backport to 5.6 (we should not unset the default value)

Author: laruence

NEWS

@@ -3,6 +3,8 @@ PHP                                                                        NEWS
 ?? ??? 2016, PHP 5.6.25
 
 - Core:
+  . Fixed bug #72581 (previous property undefined in Exception after
+    deserialization). (Laruence)
   . Fixed bug #72024 (microtime() leaks memory). (maroszek at gmx dot net)
 
 - Curl:

Zend/zend_exceptions.c

@@ -230,7 +230,7 @@ ZEND_METHOD(exception, __construct)
    Exception unserialize checks */
 #define CHECK_EXC_TYPE(name, type) \
 	value = zend_read_property(default_exception_ce, object, name, sizeof(name)-1, 0 TSRMLS_CC); \
-	if(value && Z_TYPE_P(value) != type) { \
+	if (value && Z_TYPE_P(value) != IS_NULL && Z_TYPE_P(value) != type) { \
 		zval *tmp; \
 		MAKE_STD_ZVAL(tmp); \
 		ZVAL_STRINGL(tmp, name, sizeof(name)-1, 1); \

ext/standard/tests/serialize/bug69152.phpt

@@ -9,7 +9,6 @@ $x->test();
 
 ?>
 --EXPECTF--
-Notice: Undefined property: Exception::$previous in %s on line %d
 exception 'Exception' in %s:%d
 Stack trace:
 #0 {main}

ext/standard/tests/serialize/bug69793.phpt

@@ -7,8 +7,6 @@ $e = unserialize('O:9:"Exception":7:{s:17:"'."\0".'Exception'."\0".'string";s:1:
 var_dump($e."");
 ?>
 --EXPECTF--
-Notice: Undefined property: Exception::$message in %s%ebug69793.php on line %d
-
 Notice: Undefined property: Exception::$file in %s%ebug69793.php on line %d
 
 Notice: Undefined property: Exception::$previous in %s%ebug69793.php on line %d