Prevent instantiation and cloning of __PHP_Incomplete_Class

ext/standard/basic_functions.stub.php

@@ -1487,6 +1487,7 @@
 #[AllowDynamicProperties]
 final class __PHP_Incomplete_Class
 {
+    private function __construct() {}
 }
 
 class AssertionError extends Error

ext/standard/incomplete_class.c

@@ -95,6 +95,21 @@ static zend_function *incomplete_class_get_method(zend_object **object, zend_str
 }
 /* }}} */
 
+/* {{{ Private constructor preventing instantiation */
+static ZEND_COLD zend_function *incomplete_class_get_constructor(zend_object *object) /* {{{ */
+{
+	zend_throw_error(NULL, "Instantiation of class __PHP_Incomplete_Class is not allowed");
+	return NULL;
+}
+
+ZEND_COLD ZEND_METHOD(__PHP_Incomplete_Class, __construct)
+{
+	ZEND_PARSE_PARAMETERS_NONE();
+
+	zend_throw_error(NULL, "Instantiation of class __PHP_Incomplete_Class is not allowed");
+}
+/* }}} */
+
 /* {{{ php_create_incomplete_class */
 static zend_object *php_create_incomplete_object(zend_class_entry *class_type)
 {
@@ -111,12 +126,15 @@ static zend_object *php_create_incomplete_object(zend_class_entry *class_type)
 PHPAPI void php_register_incomplete_class_handlers(void)
 {
 	memcpy(&php_incomplete_object_handlers, &std_object_handlers, sizeof(zend_object_handlers));
+
+	php_incomplete_object_handlers.get_constructor = incomplete_class_get_constructor;
 	php_incomplete_object_handlers.read_property = incomplete_class_get_property;
 	php_incomplete_object_handlers.has_property = incomplete_class_has_property;
 	php_incomplete_object_handlers.unset_property = incomplete_class_unset_property;
 	php_incomplete_object_handlers.write_property = incomplete_class_write_property;
 	php_incomplete_object_handlers.get_property_ptr_ptr = incomplete_class_get_property_ptr_ptr;
 	php_incomplete_object_handlers.get_method = incomplete_class_get_method;
+	php_incomplete_object_handlers.clone_obj = NULL;
 
 	php_ce_incomplete_class->create_object = php_create_incomplete_object;
 }

ext/standard/tests/serialize/incomplete_class.phpt

@@ -3,7 +3,8 @@
 --FILE--
 <?php
 
-$d = serialize(new __PHP_Incomplete_Class);
+$orig = unserialize('O:7:"Unknown":0:{}');
+$d = serialize($orig);
 $o = unserialize($d);
 var_dump($o);
 
@@ -18,13 +19,15 @@ var_dump($o->test2);
 echo "Done\n";
 ?>
 --EXPECTF--
-object(__PHP_Incomplete_Class)#%d (0) {
+object(__PHP_Incomplete_Class)#%d (1) {
+  ["__PHP_Incomplete_Class_Name"]=>
+  string(7) "Unknown"
 }
-The script tried to modify a property on an incomplete object. Please ensure that the class definition "unknown" of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide an autoloader to load the class definition
+The script tried to modify a property on an incomplete object. Please ensure that the class definition "Unknown" of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide an autoloader to load the class definition
 
-Warning: main(): The script tried to access a property on an incomplete object. Please ensure that the class definition "unknown" of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide an autoloader to load the class definition in %s on line %d
+Warning: main(): The script tried to access a property on an incomplete object. Please ensure that the class definition "Unknown" of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide an autoloader to load the class definition in %s on line %d
 NULL
 
-Warning: main(): The script tried to access a property on an incomplete object. Please ensure that the class definition "unknown" of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide an autoloader to load the class definition in %s on line %d
+Warning: main(): The script tried to access a property on an incomplete object. Please ensure that the class definition "Unknown" of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide an autoloader to load the class definition in %s on line %d
 NULL
 Done

ext/standard/tests/serialize/incomplete_class_clone.phpt

@@ -0,0 +1,19 @@
+--TEST--
+__PHP_Incomplete_Class cannot be cloned
+--FILE--
+<?php
+$o = unserialize('O:3:"Foo":0:{}');
+var_dump($o::class);
+
+$rc = new ReflectionClass("__PHP_Incomplete_Class");
+var_dump($rc->isCloneable());
+var_dump(clone($o));
+?>
+--EXPECTF--
+string(22) "__PHP_Incomplete_Class"
+bool(false)
+
+Fatal error: Uncaught Error: Trying to clone an uncloneable object of class __PHP_Incomplete_Class in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

ext/standard/tests/serialize/incomplete_class_constructor.phpt

@@ -0,0 +1,14 @@
+--TEST--
+__PHP_Incomplete_Class cannot be instantiated
+--FILE--
+<?php
+var_dump(__PHP_Incomplete_Class::class);
+var_dump(new __PHP_Incomplete_Class());
+?>
+--EXPECTF--
+string(22) "__PHP_Incomplete_Class"
+
+Fatal error: Uncaught Error: Instantiation of class __PHP_Incomplete_Class is not allowed in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

ext/standard/tests/serialize/incomplete_class_newinstancewithoutconstructor.phpt

@@ -0,0 +1,13 @@
+--TEST--
+ReflectionClass::newInstanceWithoutConstructor cannot instantiate __PHP_Incomplete_Class
+--FILE--
+<?php
+$rc = new ReflectionClass("__PHP_Incomplete_Class");
+$rc->newInstanceWithoutConstructor();
+?>
+--EXPECTF--
+Fatal error: Uncaught ReflectionException: Class __PHP_Incomplete_Class is an internal class marked as final that cannot be instantiated without invoking its constructor in %s:%d
+Stack trace:
+#0 %s(%d): ReflectionClass->newInstanceWithoutConstructor()
+#1 {main}
+  thrown in %s on line %d

ext/standard/tests/serialize/serialization_objects_006.phpt

@@ -2,16 +2,18 @@
 Behaviour of incomplete class is preserved even when it was not created by unserialize().
 --FILE--
 <?php
-$a = new __PHP_Incomplete_Class;
+$a = unserialize('O:7:"Unknown":0:{}');
 var_dump($a);
 var_dump($a->p);
 
 echo "Done";
 ?>
 --EXPECTF--
-object(__PHP_Incomplete_Class)#%d (0) {
+object(__PHP_Incomplete_Class)#1 (1) {
+  ["__PHP_Incomplete_Class_Name"]=>
+  string(7) "Unknown"
 }
 
-Warning: main(): The script tried to access a property on an incomplete object. Please ensure that the class definition "unknown" of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide an autoloader to load the class definition in %s on line %d
+Warning: main(): The script tried to access a property on an incomplete object. Please ensure that the class definition "Unknown" of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide an autoloader to load the class definition in %s on line %d
 NULL
 Done