core: reset tx lookup cache if necessary (#28865) (#1157)

This pull request resets the txlookup cache if chain reorg happens, 
preventing them from remaining reachable. It addresses failures in
the hive tests.

Co-authored-by: rjl493456442 <[email protected]>

core/blockchain.go

@@ -2682,6 +2682,12 @@ func (bc *BlockChain) reorg(oldHead *types.Header, newHead *types.Block) error {
 
 		log.Error("Impossible reorg, please file an issue", "oldnum", oldBlock.Number(), "oldhash", oldBlock.Hash(), "oldblocks", len(oldChain), "newnum", newBlock.Number(), "newhash", newBlock.Hash(), "newblocks", len(newChain))
 	}
+	// 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-- {
@@ -2696,11 +2702,13 @@ func (bc *BlockChain) reorg(oldHead *types.Header, newHead *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 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.