Use time.Time instead of uint64 for genesis time (#15419)

* Convert genesis times from seconds to time.Time

* Fixing failed forkchoice tests in a new commit so it doesn't get worse

Fixing failed spectest tests in a new commit so it doesn't get worse

Fixing forkchoice tests, then spectests

* Fixing forkchoice tests, then spectests. Now asking for help...

* Fix TestForkChoice_GetProposerHead

* Fix broken build

* Resolve TODO(preston) items

* Changelog fragment

* Resolve TODO(preston) items again

* Resolve lint issues

* Use consistant field names for sinceSlotStart (no spaces)

* Manu's feedback

* Renamed StartTime -> UnsafeStartTime, marked as deprecated because it doesn't handle overflow scenarios.
Renamed SlotTime -> StartTime
Renamed SlotAt -> At
Handled the error in cases where StartTime was used.

@james-prysm feedback

* Revert beacon-chain/blockchain/receive_block_test.go from 1b7844de

* Fixing issues after rebase

* Accepted suggestions from @potuz

* Remove CanonicalHeadSlot from merge conflicts

---------

Co-authored-by: potuz <potuz@prysmaticlabs.com>

beacon-chain/state/interfaces.go

@@ -6,6 +6,7 @@ package state
 import (
 	"context"
 	"encoding/json"
+	"time"
 
 	customtypes "github.com/OffchainLabs/prysm/v6/beacon-chain/state/state-native/custom-types"
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
@@ -64,7 +65,7 @@ type ReadOnlyBeaconState interface {
 	ReadOnlyProposerLookahead
 	ToProtoUnsafe() interface{}
 	ToProto() interface{}
-	GenesisTime() uint64
+	GenesisTime() time.Time
 	GenesisValidatorsRoot() []byte
 	Slot() primitives.Slot
 	Fork() *ethpb.Fork
@@ -97,7 +98,7 @@ type WriteOnlyBeaconState interface {
 	WriteOnlyWithdrawals
 	WriteOnlyDeposits
 	WriteOnlyProposerLookahead
-	SetGenesisTime(val uint64) error
+	SetGenesisTime(val time.Time) error
 	SetGenesisValidatorsRoot(val []byte) error
 	SetSlot(val primitives.Slot) error
 	SetFork(val *ethpb.Fork) error

beacon-chain/state/state-native/beacon_state.go

@@ -16,6 +16,11 @@ import (
 
 // BeaconState defines a struct containing utilities for the Ethereum Beacon Chain state, defining
 // getters and setters for its respective values and helpful functions such as HashTreeRoot().
+//
+// Note: genesisTime is time.Time.Unix(). i.e. the number of seconds elapsed since January 1, 1970 UTC.
+// This is preferred over time.Time in the state to avoid unnecessary conversions and precision issues
+// that may break spec compliance. Other areas of Prysm should use time.Time, except when complying
+// with spec.
 type BeaconState struct {
 	version                             int
 	genesisTime                         uint64

beacon-chain/state/state-native/getters_misc.go

@@ -1,6 +1,8 @@
 package state_native
 
 import (
+	"time"
+
 	"github.com/OffchainLabs/prysm/v6/consensus-types/primitives"
 	ethpb "github.com/OffchainLabs/prysm/v6/proto/prysm/v1alpha1"
 	"github.com/OffchainLabs/prysm/v6/runtime/version"
@@ -11,12 +13,12 @@ func (b *BeaconState) Id() uint64 {
 	return b.id
 }
 
-// GenesisTime of the beacon state as a uint64.
-func (b *BeaconState) GenesisTime() uint64 {
+// GenesisTime of the beacon state as a time.Time.
+func (b *BeaconState) GenesisTime() time.Time {
 	b.lock.RLock()
 	defer b.lock.RUnlock()
 
-	return b.genesisTime
+	return time.Unix(int64(b.genesisTime), 0)
 }
 
 // GenesisValidatorsRoot of the beacon state.

beacon-chain/state/state-native/hasher_test.go

@@ -2,6 +2,7 @@ package state_native_test
 
 import (
 	"testing"
+	"time"
 
 	statenative "github.com/OffchainLabs/prysm/v6/beacon-chain/state/state-native"
 	"github.com/OffchainLabs/prysm/v6/config/params"
@@ -18,7 +19,7 @@ import (
 func TestComputeFieldRootsWithHasher_Phase0(t *testing.T) {
 	beaconState, err := util.NewBeaconState(util.FillRootsNaturalOpt)
 	require.NoError(t, err)
-	require.NoError(t, beaconState.SetGenesisTime(123))
+	require.NoError(t, beaconState.SetGenesisTime(time.Unix(123, 0)))
 	require.NoError(t, beaconState.SetGenesisValidatorsRoot(genesisValidatorsRoot()))
 	require.NoError(t, beaconState.SetSlot(123))
 	require.NoError(t, beaconState.SetFork(fork()))
@@ -82,7 +83,7 @@ func TestComputeFieldRootsWithHasher_Phase0(t *testing.T) {
 func TestComputeFieldRootsWithHasher_Altair(t *testing.T) {
 	beaconState, err := util.NewBeaconStateAltair(util.FillRootsNaturalOptAltair)
 	require.NoError(t, err)
-	require.NoError(t, beaconState.SetGenesisTime(123))
+	require.NoError(t, beaconState.SetGenesisTime(time.Unix(123, 0)))
 	require.NoError(t, beaconState.SetGenesisValidatorsRoot(genesisValidatorsRoot()))
 	require.NoError(t, beaconState.SetSlot(123))
 	require.NoError(t, beaconState.SetFork(fork()))
@@ -152,7 +153,7 @@ func TestComputeFieldRootsWithHasher_Altair(t *testing.T) {
 func TestComputeFieldRootsWithHasher_Bellatrix(t *testing.T) {
 	beaconState, err := util.NewBeaconStateBellatrix(util.FillRootsNaturalOptBellatrix)
 	require.NoError(t, err)
-	require.NoError(t, beaconState.SetGenesisTime(123))
+	require.NoError(t, beaconState.SetGenesisTime(time.Unix(123, 0)))
 	require.NoError(t, beaconState.SetGenesisValidatorsRoot(genesisValidatorsRoot()))
 	require.NoError(t, beaconState.SetSlot(123))
 	require.NoError(t, beaconState.SetFork(fork()))
@@ -226,7 +227,7 @@ func TestComputeFieldRootsWithHasher_Bellatrix(t *testing.T) {
 func TestComputeFieldRootsWithHasher_Capella(t *testing.T) {
 	beaconState, err := util.NewBeaconStateCapella(util.FillRootsNaturalOptCapella)
 	require.NoError(t, err)
-	require.NoError(t, beaconState.SetGenesisTime(123))
+	require.NoError(t, beaconState.SetGenesisTime(time.Unix(123, 0)))
 	require.NoError(t, beaconState.SetGenesisValidatorsRoot(genesisValidatorsRoot()))
 	require.NoError(t, beaconState.SetSlot(123))
 	require.NoError(t, beaconState.SetFork(fork()))

beacon-chain/state/state-native/setters_misc.go

@@ -1,6 +1,8 @@
 package state_native
 
 import (
+	"time"
+
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state/state-native/types"
 	"github.com/OffchainLabs/prysm/v6/beacon-chain/state/stateutil"
 	fieldparams "github.com/OffchainLabs/prysm/v6/config/fieldparams"
@@ -43,11 +45,11 @@ const (
 )
 
 // SetGenesisTime for the beacon state.
-func (b *BeaconState) SetGenesisTime(val uint64) error {
+func (b *BeaconState) SetGenesisTime(val time.Time) error {
 	b.lock.Lock()
 	defer b.lock.Unlock()
 
-	b.genesisTime = val
+	b.genesisTime = uint64(val.Unix())
 	b.markFieldAsDirty(types.GenesisTime)
 	return nil
 }