io/trace"
 )
 
@@ -130,17 +132,28 @@ func (f *ForkChoice) ProcessAttestation(ctx context.Context, validatorIndices []
 	processedAttestationCount.Inc()
 }
 
-// ProcessBlock processes a new block by inserting it to the fork choice store.
-func (f *ForkChoice) ProcessBlock(
+// NodeCount returns the current number of nodes in the Store
+func (f *ForkChoice) NodeCount() int {
+	f.store.nodesLock.RLock()
+	defer f.store.nodesLock.RUnlock()
+	return len(f.store.nodes)
+}
+
+// ProposerBoost returns the proposerBoost of the store
+func (f *ForkChoice) ProposerBoost() [fieldparams.RootLength]byte {
+	return f.store.proposerBoost()
+}
+
+// InsertOptimisticBlock processes a new block by inserting it to the fork choice store.
+func (f *ForkChoice) InsertOptimisticBlock(
 	ctx context.Context,
 	slot types.Slot,
-	blockRoot, parentRoot, graffiti [32]byte,
-	justifiedEpoch, finalizedEpoch types.Epoch,
-) error {
-	ctx, span := trace.StartSpan(ctx, "protoArrayForkChoice.ProcessBlock")
+	blockRoot, parentRoot [32]byte,
+	justifiedEpoch, finalizedEpoch types.Epoch) error {
+	ctx, span := trace.StartSpan(ctx, "protoArrayForkChoice.InsertOptimisticBlock")
 	defer span.End()
 
-	return f.store.insert(ctx, slot, blockRoot, parentRoot, graffiti, justifiedEpoch, finalizedEpoch)
+	return f.store.insert(ctx, slot, blockRoot, parentRoot, justifiedEpoch, finalizedEpoch)
 }
 
 // Prune prunes the fork choice store with the new finalized root. The store is only pruned if the input
@@ -149,36 +162,6 @@ func (f *ForkChoice) Prune(ctx context.Context, finalizedRoot [32]byte) error {
 	return f.store.prune(ctx, finalizedRoot, f.syncedTips)
 }
 
-// Nodes returns the copied list of block nodes in the fork choice store.
-func (f *ForkChoice) Nodes() []*Node {
-	f.store.nodesLock.RLock()
-	defer f.store.nodesLock.RUnlock()
-
-	cpy := make([]*Node, len(f.store.nodes))
-	copy(cpy, f.store.nodes)
-	return cpy
-}
-
-// Store returns the fork choice store object which contains all the information regarding proto array fork choice.
-func (f *ForkChoice) Store() *Store {
-	f.store.nodesLock.Lock()
-	defer f.store.nodesLock.Unlock()
-	return f.store
-}
-
-// Node returns the copied node in the fork choice store.
-func (f *ForkChoice) Node(root [32]byte) *Node {
-	f.store.nodesLock.RLock()
-	defer f.store.nodesLock.RUnlock()
-
-	index, ok := f.store.nodesIndices[root]
-	if !ok {
-		return nil
-	}
-
-	return copyNode(f.store.nodes[index])
-}
-
 // HasNode returns true if the node exists in fork choice store,
 // false else wise.
 func (f *ForkChoice) HasNode(root [32]byte) bool {
@@ -248,36 +231,22 @@ func (s *Store) PruneThreshold() uint64 {
 }
 
 // JustifiedEpoch of fork choice store.
-func (s *Store) JustifiedEpoch() types.Epoch {
-	return s.justifiedEpoch
+func (f *ForkChoice) JustifiedEpoch() types.Epoch {
+	return f.store.justifiedEpoch
 }
 
 // FinalizedEpoch of fork choice store.
-func (s *Store) FinalizedEpoch() types.Epoch {
-	return s.finalizedEpoch
+func (f *ForkChoice) FinalizedEpoch() types.Epoch {
+	return f.store.finalizedEpoch
 }
 
-// ProposerBoost of fork choice store.
-func (s *Store) ProposerBoost() [fieldparams.RootLength]byte {
+// proposerBoost of fork choice store.
+func (s *Store) proposerBoost() [fieldparams.RootLength]byte {
 	s.proposerBoostLock.RLock()
 	defer s.proposerBoostLock.RUnlock()
 	return s.proposerBoostRoot
 }
 
-// Nodes of fork choice store.
-func (s *Store) Nodes() []*Node {
-	s.nodesLock.RLock()
-	defer s.nodesLock.RUnlock()
-	return s.nodes
-}
-
-// NodesIndices of fork choice store.
-func (s *Store) NodesIndices() map[[32]byte]uint64 {
-	s.nodesLock.RLock()
-	defer s.nodesLock.RUnlock()
-	return s.nodesIndices
-}
-
 // head starts from justified root and then follows the best descendant links
 // to find the best block for head.
 func (s *Store) head(ctx context.Context, justifiedRoot [32]byte) ([32]byte, error) {
@@ -373,7 +342,7 @@ func (s *Store) updateCanonicalNodes(ctx context.Context, root [32]byte) error {
 // It then updates the new node's parent with best child and descendant node.
 func (s *Store) insert(ctx context.Context,
 	slot types.Slot,
-	root, parent, graffiti [32]byte,
+	root, parent [32]byte,
 	justifiedEpoch, finalizedEpoch types.Epoch) error {
 	_, span := trace.StartSpan(ctx, "protoArrayForkChoice.insert")
 	defer span.End()
@@ -396,7 +365,6 @@ func (s *Store) insert(ctx context.Context,
 	n := &Node{
 		slot:           slot,
 		root:           root,
-		graffiti:       graffiti,
 		parent:         parentIndex,
 		justifiedEpoch: justifiedEpoch,
 		finalizedEpoch: finalizedEpoch,
@@ -472,7 +440,11 @@ func (s *Store) applyWeightChanges(
 				s.proposerBoostLock.Unlock()
 				return err
 			}
-			nodeDelta = nodeDelta + int(proposerScore)
+			iProposerScore, err := pmath.Int(proposerScore)
+			if err != nil {
+				return err
+			}
+			nodeDelta = nodeDelta + iProposerScore
 		}
 		s.proposerBoostLock.Unlock()
 
@@ -744,3 +716,60 @@ func (s *Store) leaves() ([]uint64, error) {
 	}
 	return leaves, nil
 }
+
+// Tips returns all possible chain heads (leaves of fork choice tree).
+// Heads roots and heads slots are returned.
+func (f *ForkChoice) Tips() ([][32]byte, []types.Slot) {
+
+	// Deliberate choice to not preallocate space for below.
+	// Heads cant be more than 2-3 in the worst case where pre-allocation will be 64 to begin with.
+	headsRoots := make([][32]byte, 0)
+	headsSlots := make([]types.Slot, 0)
+
+	f.store.nodesLock.RLock()
+	defer f.store.nodesLock.RUnlock()
+	for _, node := range f.store.nodes {
+		// Possible heads have no children.
+		if node.BestDescendant() == NonExistentNode && node.BestChild() == NonExistentNode {
+			headsRoots = append(headsRoots, node.Root())
+			headsSlots = append(headsSlots, node.Slot())
+		}
+	}
+	return headsRoots, headsSlots
+}
+
+func (f *ForkChoice) ForkChoiceNodes() []*pbrpc.ForkChoiceNode {
+	f.store.nodesLock.RLock()
+	defer f.store.nodesLock.RUnlock()
+	ret := make([]*pbrpc.ForkChoiceNode, len(f.store.nodes))
+	var parentRoot [32]byte
+	for i, node := range f.store.nodes {
+		root := node.Root()
+		parentIdx := node.parent
+		if parentIdx == NonExistentNode {
+			parentRoot = params.BeaconConfig().ZeroHash
+		} else {
+			parent := f.store.nodes[parentIdx]
+			parentRoot = parent.Root()
+		}
+		bestDescendantIdx := node.BestDescendant()
+		var bestDescendantRoot [32]byte
+		if bestDescendantIdx == NonExistentNode {
+			bestDescendantRoot = params.BeaconConfig().ZeroHash
+		} else {
+			bestDescendantNode := f.store.nodes[bestDescendantIdx]
+			bestDescendantRoot = bestDescendantNode.Root()
+		}
+
+		ret[i] = &pbrpc.ForkChoiceNode{
+			Slot:           node.Slot(),
+			Root:           root[:],
+			Parent:         parentRoot[:],
+			JustifiedEpoch: node.JustifiedEpoch(),
+			FinalizedEpoch: node.FinalizedEpoch(),
+			Weight:         node.Weight(),
+			BestDescendant: bestDescendantRoot[:],
+		}
+	}
+	return ret
+}

beacon-chain/forkchoice/protoarray/store_test.go

@@ -22,44 +22,14 @@ func TestStore_PruneThreshold(t *testing.T) {
 
 func TestStore_JustifiedEpoch(t *testing.T) {
 	j := types.Epoch(100)
-	s := &Store{
-		justifiedEpoch: j,
-	}
-	if got := s.JustifiedEpoch(); got != j {
-		t.Errorf("JustifiedEpoch() = %v, want %v", got, j)
-	}
+	f := setup(j, j)
+	require.Equal(t, j, f.JustifiedEpoch())
 }
 
 func TestStore_FinalizedEpoch(t *testing.T) {
-	f := types.Epoch(50)
-	s := &Store{
-		finalizedEpoch: f,
-	}
-	if got := s.FinalizedEpoch(); got != f {
-		t.Errorf("FinalizedEpoch() = %v, want %v", got, f)
-	}
-}
-
-func TestStore_Nodes(t *testing.T) {
-	nodes := []*Node{
-		{slot: 100},
-		{slot: 101},
-	}
-	s := &Store{
-		nodes: nodes,
-	}
-	require.DeepEqual(t, nodes, s.Nodes())
-}
-
-func TestStore_NodesIndices(t *testing.T) {
-	nodeIndices := map[[32]byte]uint64{
-		{'a'}: 1,
-		{'b'}: 2,
-	}
-	s := &Store{
-		nodesIndices: nodeIndices,
-	}
-	require.DeepEqual(t, nodeIndices, s.NodesIndices())
+	j := types.Epoch(50)
+	f := setup(j, j)
+	require.Equal(t, j, f.FinalizedEpoch())
 }
 
 func TestForkChoice_HasNode(t *testing.T) {
@@ -74,30 +44,6 @@ func TestForkChoice_HasNode(t *testing.T) {
 	require.Equal(t, true, f.HasNode([32]byte{'a'}))
 }
 
-func TestForkChoice_Store(t *testing.T) {
-	nodeIndices := map[[32]byte]uint64{
-		{'a'}: 1,
-		{'b'}: 2,
-	}
-	s := &Store{
-		nodesIndices: nodeIndices,
-	}
-	f := &ForkChoice{store: s}
-	require.DeepEqual(t, s, f.Store())
-}
-
-func TestForkChoice_Nodes(t *testing.T) {
-	nodes := []*Node{
-		{slot: 100},
-		{slot: 101},
-	}
-	s := &Store{
-		nodes: nodes,
-	}
-	f := &ForkChoice{store: s}
-	require.DeepEqual(t, s.nodes, f.Nodes())
-}
-
 func TestStore_Head_UnknownJustifiedRoot(t *testing.T) {
 	s := &Store{nodesIndices: make(map[[32]byte]uint64)}
 
@@ -155,7 +101,7 @@ func TestStore_Head_ContextCancelled(t *testing.T) {
 func TestStore_Insert_UnknownParent(t *testing.T) {
 	// The new node does not have a parent.
 	s := &Store{nodesIndices: make(map[[32]byte]uint64)}
-	require.NoError(t, s.insert(context.Background(), 100, [32]byte{'A'}, [32]byte{'B'}, [32]byte{}, 1, 1))
+	require.NoError(t, s.insert(context.Background(), 100, [32]byte{'A'}, [32]byte{'B'}, 1, 1))
 	assert.Equal(t, 1, len(s.nodes), "Did not insert block")
 	assert.Equal(t, 1, len(s.nodesIndices), "Did not insert block")
 	assert.Equal(t, NonExistentNode, s.nodes[0].parent, "Incorrect parent")
@@ -171,7 +117,7 @@ func TestStore_Insert_KnownParent(t *testing.T) {
 	s.nodes = []*Node{{}}
 	p := [32]byte{'B'}
 	s.nodesIndices[p] = 0
-	require.NoError(t, s.insert(context.Background(), 100, [32]byte{'A'}, p, [32]byte{}, 1, 1))
+	require.NoError(t, s.insert(context.Background(), 100, [32]byte{'A'}, p, 1, 1))
 	assert.Equal(t, 2, len(s.nodes), "Did not insert block")
 	assert.Equal(t, 2, len(s.nodesIndices), "Did not insert block")
 	assert.Equal(t, uint64(0), s.nodes[1].parent, "Incorrect parent")
@@ -545,18 +491,18 @@ func TestStore_PruneSyncedTips(t *testing.T) {
 	ctx := context.Background()
 	f := setup(1, 1)
 
-	require.NoError(t, f.ProcessBlock(ctx, 100, [32]byte{'a'}, params.BeaconConfig().ZeroHash, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 102, [32]byte{'j'}, [32]byte{'b'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 103, [32]byte{'d'}, [32]byte{'c'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 104, [32]byte{'e'}, [32]byte{'d'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 104, [32]byte{'g'}, [32]byte{'d'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 105, [32]byte{'f'}, [32]byte{'e'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 105, [32]byte{'h'}, [32]byte{'g'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 105, [32]byte{'k'}, [32]byte{'g'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 106, [32]byte{'i'}, [32]byte{'h'}, [32]byte{}, 1, 1))
-	require.NoError(t, f.ProcessBlock(ctx, 106, [32]byte{'l'}, [32]byte{'k'}, [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 100, [32]byte{'a'}, params.BeaconConfig().ZeroHash, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 101, [32]byte{'b'}, [32]byte{'a'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'c'}, [32]byte{'b'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 102, [32]byte{'j'}, [32]byte{'b'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 103, [32]byte{'d'}, [32]byte{'c'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 104, [32]byte{'e'}, [32]byte{'d'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 104, [32]byte{'g'}, [32]byte{'d'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'f'}, [32]byte{'e'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'h'}, [32]byte{'g'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 105, [32]byte{'k'}, [32]byte{'g'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 106, [32]byte{'i'}, [32]byte{'h'}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(ctx, 106, [32]byte{'l'}, [32]byte{'k'}, 1, 1))
 	syncedTips := &optimisticStore{
 		validatedTips: map[[32]byte]types.Slot{
 			[32]byte{'b'}: 101,
@@ -721,8 +667,10 @@ func TestStore_UpdateCanonicalNodes_WholeList(t *testing.T) {
 	require.Equal(t, true, f.IsCanonical([32]byte{'a'}))
 	require.Equal(t, true, f.IsCanonical([32]byte{'b'}))
 	require.Equal(t, true, f.IsCanonical([32]byte{'c'}))
-	require.DeepEqual(t, f.Node([32]byte{'c'}), f.store.nodes[2])
-	require.Equal(t, f.Node([32]byte{'d'}), (*Node)(nil))
+	idxc := f.store.nodesIndices[[32]byte{'c'}]
+	_, ok := f.store.nodesIndices[[32]byte{'d'}]
+	require.Equal(t, idxc, uint64(2))
+	require.Equal(t, false, ok)
 }
 
 func TestStore_UpdateCanonicalNodes_ParentAlreadyIn(t *testing.T) {

beacon-chain/forkchoice/protoarray/vote_test.go

@@ -23,7 +23,7 @@ func TestVotes_CanFindHead(t *testing.T) {
 	//         0
 	//        /
 	//       2 <- head
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(2), params.BeaconConfig().ZeroHash, [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(2), params.BeaconConfig().ZeroHash, 1, 1))
 
 	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
 	require.NoError(t, err)
@@ -33,7 +33,7 @@ func TestVotes_CanFindHead(t *testing.T) {
 	//            0
 	//           / \
 	//  head -> 2  1
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(1), params.BeaconConfig().ZeroHash, [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(1), params.BeaconConfig().ZeroHash, 1, 1))
 
 	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
 	require.NoError(t, err)
@@ -63,7 +63,7 @@ func TestVotes_CanFindHead(t *testing.T) {
 	//  head -> 2  1
 	//             |
 	//             3
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(3), indexToHash(1), [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(3), indexToHash(1), 1, 1))
 
 	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
 	require.NoError(t, err)
@@ -99,7 +99,7 @@ func TestVotes_CanFindHead(t *testing.T) {
 	//             3
 	//             |
 	//             4 <- head
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(4), indexToHash(3), [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(4), indexToHash(3), 1, 1))
 
 	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
 	require.NoError(t, err)
@@ -115,7 +115,7 @@ func TestVotes_CanFindHead(t *testing.T) {
 	//             4 <- head
 	//            /
 	//           5 <- justified epoch = 2
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(5), indexToHash(4), [32]byte{}, 2, 2))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(5), indexToHash(4), 2, 2))
 
 	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
 	require.NoError(t, err)
@@ -131,7 +131,7 @@ func TestVotes_CanFindHead(t *testing.T) {
 	//             4 <- head
 	//            / \
 	//           5  6 <- justified epoch = 0
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(6), indexToHash(4), [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(6), indexToHash(4), 1, 1))
 
 	// Moved 2 votes to block 5:
 	//            0
@@ -143,7 +143,7 @@ func TestVotes_CanFindHead(t *testing.T) {
 	//             4
 	//            / \
 	// 2 votes-> 5  6
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(6), indexToHash(4), [32]byte{}, 1, 1))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(6), indexToHash(4), 1, 1))
 
 	f.ProcessAttestation(context.Background(), []uint64{0, 1}, indexToHash(5), 4)
 
@@ -164,9 +164,9 @@ func TestVotes_CanFindHead(t *testing.T) {
 	//           8
 	//           |
 	//           9
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(7), indexToHash(5), [32]byte{}, 2, 2))
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(8), indexToHash(7), [32]byte{}, 2, 2))
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(9), indexToHash(8), [32]byte{}, 2, 2))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(7), indexToHash(5), 2, 2))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(8), indexToHash(7), 2, 2))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(9), indexToHash(8), 2, 2))
 
 	r, err = f.Head(context.Background(), 1, params.BeaconConfig().ZeroHash, balances, 1)
 	require.NoError(t, err)
@@ -211,7 +211,7 @@ func TestVotes_CanFindHead(t *testing.T) {
 	//           / \
 	// 2 votes->9  10
 	f.ProcessAttestation(context.Background(), []uint64{0, 1}, indexToHash(9), 5)
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(10), indexToHash(8), [32]byte{}, 2, 2))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(10), indexToHash(8), 2, 2))
 
 	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 2)
 	require.NoError(t, err)
@@ -290,7 +290,7 @@ func TestVotes_CanFindHead(t *testing.T) {
 	//        9  10
 	//        |
 	// head-> 11
-	require.NoError(t, f.ProcessBlock(context.Background(), 0, indexToHash(11), indexToHash(9), [32]byte{}, 2, 2))
+	require.NoError(t, f.InsertOptimisticBlock(context.Background(), 0, indexToHash(11), indexToHash(9), 2, 2))
 
 	r, err = f.Head(context.Background(), 2, indexToHash(5), balances, 2)
 	require.NoError(t, err)

beacon-chain/node/BUILD.bazel

@@ -24,6 +24,7 @@ go_library(
         "//beacon-chain/db/slasherkv:go_default_library",
         "//beacon-chain/deterministic-genesis:go_default_library",
         "//beacon-chain/forkchoice:go_default_library",
+        "//beacon-chain/forkchoice/doubly-linked-tree:go_default_library",
         "//beacon-chain/forkchoice/protoarray:go_default_library",
         "//beacon-chain/gateway:go_default_library",
         "//beacon-chain/monitor:go_default_library",