Merge pull request #1902 from CortexFoundation/dev

core: reset tx lookup cache if necessary

core/blockchain.go

@@ -2088,6 +2088,12 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 	} else {
 		log.Error("Impossible reorg, please file an issue", "oldnum", oldBlock.Number(), "oldhash", oldBlock.Hash(), "newnum", newBlock.Number(), "newhash", newBlock.Hash())
 	}
+	// Reset the tx lookup cache in case to clear stale txlookups.
+	// This is done before writing any new chain data to avoid the
+	// weird scenario that canonical chain is changed while the
+	// stale lookups are still cached.
+	bc.txLookupCache.Purge()
+
 	// Insert the new chain(except the head block(reverse order)),
 	// taking care of the proper incremental order.
 	for i := len(newChain) - 1; i >= 1; i-- {
@@ -2102,11 +2108,16 @@ func (bc *BlockChain) reorg(oldBlock, newBlock *types.Block) error {
 
 	// Delete useless indexes right now which includes the non-canonical
 	// transaction indexes, canonical chain indexes which above the head.
-	indexesBatch := bc.db.NewBatch()
-	for _, tx := range types.HashDifference(deletedTxs, addedTxs) {
+	var (
+		indexesBatch = bc.db.NewBatch()
+		diffs        = types.HashDifference(deletedTxs, addedTxs)
+	)
+	for _, tx := range diffs {
 		rawdb.DeleteTxLookupEntry(indexesBatch, tx)
 	}
-	// Delete any canonical number assignments above the new head
+	// Delete all hash markers that are not part of the new canonical chain.
+	// Because the reorg function does not handle new chain head, all hash
+	// markers greater than or equal to new chain head should be deleted.
 	number := commonBlock.NumberU64()
 	if len(newChain) > 1 {
 		number = newChain[1].NumberU64()