Merge pull request #5209 from planetscale/sa-5204

Fixed Panic for handlePrepare in Prepared statements

go/vt/vtgate/executor.go

@@ -1573,9 +1573,9 @@ func (e *Executor) handlePrepare(ctx context.Context, safeSession *SafeSession,
 	if err != nil {
 		logStats.Error = err
 		errCount = 1
-	} else {
-		logStats.RowsAffected = qr.RowsAffected
+		return nil, err
 	}
+	logStats.RowsAffected = qr.RowsAffected
 
 	plan.AddStats(1, time.Since(logStats.StartTime), uint64(logStats.ShardQueries), logStats.RowsAffected, errCount)
 

test/prepared_statement_test.py

@@ -255,6 +255,16 @@ class TestPreparedStatements(unittest.TestCase):
     cursor.fetchone()
     cursor.close()
 
+    # Send an invalid table name to ensure that python's mysql client will not fail before entering vtgate
+    cursor = conn.cursor(cursor_class=MySQLCursorPrepared)
+    try:
+      cursor.execute('select * from prepare_stmt_test where id = %s', (1,))
+    except mysql.connector.Error as err:
+      if err.errno == 1105:
+        print "Could not find the table"
+      else:
+        raise
+
     cursor = conn.cursor(cursor_class=MySQLCursorPrepared)
     cursor.execute('select * from vt_prepare_stmt_test where id = %s', (1,))
     result = cursor.fetchall()