feat(lib/grandpa): Include equivocatory nodes while creating justification

lib/grandpa/grandpa.go

@@ -697,7 +697,7 @@ func (s *Service) determinePreCommit() (*Vote, error) {
 	return &pvb, nil
 }
 
-// isFinalisable returns true is the round is finalisable, false otherwise.
+// isFinalisable returns true if the round is finalisable, false otherwise.
 func (s *Service) isFinalisable(round uint64) (bool, error) {
 	var pvb Vote
 	var err error
@@ -766,16 +766,10 @@ func (s *Service) finalise() error {
 	s.bestFinalCandidate[s.state.round] = bfc
 
 	// create prevote justification ie. list of all signed prevotes for the bfc
-	pvs, err := s.createJustification(bfc.Hash, prevote)
-	if err != nil {
-		return err
-	}
+	pvs := s.createJustification(bfc.Hash, prevote)
 
 	// create precommit justification ie. list of all signed precommits for the bfc
-	pcs, err := s.createJustification(bfc.Hash, precommit)
-	if err != nil {
-		return err
-	}
+	pcs := s.createJustification(bfc.Hash, precommit)
 
 	pcj, err := scale.Marshal(*newJustification(s.state.round, bfc.Hash, bfc.Number, pcs))
 	if err != nil {
@@ -810,43 +804,54 @@ func (s *Service) finalise() error {
 // createJustification collects the signed precommits received for this round and turns them into
 // a justification by adding all signed precommits that are for the best finalised candidate or
 // a descendent of the bfc
-func (s *Service) createJustification(bfc common.Hash, stage Subround) ([]SignedVote, error) {
+func (s *Service) createJustification(bfc common.Hash, stage Subround) []SignedVote {
 	var (
 		spc  *sync.Map
 		err  error
 		just []SignedVote
+		eqv  map[ed25519.PublicKeyBytes][]*SignedVote
 	)
 
 	switch stage {
 	case prevote:
 		spc = s.prevotes
+		eqv = make(map[ed25519.PublicKeyBytes][]*SignedVote, len(s.pvEquivocations))
 	case precommit:
 		spc = s.precommits
+		eqv = make(map[ed25519.PublicKeyBytes][]*SignedVote, len(s.pcEquivocations))
 	}
 
-	// TODO: use equivacatory votes to create justification as well (#1667)
 	spc.Range(func(_, value interface{}) bool {
 		pc := value.(*SignedVote)
 		var isDescendant bool
 
 		isDescendant, err = s.blockState.IsDescendantOf(bfc, pc.Vote.Hash)
 		if err != nil {
 			return false
-		}
-
-		if !isDescendant {
+		} else if !isDescendant {
 			return true
 		}
 
 		just = append(just, *pc)
 		return true
 	})
 
-	if err != nil {
-		return nil, err
+	for _, votes := range eqv {
+		for _, vote := range votes {
+			var signedVote SignedVote = *vote
+			isDescendant, err := s.blockState.IsDescendantOf(bfc, signedVote.Vote.Hash)
+
+			if err != nil {
+				continue
+			} else if !isDescendant {
+				continue
+			}
+
+			just = append(just, signedVote)
+		}
 	}
 
-	return just, nil
+	return just
 }
 
 // derivePrimary returns the primary for the current round

lib/grandpa/message_handler.go

@@ -363,6 +363,7 @@ func (h *MessageHandler) verifyJustification(just *SignedVote, round, setID uint
 
 	// verify authority in justification set
 	authFound := false
+
 	for _, auth := range h.grandpa.authorities() {
 		justKey, err := just.AuthorityID.Encode()
 		if err != nil {

lib/grandpa/vote_message.go

@@ -38,14 +38,14 @@ func (s *Service) receiveMessages(ctx context.Context) {
 	for {
 		select {
 		case msg, ok := <-s.in:
-			if msg == nil || msg.msg == nil {
-				continue
-			}
-
 			if !ok {
 				return
 			}
 
+			if msg == nil || msg.msg == nil {
+				continue
+			}
+
 			logger.Trace("received vote message", "msg", msg.msg, "from", msg.from)
 			vm := msg.msg