Harden beacon state interface for Altair (#8673)

* State: clean up

* Add error to return signature

* Remove SetCurrentEpochAttestations and SetPreviousEpochAttestations

* Fix tests

Co-authored-by: Raul Jordan <raul@prysmaticlabs.com>

beacon-chain/blockchain/metrics_test.go

@@ -25,7 +25,7 @@ func TestReportEpochMetrics_BadAttestation(t *testing.T) {
 	require.NoError(t, err)
 	h, err := testutil.NewBeaconState()
 	require.NoError(t, err)
-	require.NoError(t, h.SetCurrentEpochAttestations([]*pb.PendingAttestation{{InclusionDelay: 0}}))
+	require.NoError(t, h.AppendCurrentEpochAttestations(&pb.PendingAttestation{InclusionDelay: 0}))
 	err = reportEpochMetrics(context.Background(), s, h)
 	require.ErrorContains(t, "attestation with inclusion delay of 0", err)
 }
@@ -36,7 +36,7 @@ func TestReportEpochMetrics_SlashedValidatorOutOfBound(t *testing.T) {
 	require.NoError(t, err)
 	v.Slashed = true
 	require.NoError(t, h.UpdateValidatorAtIndex(0, v))
-	require.NoError(t, h.SetCurrentEpochAttestations([]*pb.PendingAttestation{{InclusionDelay: 1, Data: testutil.HydrateAttestationData(&eth.AttestationData{})}}))
+	require.NoError(t, h.AppendCurrentEpochAttestations(&pb.PendingAttestation{InclusionDelay: 1, Data: testutil.HydrateAttestationData(&eth.AttestationData{})}))
 	err = reportEpochMetrics(context.Background(), h, h)
 	require.ErrorContains(t, "slot 0 out of bounds", err)
 }

beacon-chain/core/blocks/attestation_regression_test.go

@@ -73,7 +73,7 @@ func TestVerifyAttestationNoVerifySignature_IncorrectSourceEpoch(t *testing.T) {
 	ckp := beaconState.CurrentJustifiedCheckpoint()
 	copy(ckp.Root, "hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(ckp))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 
 	err = blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
 	assert.NotEqual(t, nil, err)

beacon-chain/core/blocks/attestation_test.go

@@ -68,7 +68,7 @@ func TestProcessAttestations_NeitherCurrentNorPrevEpoch(t *testing.T) {
 	pfc := beaconState.PreviousJustifiedCheckpoint()
 	pfc.Root = []byte("hello-world")
 	require.NoError(t, beaconState.SetPreviousJustifiedCheckpoint(pfc))
-	require.NoError(t, beaconState.SetPreviousEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendPreviousEpochAttestations(&pb.PendingAttestation{}))
 
 	want := fmt.Sprintf(
 		"expected target epoch (%d) to be the previous epoch (%d) or the current epoch (%d)",
@@ -101,7 +101,7 @@ func TestProcessAttestations_CurrentEpochFFGDataMismatches(t *testing.T) {
 	cfc := beaconState.CurrentJustifiedCheckpoint()
 	cfc.Root = []byte("hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 
 	want := "source check point not equal to current justified checkpoint"
 	_, err := blocks.ProcessAttestations(context.Background(), beaconState, b)
@@ -139,7 +139,7 @@ func TestProcessAttestations_PrevEpochFFGDataMismatches(t *testing.T) {
 	pfc := beaconState.PreviousJustifiedCheckpoint()
 	pfc.Root = []byte("hello-world")
 	require.NoError(t, beaconState.SetPreviousJustifiedCheckpoint(pfc))
-	require.NoError(t, beaconState.SetPreviousEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendPreviousEpochAttestations(&pb.PendingAttestation{}))
 
 	want := "source check point not equal to previous justified checkpoint"
 	_, err = blocks.ProcessAttestations(context.Background(), beaconState, b)
@@ -175,7 +175,7 @@ func TestProcessAttestations_InvalidAggregationBitsLength(t *testing.T) {
 	cfc := beaconState.CurrentJustifiedCheckpoint()
 	cfc.Root = []byte("hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 
 	expected := "failed to verify aggregation bitfield: wanted participants bitfield length 3, got: 4"
 	_, err = blocks.ProcessAttestations(context.Background(), beaconState, b)
@@ -200,7 +200,7 @@ func TestProcessAttestations_OK(t *testing.T) {
 	cfc := beaconState.CurrentJustifiedCheckpoint()
 	cfc.Root = mockRoot[:]
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 
 	committee, err := helpers.BeaconCommitteeFromState(beaconState, att.Data.Slot, att.Data.CommitteeIndex)
 	require.NoError(t, err)
@@ -242,7 +242,7 @@ func TestProcessAggregatedAttestation_OverlappingBits(t *testing.T) {
 	cfc := beaconState.CurrentJustifiedCheckpoint()
 	cfc.Root = bytesutil.PadTo([]byte("hello-world"), 32)
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 
 	committee, err := helpers.BeaconCommitteeFromState(beaconState, att1.Data.Slot, att1.Data.CommitteeIndex)
 	require.NoError(t, err)
@@ -305,7 +305,7 @@ func TestProcessAggregatedAttestation_NoOverlappingBits(t *testing.T) {
 	cfc := beaconState.CurrentJustifiedCheckpoint()
 	cfc.Root = mockRoot[:]
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cfc))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 
 	committee, err := helpers.BeaconCommitteeFromState(beaconState, att1.Data.Slot, att1.Data.CommitteeIndex)
 	require.NoError(t, err)
@@ -395,7 +395,7 @@ func TestProcessAttestationsNoVerify_OK(t *testing.T) {
 	ckp := beaconState.CurrentJustifiedCheckpoint()
 	copy(ckp.Root, "hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(ckp))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 
 	_, err = blocks.ProcessAttestationNoVerifySignature(context.TODO(), beaconState, att)
 	assert.NoError(t, err)
@@ -426,7 +426,7 @@ func TestVerifyAttestationNoVerifySignature_OK(t *testing.T) {
 	ckp := beaconState.CurrentJustifiedCheckpoint()
 	copy(ckp.Root, "hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(ckp))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 
 	err = blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
 	assert.NoError(t, err)
@@ -452,7 +452,7 @@ func TestVerifyAttestationNoVerifySignature_BadAttIdx(t *testing.T) {
 	ckp := beaconState.CurrentJustifiedCheckpoint()
 	copy(ckp.Root, "hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(ckp))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 	err := blocks.VerifyAttestationNoVerifySignature(context.TODO(), beaconState, att)
 	require.ErrorContains(t, "committee index 100 >= committee count 1", err)
 }

beacon-chain/core/epoch/epoch_processing_test.go

@@ -296,7 +296,9 @@ func TestProcessFinalUpdates_CanProcess(t *testing.T) {
 
 	// Verify historical root accumulator was appended.
 	assert.Equal(t, 1, len(newS.HistoricalRoots()), "Unexpected slashed balance")
-	assert.NotNil(t, newS.CurrentEpochAttestations(), "Nil value stored in current epoch attestations instead of empty slice")
+	currAtt, err := newS.CurrentEpochAttestations()
+	require.NoError(t, err)
+	assert.NotNil(t, currAtt, "Nil value stored in current epoch attestations instead of empty slice")
 }
 
 func TestProcessRegistryUpdates_NoRotation(t *testing.T) {

beacon-chain/core/epoch/precompute/attestation.go

@@ -29,7 +29,15 @@ func ProcessAttestations(
 	v := &Validator{}
 	var err error
 
-	for _, a := range append(state.PreviousEpochAttestations(), state.CurrentEpochAttestations()...) {
+	prevAtt, err := state.PreviousEpochAttestations()
+	if err != nil {
+		return nil, nil, err
+	}
+	curAtt, err := state.CurrentEpochAttestations()
+	if err != nil {
+		return nil, nil, err
+	}
+	for _, a := range append(prevAtt, curAtt...) {
 		if a.InclusionDelay == 0 {
 			return nil, nil, errors.New("attestation with inclusion delay of 0")
 		}

beacon-chain/core/epoch/precompute/attestation_test.go

@@ -170,9 +170,9 @@ func TestProcessAttestations(t *testing.T) {
 	require.NoError(t, beaconState.SetBlockRoots(br))
 	att2.Data.Target.Root = newRt[:]
 	att2.Data.BeaconBlockRoot = newRt[:]
-	err := beaconState.SetPreviousEpochAttestations([]*pb.PendingAttestation{{Data: att1.Data, AggregationBits: bf, InclusionDelay: 1}})
+	err := beaconState.AppendPreviousEpochAttestations(&pb.PendingAttestation{Data: att1.Data, AggregationBits: bf, InclusionDelay: 1})
 	require.NoError(t, err)
-	err = beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{{Data: att2.Data, AggregationBits: bf, InclusionDelay: 1}})
+	err = beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{Data: att2.Data, AggregationBits: bf, InclusionDelay: 1})
 	require.NoError(t, err)
 
 	pVals := make([]*precompute.Validator, validators)

beacon-chain/core/state/state_test.go

@@ -73,8 +73,12 @@ func TestGenesisBeaconState_OK(t *testing.T) {
 
 	// Recent state checks.
 	assert.DeepEqual(t, make([]uint64, params.BeaconConfig().EpochsPerSlashingsVector), newState.Slashings(), "Slashings was not correctly initialized")
-	assert.DeepSSZEqual(t, []*pb.PendingAttestation{}, newState.CurrentEpochAttestations(), "CurrentEpochAttestations was not correctly initialized")
-	assert.DeepSSZEqual(t, []*pb.PendingAttestation{}, newState.PreviousEpochAttestations(), "PreviousEpochAttestations was not correctly initialized")
+	currAtt, err := newState.CurrentEpochAttestations()
+	require.NoError(t, err)
+	assert.DeepSSZEqual(t, []*pb.PendingAttestation{}, currAtt, "CurrentEpochAttestations was not correctly initialized")
+	prevAtt, err := newState.CurrentEpochAttestations()
+	require.NoError(t, err)
+	assert.DeepSSZEqual(t, []*pb.PendingAttestation{}, prevAtt, "PreviousEpochAttestations was not correctly initialized")
 
 	zeroHash := params.BeaconConfig().ZeroHash[:]
 	// History root checks.

beacon-chain/core/state/transition_test.go

@@ -293,7 +293,7 @@ func TestProcessBlock_IncorrectProcessExits(t *testing.T) {
 	cp := beaconState.CurrentJustifiedCheckpoint()
 	cp.Root = []byte("hello-world")
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cp))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 	_, err = state.VerifyOperationLengths(context.Background(), beaconState, block)
 	wanted := "number of voluntary exits (17) in block body exceeds allowed threshold of 16"
 	assert.ErrorContains(t, wanted, err)
@@ -319,7 +319,7 @@ func createFullBlockWithOperations(t *testing.T) (iface.BeaconState,
 	copy(mockRoot[:], "hello-world")
 	cp.Root = mockRoot[:]
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cp))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 
 	proposerSlashIdx := types.ValidatorIndex(3)
 	slotsPerEpoch := params.BeaconConfig().SlotsPerEpoch

beacon-chain/rpc/beacon/validators_test.go

@@ -1516,8 +1516,8 @@ func TestServer_GetValidatorParticipation_CurrentAndPrevEpoch(t *testing.T) {
 	require.NoError(t, headState.SetSlot(2*params.BeaconConfig().SlotsPerEpoch-1))
 	require.NoError(t, headState.SetValidators(validators))
 	require.NoError(t, headState.SetBalances(balances))
-	require.NoError(t, headState.SetCurrentEpochAttestations(atts))
-	require.NoError(t, headState.SetPreviousEpochAttestations(atts))
+	require.NoError(t, headState.AppendCurrentEpochAttestations(atts[0]))
+	require.NoError(t, headState.AppendPreviousEpochAttestations(atts[0]))
 
 	b := testutil.NewBeaconBlock()
 	b.Block.Slot = 16
@@ -1595,8 +1595,8 @@ func TestServer_GetValidatorParticipation_OrphanedUntilGenesis(t *testing.T) {
 	require.NoError(t, headState.SetSlot(2*params.BeaconConfig().SlotsPerEpoch-1))
 	require.NoError(t, headState.SetValidators(validators))
 	require.NoError(t, headState.SetBalances(balances))
-	require.NoError(t, headState.SetCurrentEpochAttestations(atts))
-	require.NoError(t, headState.SetPreviousEpochAttestations(atts))
+	require.NoError(t, headState.AppendCurrentEpochAttestations(atts[0]))
+	require.NoError(t, headState.AppendPreviousEpochAttestations(atts[0]))
 
 	b := testutil.NewBeaconBlock()
 	require.NoError(t, beaconDB.SaveBlock(ctx, b))
@@ -1675,8 +1675,8 @@ func TestGetValidatorPerformance_OK(t *testing.T) {
 			AggregationBits: bitfield.Bitlist{},
 			InclusionDelay:  1,
 		}
+		require.NoError(t, headState.AppendPreviousEpochAttestations(atts[i]))
 	}
-	require.NoError(t, headState.SetPreviousEpochAttestations(atts))
 	defaultBal := params.BeaconConfig().MaxEffectiveBalance
 	extraBal := params.BeaconConfig().MaxEffectiveBalance + params.BeaconConfig().GweiPerEth
 	balances := []uint64{defaultBal, extraBal, extraBal + params.BeaconConfig().GweiPerEth}
@@ -2032,12 +2032,12 @@ func TestServer_GetIndividualVotes_Working(t *testing.T) {
 	require.NoError(t, beaconState.SetBlockRoots(br))
 	att2.Data.Target.Root = rt[:]
 	att2.Data.BeaconBlockRoot = newRt[:]
-	err = beaconState.SetPreviousEpochAttestations([]*pb.PendingAttestation{
-		{Data: att1.Data, AggregationBits: bf, InclusionDelay: 1},
+	err = beaconState.AppendPreviousEpochAttestations(&pb.PendingAttestation{
+		Data: att1.Data, AggregationBits: bf, InclusionDelay: 1,
 	})
 	require.NoError(t, err)
-	err = beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{
-		{Data: att2.Data, AggregationBits: bf, InclusionDelay: 1},
+	err = beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{
+		Data: att2.Data, AggregationBits: bf, InclusionDelay: 1,
 	})
 	require.NoError(t, err)
 

beacon-chain/state/interface/phase0.go

@@ -134,8 +134,8 @@ type ReadOnlyEth1Data interface {
 
 // ReadOnlyAttestations defines a struct which only has read access to attestations methods.
 type ReadOnlyAttestations interface {
-	PreviousEpochAttestations() []*pbp2p.PendingAttestation
-	CurrentEpochAttestations() []*pbp2p.PendingAttestation
+	PreviousEpochAttestations() ([]*pbp2p.PendingAttestation, error)
+	CurrentEpochAttestations() ([]*pbp2p.PendingAttestation, error)
 }
 
 // WriteOnlyBlockRoots defines a struct which only has write access to block roots methods.
@@ -189,8 +189,6 @@ type WriteOnlyCheckpoint interface {
 
 // WriteOnlyAttestations defines a struct which only has write access to attestations methods.
 type WriteOnlyAttestations interface {
-	SetPreviousEpochAttestations(val []*pbp2p.PendingAttestation) error
-	SetCurrentEpochAttestations(val []*pbp2p.PendingAttestation) error
 	AppendCurrentEpochAttestations(val *pbp2p.PendingAttestation) error
 	AppendPreviousEpochAttestations(val *pbp2p.PendingAttestation) error
 	RotateAttestations() error

beacon-chain/state/stateV0/getters.go

@@ -781,18 +781,18 @@ func (b *BeaconState) slashings() []uint64 {
 }
 
 // PreviousEpochAttestations corresponding to blocks on the beacon chain.
-func (b *BeaconState) PreviousEpochAttestations() []*pbp2p.PendingAttestation {
+func (b *BeaconState) PreviousEpochAttestations() ([]*pbp2p.PendingAttestation, error) {
 	if !b.hasInnerState() {
-		return nil
+		return nil, nil
 	}
 	if b.state.PreviousEpochAttestations == nil {
-		return nil
+		return nil, nil
 	}
 
 	b.lock.RLock()
 	defer b.lock.RUnlock()
 
-	return b.previousEpochAttestations()
+	return b.previousEpochAttestations(), nil
 }
 
 // previousEpochAttestations corresponding to blocks on the beacon chain.
@@ -806,18 +806,18 @@ func (b *BeaconState) previousEpochAttestations() []*pbp2p.PendingAttestation {
 }
 
 // CurrentEpochAttestations corresponding to blocks on the beacon chain.
-func (b *BeaconState) CurrentEpochAttestations() []*pbp2p.PendingAttestation {
+func (b *BeaconState) CurrentEpochAttestations() ([]*pbp2p.PendingAttestation, error) {
 	if !b.hasInnerState() {
-		return nil
+		return nil, nil
 	}
 	if b.state.CurrentEpochAttestations == nil {
-		return nil
+		return nil, nil
 	}
 
 	b.lock.RLock()
 	defer b.lock.RUnlock()
 
-	return b.currentEpochAttestations()
+	return b.currentEpochAttestations(), nil
 }
 
 // currentEpochAttestations corresponding to blocks on the beacon chain.

beacon-chain/state/stateV0/getters_test.go

@@ -69,8 +69,10 @@ func TestNilState_NoPanic(t *testing.T) {
 	_ = err
 	_ = st.RandaoMixesLength()
 	_ = st.Slashings()
-	_ = st.PreviousEpochAttestations()
-	_ = st.CurrentEpochAttestations()
+	_, err = st.PreviousEpochAttestations()
+	require.NoError(t, err)
+	_, err = st.CurrentEpochAttestations()
+	require.NoError(t, err)
 	_ = st.JustificationBits()
 	_ = st.PreviousJustifiedCheckpoint()
 	_ = st.CurrentJustifiedCheckpoint()

beacon-chain/state/stateV0/references_test.go

@@ -191,10 +191,14 @@ func TestStateReferenceCopy_NoUnexpectedAttestationsMutation(t *testing.T) {
 		{AggregationBits: bitfield.NewBitlist(1)},
 		{AggregationBits: bitfield.NewBitlist(2)},
 	}
-	require.NoError(t, a.SetPreviousEpochAttestations(atts[:1]))
-	require.NoError(t, a.SetCurrentEpochAttestations(atts[:1]))
-	assert.Equal(t, 1, len(a.CurrentEpochAttestations()), "Unexpected number of attestations")
-	assert.Equal(t, 1, len(a.PreviousEpochAttestations()), "Unexpected number of attestations")
+	a.setPreviousEpochAttestations(atts[:1])
+	a.setCurrentEpochAttestations(atts[:1])
+	curAtt, err := a.CurrentEpochAttestations()
+	require.NoError(t, err)
+	assert.Equal(t, 1, len(curAtt), "Unexpected number of attestations")
+	preAtt, err := a.PreviousEpochAttestations()
+	require.NoError(t, err)
+	assert.Equal(t, 1, len(preAtt), "Unexpected number of attestations")
 
 	// Copy, increases reference count.
 	copied := a.Copy()
@@ -226,8 +230,12 @@ func TestStateReferenceCopy_NoUnexpectedAttestationsMutation(t *testing.T) {
 	// Extends state a attestations.
 	require.NoError(t, a.AppendCurrentEpochAttestations(atts[1]))
 	require.NoError(t, a.AppendPreviousEpochAttestations(atts[1]))
-	assert.Equal(t, 2, len(a.CurrentEpochAttestations()), "Unexpected number of attestations")
-	assert.Equal(t, 2, len(a.PreviousEpochAttestations()), "Unexpected number of attestations")
+	curAtt, err = a.CurrentEpochAttestations()
+	require.NoError(t, err)
+	assert.Equal(t, 2, len(curAtt), "Unexpected number of attestations")
+	preAtt, err = a.PreviousEpochAttestations()
+	require.NoError(t, err)
+	assert.Equal(t, 2, len(preAtt), "Unexpected number of attestations")
 	assertAttFound(a.state.GetCurrentEpochAttestations(), 1)
 	assertAttFound(a.state.GetPreviousEpochAttestations(), 1)
 	assertAttFound(a.state.GetCurrentEpochAttestations(), 2)

beacon-chain/state/stateV0/setters.go

@@ -496,19 +496,6 @@ func (b *BeaconState) UpdateSlashingsAtIndex(idx, val uint64) error {
 	return nil
 }
 
-// SetPreviousEpochAttestations for the beacon state. Updates the entire
-// list to a new value by overwriting the previous one.
-func (b *BeaconState) SetPreviousEpochAttestations(val []*pbp2p.PendingAttestation) error {
-	if !b.hasInnerState() {
-		return ErrNilInnerState
-	}
-	b.lock.Lock()
-	defer b.lock.Unlock()
-
-	b.setPreviousEpochAttestations(val)
-	return nil
-}
-
 func (b *BeaconState) setPreviousEpochAttestations(val []*pbp2p.PendingAttestation) {
 	b.sharedFieldReferences[previousEpochAttestations].MinusRef()
 	b.sharedFieldReferences[previousEpochAttestations] = stateutil.NewRef(1)
@@ -518,19 +505,6 @@ func (b *BeaconState) setPreviousEpochAttestations(val []*pbp2p.PendingAttestati
 	b.rebuildTrie[previousEpochAttestations] = true
 }
 
-// SetCurrentEpochAttestations for the beacon state. Updates the entire
-// list to a new value by overwriting the previous one.
-func (b *BeaconState) SetCurrentEpochAttestations(val []*pbp2p.PendingAttestation) error {
-	if !b.hasInnerState() {
-		return ErrNilInnerState
-	}
-	b.lock.Lock()
-	defer b.lock.Unlock()
-
-	b.setCurrentEpochAttestations(val)
-	return nil
-}
-
 func (b *BeaconState) setCurrentEpochAttestations(val []*pbp2p.PendingAttestation) {
 	b.sharedFieldReferences[currentEpochAttestations].MinusRef()
 	b.sharedFieldReferences[currentEpochAttestations] = stateutil.NewRef(1)

beacon-chain/state/stateV0/setters_test.go

@@ -18,6 +18,6 @@ func TestBeaconState_RotateAttestations(t *testing.T) {
 	require.NoError(t, err)
 
 	require.NoError(t, st.RotateAttestations())
-	require.Equal(t, 0, len(st.CurrentEpochAttestations()))
-	require.Equal(t, types.Slot(456), st.PreviousEpochAttestations()[0].Data.Slot)
+	require.Equal(t, 0, len(st.currentEpochAttestations()))
+	require.Equal(t, types.Slot(456), st.previousEpochAttestations()[0].Data.Slot)
 }

beacon-chain/state/stategen/replay_test.go

@@ -38,7 +38,7 @@ func TestReplayBlocks_AllSkipSlots(t *testing.T) {
 	copy(mockRoot[:], "hello-world")
 	cp.Root = mockRoot[:]
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cp))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 
 	service := New(beaconDB)
 	targetSlot := params.BeaconConfig().SlotsPerEpoch - 1
@@ -67,7 +67,7 @@ func TestReplayBlocks_SameSlot(t *testing.T) {
 	copy(mockRoot[:], "hello-world")
 	cp.Root = mockRoot[:]
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cp))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 
 	service := New(beaconDB)
 	targetSlot := beaconState.Slot()
@@ -97,7 +97,7 @@ func TestReplayBlocks_LowerSlotBlock(t *testing.T) {
 	copy(mockRoot[:], "hello-world")
 	cp.Root = mockRoot[:]
 	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(cp))
-	require.NoError(t, beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{}))
+	require.NoError(t, beaconState.AppendCurrentEpochAttestations(&pb.PendingAttestation{}))
 
 	service := New(beaconDB)
 	targetSlot := beaconState.Slot()

shared/testutil/block_test.go

@@ -119,7 +119,9 @@ func TestGenerateFullBlock_ValidAttestations(t *testing.T) {
 	require.NoError(t, err)
 	beaconState, err = state.ExecuteStateTransition(context.Background(), beaconState, block)
 	require.NoError(t, err)
-	if len(beaconState.CurrentEpochAttestations()) != 4 {
+	atts, err := beaconState.CurrentEpochAttestations()
+	require.NoError(t, err)
+	if len(atts) != 4 {
 		t.Fatal("expected 4 attestations to be saved to the beacon state")
 	}
 }