prevent instantiation and cloning of __PHP_Incomplete_Class

Author: jordikroon

ext/standard/basic_functions.stub.php

@@ -1487,6 +1487,8 @@
 #[AllowDynamicProperties]
 final class __PHP_Incomplete_Class
 {
+    private function __construct() {}
+    private function __clone(): void {}
 }
 
 class AssertionError extends Error

ext/standard/basic_functions_arginfo.h

@@ -111,6 +111,8 @@ 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;
@@ -122,6 +124,26 @@ PHPAPI void php_register_incomplete_class_handlers(void)
 }
 /* }}} */
 
+/* {{{ Private constructor preventing instantiation */
+static ZEND_COLD zend_function *incomplete_class_get_constructor(zend_object *object) /* {{{ */
+{
+	zend_throw_error(NULL, "Instantiation of class Closure is not allowed");
+	return NULL;
+}
+
+ZEND_COLD ZEND_METHOD(__PHP_Incomplete_Class, __construct)
+{
+	zend_throw_error(NULL, "Instantiation of class __PHP_Incomplete_Class is not allowed");
+}
+/* }}} */
+
+/* {{{ Private clone preventing cloning */
+ZEND_COLD ZEND_METHOD(__PHP_Incomplete_Class, __clone)
+{
+	zend_throw_error(NULL, "Cannot clone __PHP_Incomplete_Class using __clone()");
+}
+/* }}} */
+
 /* {{{ php_lookup_class_name */
 PHPAPI zend_string *php_lookup_class_name(zend_object *object)
 {

ext/standard/basic_functions_decl.h

@@ -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: Call to private method __PHP_Incomplete_Class::__clone() from global scope in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

ext/standard/incomplete_class.c

@@ -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: Call to private __PHP_Incomplete_Class::__construct() from global scope in %s:%d
+Stack trace:
+#0 {main}
+  thrown in %s on line %d

ext/standard/tests/serialize/incomplete_class_clone.phpt

@@ -0,0 +1,12 @@
+--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