Fixed bug #21957 (serialize() mangles objects with __sleep).

ext/standard/tests/serialize/bug21957.phpt

@@ -0,0 +1,49 @@
+--TEST--
+Bug #21957 (serialize() mangles objects with __sleep)
+--FILE--
+<?php 
+class test
+{
+	var $a, $b;
+
+	function test()
+	{
+		$this->a = 7;
+		$this->b = 2;
+	}
+
+	function __sleep()
+	{
+		$this->b = 0;
+	}
+}
+
+$t['one'] = 'ABC';
+$t['two'] = new test();
+
+var_dump($t);
+
+$s =  @serialize($t);
+echo $s . "\n";
+
+var_dump(unserialize($s));
+?>
+--EXPECT--
+array(2) {
+  ["one"]=>
+  string(3) "ABC"
+  ["two"]=>
+  object(test)#1 (2) {
+    ["a"]=>
+    int(7)
+    ["b"]=>
+    int(2)
+  }
+}
+a:2:{s:3:"one";s:3:"ABC";s:3:"two";N;}
+array(2) {
+  ["one"]=>
+  string(3) "ABC"
+  ["two"]=>
+  NULL
+}

ext/standard/var.c

@@ -483,7 +483,7 @@ static void php_var_serialize_class(smart_str *buf, zval **struc, zval *retval_p
 						"serialize.");
 				/* we should still add element even if it's not OK,
 				   since we already wrote the length of the array before */
-				smart_str_appendl(buf,"s:0:\"\";N;", 9);
+				smart_str_appendl(buf,"N;", 2);
 				continue;
 			}
 
@@ -565,6 +565,9 @@ static void php_var_serialize_intern(smart_str *buf, zval **struc, HashTable *va
 								php_error_docref(NULL TSRMLS_CC, E_NOTICE, "__sleep should return an array only "
 												 "containing the names of instance-variables to "
 												 "serialize.");
+								/* we should still add element even if it's not OK,
+				   				since we already wrote the length of the array before */
+								smart_str_appendl(buf,"N;", 2);
 							}
 							
 							zval_ptr_dtor(&retval_ptr);