core/rawdb: better log messages for ancient failure (ethereum#21327)

Author: rjl493456442

core/rawdb/database.go

@@ -137,7 +137,10 @@ func NewDatabaseWithFreezer(db ethdb.KeyValueStore, freezer string, namespace st
 			// If the freezer already contains something, ensure that the genesis blocks
 			// match, otherwise we might mix up freezers across chains and destroy both
 			// the freezer and the key-value store.
-			if frgenesis, _ := frdb.Ancient(freezerHashTable, 0); !bytes.Equal(kvgenesis, frgenesis) {
+			frgenesis, err := frdb.Ancient(freezerHashTable, 0)
+			if err != nil {
+				return nil, fmt.Errorf("failed to retrieve genesis from ancient %v", err)
+			} else if !bytes.Equal(kvgenesis, frgenesis) {
 				return nil, fmt.Errorf("genesis mismatch: %#x (leveldb) != %#x (ancients)", kvgenesis, frgenesis)
 			}
 			// Key-value store and freezer belong to the same network. Ensure that they