Fix reply block edge cases and tests (#4881)

* Covered 2 edge cases and tests

* Consider process epoch

beacon-chain/stategen/BUILD.bazel

@@ -23,11 +23,14 @@ go_test(
     srcs = ["replay_test.go"],
     embed = [":go_default_library"],
     deps = [
+        "//beacon-chain/core/blocks:go_default_library",
         "//beacon-chain/db:go_default_library",
         "//beacon-chain/db/testing:go_default_library",
         "//beacon-chain/state:go_default_library",
         "//proto/beacon/p2p/v1:go_default_library",
         "//shared/bytesutil:go_default_library",
+        "//shared/params:go_default_library",
+        "//shared/testutil:go_default_library",
         "@com_github_prysmaticlabs_ethereumapis//eth/v1alpha1:go_default_library",
         "@com_github_prysmaticlabs_go_ssz//:go_default_library",
     ],

beacon-chain/stategen/replay.go

@@ -15,26 +15,19 @@ import (
 func (s *State) replayBlocks(ctx context.Context, state *state.BeaconState, signed []*ethpb.SignedBeaconBlock, targetSlot uint64) (*state.BeaconState, error) {
 	var err error
 	// The input block list is sorted in decreasing slots order.
-	for i := len(signed) - 1; i >= 0; i-- {
-		// If there is skip slot.
-		for state.Slot() < signed[i].Block.Slot {
-			state, err = transition.ProcessSlot(ctx, state)
+	if len(signed) > 0 {
+		for i := len(signed) - 1; i >= 0; i-- {
+			state, err = transition.ExecuteStateTransitionNoVerifyAttSigs(ctx, state, signed[i])
 			if err != nil {
 				return nil, err
 			}
 		}
-		state, err = transition.ProcessBlockNoVerifyAttSigs(ctx, state, signed[i])
-		if err != nil {
-			return nil, err
-		}
 	}
 
 	// If there is skip slots at the end.
-	for state.Slot() < targetSlot {
-		state, err = transition.ProcessSlot(ctx, state)
-		if err != nil {
-			return nil, err
-		}
+	state, err = transition.ProcessSlots(ctx, state, targetSlot)
+	if err != nil {
+		return nil, err
 	}
 
 	return state, nil

beacon-chain/stategen/replay_test.go

@@ -7,13 +7,88 @@ import (
 
 	ethpb "github.com/prysmaticlabs/ethereumapis/eth/v1alpha1"
 	"github.com/prysmaticlabs/go-ssz"
+	"github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
 	"github.com/prysmaticlabs/prysm/beacon-chain/db"
 	testDB "github.com/prysmaticlabs/prysm/beacon-chain/db/testing"
 	stateTrie "github.com/prysmaticlabs/prysm/beacon-chain/state"
 	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
+	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
 )
 
+func TestReplayBlocks_AllSkipSlots(t *testing.T) {
+	db := testDB.SetupDB(t)
+	defer testDB.TeardownDB(t, db)
+
+	beaconState, _ := testutil.DeterministicGenesisState(t, 32)
+	genesisBlock := blocks.NewGenesisBlock([]byte{})
+	bodyRoot, err := ssz.HashTreeRoot(genesisBlock.Block)
+	if err != nil {
+		t.Fatal(err)
+	}
+	beaconState.SetLatestBlockHeader(&ethpb.BeaconBlockHeader{
+		Slot:       genesisBlock.Block.Slot,
+		ParentRoot: genesisBlock.Block.ParentRoot,
+		StateRoot:  params.BeaconConfig().ZeroHash[:],
+		BodyRoot:   bodyRoot[:],
+	})
+	beaconState.SetSlashings(make([]uint64, params.BeaconConfig().EpochsPerSlashingsVector))
+	cp := beaconState.CurrentJustifiedCheckpoint()
+	mockRoot := [32]byte{}
+	copy(mockRoot[:], "hello-world")
+	cp.Root = mockRoot[:]
+	beaconState.SetCurrentJustifiedCheckpoint(cp)
+	beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{})
+
+	service := New(db)
+	targetSlot := params.BeaconConfig().SlotsPerEpoch - 1
+	newState, err := service.replayBlocks(context.Background(), beaconState, []*ethpb.SignedBeaconBlock{}, targetSlot)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if newState.Slot() != targetSlot {
+		t.Error("Did not advance slots")
+	}
+}
+
+func TestReplayBlocks_SameSlot(t *testing.T) {
+	db := testDB.SetupDB(t)
+	defer testDB.TeardownDB(t, db)
+
+	beaconState, _ := testutil.DeterministicGenesisState(t, 32)
+	genesisBlock := blocks.NewGenesisBlock([]byte{})
+	bodyRoot, err := ssz.HashTreeRoot(genesisBlock.Block)
+	if err != nil {
+		t.Fatal(err)
+	}
+	beaconState.SetLatestBlockHeader(&ethpb.BeaconBlockHeader{
+		Slot:       genesisBlock.Block.Slot,
+		ParentRoot: genesisBlock.Block.ParentRoot,
+		StateRoot:  params.BeaconConfig().ZeroHash[:],
+		BodyRoot:   bodyRoot[:],
+	})
+	beaconState.SetSlashings(make([]uint64, params.BeaconConfig().EpochsPerSlashingsVector))
+	cp := beaconState.CurrentJustifiedCheckpoint()
+	mockRoot := [32]byte{}
+	copy(mockRoot[:], "hello-world")
+	cp.Root = mockRoot[:]
+	beaconState.SetCurrentJustifiedCheckpoint(cp)
+	beaconState.SetCurrentEpochAttestations([]*pb.PendingAttestation{})
+
+	service := New(db)
+	targetSlot := beaconState.Slot()
+	newState, err := service.replayBlocks(context.Background(), beaconState, []*ethpb.SignedBeaconBlock{}, targetSlot)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if newState.Slot() != targetSlot {
+		t.Error("Did not advance slots")
+	}
+}
+
 func TestLoadBlocks_FirstBranch(t *testing.T) {
 	db := testDB.SetupDB(t)
 	defer testDB.TeardownDB(t, db)