Allow initializing assignment to PDOStatement::$queryString

If the object is not created through PDO::prepare(), e.g. in a
mock scenario, it should still be possible to initialize the
$queryString property.

See bug #81084.

Author: nikic

ext/pdo/pdo_stmt.c

@@ -2019,11 +2019,13 @@ PHP_METHOD(PDOStatement, getIterator)
 static zval *dbstmt_prop_write(zend_object *object, zend_string *name, zval *value, void **cache_slot)
 {
 	if (zend_string_equals_literal(name, "queryString")) {
-		zend_throw_error(NULL, "Property queryString is read only");
-		return value;
-	} else {
-		return zend_std_write_property(object, name, value, cache_slot);
+		zval *query_string = OBJ_PROP_NUM(object, 0);
+		if (!Z_ISUNDEF_P(query_string)) {
+			zend_throw_error(NULL, "Property queryString is read only");
+			return value;
+		}
 	}
+	return zend_std_write_property(object, name, value, cache_slot);
 }
 
 static void dbstmt_prop_delete(zend_object *object, zend_string *name, void **cache_slot)

ext/pdo/tests/pdo_036.phpt

@@ -9,6 +9,17 @@ $instance = new reflectionclass('pdostatement');
 $x = $instance->newInstance();
 var_dump($x);
 
+// Allow initializing assignment.
+$x->queryString = "SELECT 1";
+var_dump($x);
+// But don't allow reassignment.
+try {
+    $x->queryString = "SELECT 2";
+    var_dump($x);
+} catch (Error $e) {
+    echo $e->getMessage(), "\n";
+}
+
 $instance = new reflectionclass('pdorow');
 $x = $instance->newInstance();
 var_dump($x);
@@ -19,9 +30,14 @@ object(PDOStatement)#%d (0) {
   ["queryString"]=>
   uninitialized(string)
 }
+object(PDOStatement)#2 (1) {
+  ["queryString"]=>
+  string(8) "SELECT 1"
+}
+Property queryString is read only
 
-Fatal error: Uncaught PDOException: You may not create a PDORow manually in %spdo_036.php:8
+Fatal error: Uncaught PDOException: You may not create a PDORow manually in %spdo_036.php:%d
 Stack trace:
-#0 %spdo_036.php(8): ReflectionClass->newInstance()
+#0 %spdo_036.php(%d): ReflectionClass->newInstance()
 #1 {main}
-  thrown in %spdo_036.php on line 8
+  thrown in %spdo_036.php on line %d