fix(dot/state): actually prune finalized tries from memory

dot/network/service.go

@@ -430,6 +430,25 @@ func (s *Service) sentBlockIntervalTelemetry() {
 func (s *Service) handleConn(conn libp2pnetwork.Conn) {
 	// TODO: currently we only have one set so setID is 0, change this once we have more set in peerSet.
 	s.host.cm.peerSetHandler.Incoming(0, conn.RemotePeer())
+
+	// exchange BlockAnnounceHandshake with peer so we can start to
+	// sync if necessary.
+	prtl, has := s.notificationsProtocols[BlockAnnounceMsgType]
+	if !has {
+		return
+	}
+
+	hs, err := prtl.getHandshake()
+	if err != nil {
+		return
+	}
+
+	stream, err := s.sendHandshake(conn.RemotePeer(), hs, prtl)
+	if err != nil {
+		return
+	}
+
+	_ = stream.Close()
 }
 
 // Stop closes running instances of the host and network services as well as

dot/state/block_finalisation.go

@@ -235,8 +235,17 @@ func (bs *BlockState) handleFinalisedBlock(curr common.Hash) error {
 			return err
 		}
 
-		// the block will be deleted from the unfinalisedBlockMap in the pruning loop
-		// in `SetFinalisedHash()`, which calls this function
+		// delete from the unfinalisedBlockMap and delete reference to in-memory trie
+		block, has = bs.getAndDeleteUnfinalisedBlock(hash)
+		if !has {
+			continue
+		}
+
+		logger.Tracef("cleaned out finalised block from memory; block number %s with hash %s", block.Header.Number, hash)
+
+		go func(header *types.Header) {
+			bs.pruneKeyCh <- header
+		}(&block.Header)
 	}
 
 	return batch.Flush()

dot/state/storage.go

@@ -84,6 +84,7 @@ func (s *StorageState) SetSyncing(syncing bool) {
 }
 
 func (s *StorageState) pruneKey(keyHeader *types.Header) {
+	logger.Tracef("pruning trie, number=%d hash=%s", keyHeader.Number, keyHeader.Hash())
 	s.tries.Delete(keyHeader.StateRoot)
 }
 

lib/blocktree/blocktree.go

@@ -133,20 +133,20 @@ func (bt *BlockTree) getNode(h Hash) (ret *node) {
 // Prune sets the given hash as the new blocktree root,
 // removing all nodes that are not the new root node or its descendant
 // It returns an array of hashes that have been pruned
-func (bt *BlockTree) Prune(finalised Hash) (pruned []Hash) {
+func (bt *BlockTree) Prune(finalised Hash) []Hash {
 	bt.Lock()
 	defer bt.Unlock()
 
 	if finalised == bt.root.hash {
-		return pruned
+		return []Hash{}
 	}
 
 	n := bt.getNode(finalised)
 	if n == nil {
-		return pruned
+		return []Hash{}
 	}
 
-	pruned = bt.root.prune(n, nil)
+	pruned := bt.root.prune(n, nil)
 	bt.root = n
 	bt.root.parent = nil