Merge pull request #402 from SiaFoundation/chris/not-on-best-chain-fix

fix sending genesis blocks to peers in syncLoop

Author: n8mgr

.changeset/fix_edge_case_where_a_node_incorrectly_sends_the_genesis_state_to_peers_while_syncing.md

@@ -0,0 +1,5 @@
+---
+default: patch
+---
+
+# Fix edge case where a node incorrectly sends the genesis state to peers while syncing.

syncer/syncer.go

@@ -680,6 +680,11 @@ func (s *Syncer) syncLoop(ctx context.Context) error {
 			go func(p *Peer) {
 				cs, headers, remaining, err := func() (consensus.State, []types.BlockHeader, uint64, error) {
 					for _, id := range hist {
+						if id == (types.BlockID{}) {
+							// skip empty history entries which can occur when
+							// we don't have a full history of blocks.
+							continue
+						}
 						cs, ok := s.cm.State(id)
 						if !ok {
 							return consensus.State{}, nil, 0, errors.New("missing state for history")