# __PHP_Incomplete_Class 类

(PHP 4 >=4.0.1, PHP 5, PHP 7, PHP 8)

## 简介

由 unserialize() 创建的在尝试反序列化未定义类或未在 unserialize() 的 `options` 数组的 `allowed_classes` 中列出的类。

在 PHP 7.2.0 之前，对 __PHP_Incomplete_Class 类使用 is_object() 会返回 `false`。从 PHP 7.2.0 开始，将返回 `true`。

## 类摘要

#[\AllowDynamicProperties]
final class __PHP_Incomplete_Class {
}

此类没有默认属性或方法。 由 unserialize() 创建时， 除了所有反序列化的属性和值之外， 对象还将具有一个 `__PHP_Incomplete_Class_Name` 属性， 该属性将包含反序列化类的名称。

## 更新日志

版本 | 说明
--- | ---
8.0.0 | 此类现在是 `final`。

## 示例

示例 #1 由 unserialize() 创建

    <?php

    class MyClass
    {
        public string $property = "myValue";
    }

    $myObject = new MyClass;

    $foo = serialize($myObject);

    // unserializes all objects into __PHP_Incomplete_Class objects
    $disallowed = unserialize($foo, ["allowed_classes" => false]);

    var_dump($disallowed);

    // unserializes all objects into __PHP_Incomplete_Class objects except those of MyClass2 and MyClass3
    $disallowed2 = unserialize($foo, ["allowed_classes" => ["MyClass2", "MyClass3"]]);

    var_dump($disallowed2);

    // unserializes undefined class into __PHP_Incomplete_Class object
    $undefinedClass = unserialize('O:16:"MyUndefinedClass":0:{}');

    var_dump($undefinedClass);

以上示例会输出：

    object(__PHP_Incomplete_Class)#2 (2) {
      ["__PHP_Incomplete_Class_Name"]=>
      string(7) "MyClass"
      ["property"]=>
      string(7) "myValue"
    }
    object(__PHP_Incomplete_Class)#3 (2) {
      ["__PHP_Incomplete_Class_Name"]=>
      string(7) "MyClass"
      ["property"]=>
      string(7) "myValue"
    }
    object(__PHP_Incomplete_Class)#4 (1) {
      ["__PHP_Incomplete_Class_Name"]=>
      string(16) "MyUndefinedClass"
    }

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