BUG22564149: Fix cmd_query_iter() when using bytestrings with Python 2

Executing cmd_query_iter() raises an exception when using bytestrings
statements with Python 2.

This patch verifies if the statements are already bytestrings before
attempting to encode them.

A test was added for regression.

Author: nmariz

lib/mysql/connector/connection.py

@@ -29,7 +29,7 @@
 import time
 
 from .authentication import get_auth_plugin
-from .catch23 import PY2, isstr
+from .catch23 import PY2, isstr, UNICODE_TYPES
 from .constants import (
     ClientFlag, ServerCmd, ServerFlag,
     flag_is_set, ShutdownType, NET_BUFFER_LENGTH
@@ -517,10 +517,9 @@ def cmd_query_iter(self, statements):
         Returns a generator.
         """
         if not isinstance(statements, bytearray):
-            if isstr(statements):
-                statements = bytearray(statements.encode('utf-8'))
-            else:
-                statements = bytearray(statements)
+            if isstr(statements) and isinstance(statements, UNICODE_TYPES):
+                statements = statements.encode('utf8')
+            statements = bytearray(statements)
 
         # Handle the first query result
         yield self._handle_result(self._send_cmd(ServerCmd.QUERY, statements))

tests/test_bugs.py

@@ -4433,3 +4433,30 @@ def test_parse_mysql_config(self):
         self.assertEqual(2, len(info["include"]))
         self.assertEqual(includes[0], info["include"][0])
         self.assertEqual(includes[1], info["include"][1])
+
+
+class BugOra22564149(tests.MySQLConnectorTests):
+    """BUG#22564149: CMD_QUERY_ITER ERRONEOUSLY CALLS ".ENCODE('UTF8')" ON
+    BYTESTRINGS
+    """
+    def setUp(self):
+        config = tests.get_mysql_config()
+        self.tbl = "BugOra22564149"
+        self.cnx = connection.MySQLConnection(**config)
+        self.cnx.cmd_query("DROP TABLE IF EXISTS {0}".format(self.tbl))
+        self.cnx.cmd_query("CREATE TABLE {0} (id INT, name VARCHAR(50))"
+                           "".format(self.tbl))
+
+    def tearDown(self):
+        self.cnx.cmd_query("DROP TABLE IF EXISTS {0}".format(self.tbl))
+        self.cnx.close()
+
+    def test_cmd_query_iter(self):
+        stmt = (u"SELECT 1; INSERT INTO {0} VALUES (1, 'João'),(2, 'André'); "
+                u"SELECT 3")
+        results = []
+        for result in self.cnx.cmd_query_iter(
+                stmt.format(self.tbl).encode("utf-8")):
+            results.append(result)
+            if "columns" in result:
+                results.append(self.cnx.get_rows())