fix(state/grandpa): track changes across forks

dot/core/service.go

@@ -22,8 +22,8 @@ import (
 	"github.com/ChainSafe/gossamer/lib/runtime/wasmer"
 	"github.com/ChainSafe/gossamer/lib/services"
 	"github.com/ChainSafe/gossamer/lib/transaction"
-	cscale "github.com/centrifuge/go-substrate-rpc-client/v3/scale"
-	ctypes "github.com/centrifuge/go-substrate-rpc-client/v3/types"
+	cscale "github.com/centrifuge/go-substrate-rpc-client/v4/scale"
+	ctypes "github.com/centrifuge/go-substrate-rpc-client/v4/types"
 )
 
 var (

dot/digest/digest.go

@@ -18,6 +18,10 @@ var (
 	_ services.Service = &Handler{}
 )
 
+var (
+	ErrUnknownConsensusEngineID = errors.New("unknown consensus engine ID")
+)
+
 // Handler is used to handle consensus messages and relevant authority updates to BABE and GRANDPA
 type Handler struct {
 	ctx    context.Context
@@ -32,28 +36,9 @@ type Handler struct {
 	imported  chan *types.Block
 	finalised chan *types.FinalisationInfo
 
-	// GRANDPA changes
-	grandpaScheduledChange *grandpaChange
-	grandpaForcedChange    *grandpaChange
-	grandpaPause           *pause
-	grandpaResume          *resume
-
 	logger log.LeveledLogger
 }
 
-type grandpaChange struct {
-	auths   []types.Authority
-	atBlock uint
-}
-
-type pause struct {
-	atBlock uint
-}
-
-type resume struct {
-	atBlock uint
-}
-
 // NewHandler returns a new Handler
 func NewHandler(lvl log.Level, blockState BlockState, epochState EpochState,
 	grandpaState GrandpaState) (*Handler, error) {
@@ -91,44 +76,80 @@ func (h *Handler) Stop() error {
 	return nil
 }
 
-// NextGrandpaAuthorityChange returns the block number of the next upcoming grandpa authorities change.
-// It returns 0 if no change is scheduled.
-func (h *Handler) NextGrandpaAuthorityChange() (next uint) {
-	next = ^uint(0)
-
-	if h.grandpaScheduledChange != nil {
-		next = h.grandpaScheduledChange.atBlock
+// HandleDigests handles consensus digests for an imported block
+func (h *Handler) HandleDigests(header *types.Header) error {
+	consensusDigests := h.toConsensusDigests(header.Digest.Types)
+	consensusDigests, err := checkForGRANDPAForcedChanges(consensusDigests)
+	if err != nil {
+		return fmt.Errorf("failed while checking GRANDPA digests: %w", err)
 	}
 
-	if h.grandpaForcedChange != nil && h.grandpaForcedChange.atBlock < next {
-		next = h.grandpaForcedChange.atBlock
+	for i := range consensusDigests {
+		// avoiding implicit memory aliasing in for loop, since:
+		// for _, digest := range consensusDigests { &digest }
+		// is using the address of a loop variable
+		digest := consensusDigests[i]
+		err := h.handleConsensusDigest(&digest, header)
+		if err != nil {
+			h.logger.Errorf("cannot handle consensus digest: %w", err)
+		}
 	}
 
-	if h.grandpaPause != nil && h.grandpaPause.atBlock < next {
-		next = h.grandpaPause.atBlock
-	}
+	return nil
+}
+
+// toConsensusDigests converts a slice of scale.VaryingDataType to a slice of types.ConsensusDigest.
+func (h *Handler) toConsensusDigests(scaleVaryingTypes []scale.VaryingDataType) []types.ConsensusDigest {
+	consensusDigests := make([]types.ConsensusDigest, 0, len(scaleVaryingTypes))
+
+	for _, d := range scaleVaryingTypes {
+		digest, ok := d.Value().(types.ConsensusDigest)
+		if !ok {
+			h.logger.Debugf("digest type not supported: %T", d.Value())
+			continue
+		}
 
-	if h.grandpaResume != nil && h.grandpaResume.atBlock < next {
-		next = h.grandpaResume.atBlock
+		switch digest.ConsensusEngineID {
+		case types.GrandpaEngineID, types.BabeEngineID:
+			consensusDigests = append(consensusDigests, digest)
+		}
 	}
 
-	return next
+	return consensusDigests
 }
 
-// HandleDigests handles consensus digests for an imported block
-func (h *Handler) HandleDigests(header *types.Header) {
-	for i, d := range header.Digest.Types {
-		val, ok := d.Value().(types.ConsensusDigest)
-		if !ok {
+// checkForGRANDPAForcedChanges removes any GrandpaScheduledChange in the presence of a
+// GrandpaForcedChange in the same block digest, returning a new slice of types.ConsensusDigest
+func checkForGRANDPAForcedChanges(digests []types.ConsensusDigest) ([]types.ConsensusDigest, error) {
+	var hasForcedChange bool
+	digestsWithoutScheduled := make([]types.ConsensusDigest, 0, len(digests))
+	for _, digest := range digests {
+		if digest.ConsensusEngineID != types.GrandpaEngineID {
+			digestsWithoutScheduled = append(digestsWithoutScheduled, digest)
 			continue
 		}
 
-		err := h.handleConsensusDigest(&val, header)
+		data := types.NewGrandpaConsensusDigest()
+		err := scale.Unmarshal(digest.Data, &data)
 		if err != nil {
-			h.logger.Errorf("cannot handle digest for block number %d, index %d, digest %s: %s",
-				header.Number, i, d.Value(), err)
+			return nil, fmt.Errorf("cannot unmarshal GRANDPA consensus digest: %w", err)
+		}
+
+		switch data.Value().(type) {
+		case types.GrandpaScheduledChange:
+		case types.GrandpaForcedChange:
+			hasForcedChange = true
+			digestsWithoutScheduled = append(digestsWithoutScheduled, digest)
+		default:
+			digestsWithoutScheduled = append(digestsWithoutScheduled, digest)
 		}
 	}
+
+	if hasForcedChange {
+		return digestsWithoutScheduled, nil
+	}
+
+	return digests, nil
 }
 
 func (h *Handler) handleConsensusDigest(d *types.ConsensusDigest, header *types.Header) error {
@@ -139,42 +160,19 @@ func (h *Handler) handleConsensusDigest(d *types.ConsensusDigest, header *types.
 		if err != nil {
 			return err
 		}
-		err = h.handleGrandpaConsensusDigest(data, header)
-		if err != nil {
-			return err
-		}
-		return nil
+
+		return h.grandpaState.HandleGRANDPADigest(header, data)
 	case types.BabeEngineID:
 		data := types.NewBabeConsensusDigest()
 		err := scale.Unmarshal(d.Data, &data)
 		if err != nil {
 			return err
 		}
-		err = h.handleBabeConsensusDigest(data, header)
-		if err != nil {
-			return err
-		}
-		return nil
-	}
-
-	return errors.New("unknown consensus engine ID")
-}
 
-func (h *Handler) handleGrandpaConsensusDigest(digest scale.VaryingDataType, header *types.Header) error {
-	switch val := digest.Value().(type) {
-	case types.GrandpaScheduledChange:
-		return h.handleScheduledChange(val, header)
-	case types.GrandpaForcedChange:
-		return h.handleForcedChange(val, header)
-	case types.GrandpaOnDisabled:
-		return nil // do nothing, as this is not implemented in substrate
-	case types.GrandpaPause:
-		return h.handlePause(val)
-	case types.GrandpaResume:
-		return h.handleResume(val)
+		return h.handleBabeConsensusDigest(data, header)
+	default:
+		return fmt.Errorf("%w: 0x%x", ErrUnknownConsensusEngineID, d.ConsensusEngineID.ToBytes())
 	}
-
-	return errors.New("invalid consensus digest data")
 }
 
 func (h *Handler) handleBabeConsensusDigest(digest scale.VaryingDataType, header *types.Header) error {
@@ -194,7 +192,7 @@ func (h *Handler) handleBabeConsensusDigest(digest scale.VaryingDataType, header
 		return nil
 
 	case types.BABEOnDisabled:
-		return h.handleBABEOnDisabled(val, header)
+		return nil
 
 	case types.NextConfigData:
 		currEpoch, err := h.epochState.GetEpochForBlock(header)
@@ -220,10 +218,14 @@ func (h *Handler) handleBlockImport(ctx context.Context) {
 				continue
 			}
 
-			h.HandleDigests(&block.Header)
-			err := h.handleGrandpaChangesOnImport(block.Header.Number)
+			err := h.HandleDigests(&block.Header)
 			if err != nil {
-				h.logger.Errorf("failed to handle grandpa changes on block import: %s", err)
+				h.logger.Errorf("failed to handle digests: %s", err)
+			}
+
+			err = h.grandpaState.ApplyForcedChanges(&block.Header)
+			if err != nil {
+				h.logger.Errorf("failed to apply forced changes: %s", err)
 			}
 		case <-ctx.Done():
 			return
@@ -249,159 +251,13 @@ func (h *Handler) handleBlockFinalisation(ctx context.Context) {
 				h.logger.Errorf("failed to persist babe next epoch config: %s", err)
 			}
 
-			err = h.handleGrandpaChangesOnFinalization(info.Header.Number)
+			err = h.grandpaState.ApplyScheduledChanges(&info.Header)
 			if err != nil {
-				h.logger.Errorf("failed to handle grandpa changes on block finalisation: %s", err)
+				h.logger.Errorf("failed to apply scheduled change: %s", err)
 			}
+
 		case <-ctx.Done():
 			return
 		}
 	}
 }
-
-func (h *Handler) handleGrandpaChangesOnImport(num uint) error {
-	resume := h.grandpaResume
-	if resume != nil && num >= resume.atBlock {
-		h.grandpaResume = nil
-	}
-
-	fc := h.grandpaForcedChange
-	if fc != nil && num >= fc.atBlock {
-		curr, err := h.grandpaState.IncrementSetID()
-		if err != nil {
-			return err
-		}
-
-		h.grandpaForcedChange = nil
-		h.logger.Debugf("incremented grandpa set id %d", curr)
-	}
-
-	return nil
-}
-
-func (h *Handler) handleGrandpaChangesOnFinalization(num uint) error {
-	pause := h.grandpaPause
-	if pause != nil && num >= pause.atBlock {
-		h.grandpaPause = nil
-	}
-
-	sc := h.grandpaScheduledChange
-	if sc != nil && num >= sc.atBlock {
-		curr, err := h.grandpaState.IncrementSetID()
-		if err != nil {
-			return err
-		}
-
-		h.grandpaScheduledChange = nil
-		h.logger.Debugf("incremented grandpa set id %d", curr)
-	}
-
-	// if blocks get finalised before forced change takes place, disregard it
-	h.grandpaForcedChange = nil
-	return nil
-}
-
-func (h *Handler) handleScheduledChange(sc types.GrandpaScheduledChange, header *types.Header) error {
-	curr, err := h.blockState.BestBlockHeader()
-	if err != nil {
-		return err
-	}
-
-	if h.grandpaScheduledChange != nil {
-		return nil
-	}
-
-	h.logger.Debugf("handling GrandpaScheduledChange data: %v", sc)
-
-	c, err := newGrandpaChange(sc.Auths, sc.Delay, curr.Number)
-	if err != nil {
-		return err
-	}
-
-	h.grandpaScheduledChange = c
-
-	auths, err := types.GrandpaAuthoritiesRawToAuthorities(sc.Auths)
-	if err != nil {
-		return err
-	}
-	h.logger.Debugf("setting GrandpaScheduledChange at block %d",
-		header.Number+uint(sc.Delay))
-	return h.grandpaState.SetNextChange(
-		types.NewGrandpaVotersFromAuthorities(auths),
-		header.Number+uint(sc.Delay),
-	)
-}
-
-func (h *Handler) handleForcedChange(fc types.GrandpaForcedChange, header *types.Header) error {
-	if header == nil {
-		return errors.New("header is nil")
-	}
-
-	if h.grandpaForcedChange != nil {
-		return errors.New("already have forced change scheduled")
-	}
-
-	h.logger.Debugf("handling GrandpaForcedChange with data %v", fc)
-
-	c, err := newGrandpaChange(fc.Auths, fc.Delay, header.Number)
-	if err != nil {
-		return err
-	}
-
-	h.grandpaForcedChange = c
-
-	auths, err := types.GrandpaAuthoritiesRawToAuthorities(fc.Auths)
-	if err != nil {
-		return err
-	}
-
-	h.logger.Debugf("setting GrandpaForcedChange at block %d",
-		header.Number+uint(fc.Delay))
-	return h.grandpaState.SetNextChange(
-		types.NewGrandpaVotersFromAuthorities(auths),
-		header.Number+uint(fc.Delay),
-	)
-}
-
-func (h *Handler) handlePause(p types.GrandpaPause) error {
-	curr, err := h.blockState.BestBlockHeader()
-	if err != nil {
-		return err
-	}
-
-	h.grandpaPause = &pause{
-		atBlock: curr.Number + uint(p.Delay),
-	}
-
-	return h.grandpaState.SetNextPause(h.grandpaPause.atBlock)
-}
-
-func (h *Handler) handleResume(r types.GrandpaResume) error {
-	curr, err := h.blockState.BestBlockHeader()
-	if err != nil {
-		return err
-	}
-
-	h.grandpaResume = &resume{
-		atBlock: curr.Number + uint(r.Delay),
-	}
-
-	return h.grandpaState.SetNextResume(h.grandpaResume.atBlock)
-}
-
-func newGrandpaChange(raw []types.GrandpaAuthoritiesRaw, delay uint32, currBlock uint) (*grandpaChange, error) {
-	auths, err := types.GrandpaAuthoritiesRawToAuthorities(raw)
-	if err != nil {
-		return nil, err
-	}
-
-	return &grandpaChange{
-		auths:   auths,
-		atBlock: currBlock + uint(delay),
-	}, nil
-}
-
-func (h *Handler) handleBABEOnDisabled(_ types.BABEOnDisabled, _ *types.Header) error {
-	h.logger.Debug("handling BABEOnDisabled")
-	return nil
-}