Fix memory realted to #64726

ext/mysqli/tests/bug64726.phpt

@@ -0,0 +1,23 @@
+--TEST--
+Bug #63398 (Memleak when calling fetch_object on a use_result and DB pointer has closed)
+--SKIPIF--
+<?php
+require_once('skipif.inc');
+require_once("connect.inc");
+if (!$IS_MYSQLND) {
+    die("skip mysqlnd only test");
+}
+require_once('skipifconnectfailure.inc');
+?>
+--FILE--
+<?php
+require 'connect.inc';
+$db = new my_mysqli($host, $user, $passwd, $db, $port, $socket);
+
+$result = $db->query('SELECT 1', MYSQLI_USE_RESULT);
+$db->close();
+var_dump($result->fetch_array());
+?>
+--EXPECTF--
+Warning: mysqli_result::fetch_array(): Error while reading a row in %sbug64726.php on line %d
+bool(false)

ext/mysqlnd/mysqlnd_result.c

@@ -1547,6 +1547,7 @@ MYSQLND_METHOD(mysqlnd_res, fetch_into)(MYSQLND_RES * result, unsigned int flags
 	mysqlnd_array_init(return_value, mysqlnd_num_fields(result) * 2);
 	if (FAIL == result->m.fetch_row(result, (void *)return_value, flags, &fetched_anything TSRMLS_CC)) {
 		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Error while reading a row");
+		zval_dtor(return_value);
 		RETVAL_FALSE;
 	} else if (fetched_anything == FALSE) {
 		zval_dtor(return_value);