在 WordPress 的系统盘重新部署后（PHP 7.4 升级至 PHP 8.1），提示：此站点遇到了致命错误。

1、参考：在阿里云的 ECS 中，CentOS 7 迁移（更换）至 Alibaba Cloud Linux 3 。 在 WordPress 的系统盘重新部署后，提示：此站点遇到了致命错误。如图1

图1

2、了解有关对WordPress进行故障排除的更多信息。启用开发者专用：WordPress 调试模式。编辑 wp-config.php

/**
 * 开发者专用：WordPress 调试模式。
 *
 * 将这个值改为“true”，WordPress 将显示所有用于开发的提示。
 * 强烈建议插件开发者在开发环境中启用本功能。
 */
define('WP_DEBUG', true);

3、再次刷新页面，报错

Deprecated: Return type of HM\BackUpWordPress\CleanUpIterator::accept() should either be compatible with FilterIterator::accept(): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /data/wwwroot/www.shuijingwanwq.com/wp-content/plugins/backupwordpress/classes/class-path.php on line 456

Fatal error: Uncaught Error: Undefined constant "wp_cumulus_widget" in /data/wwwroot/www.shuijingwanwq.com/wp-content/plugins/wp-cumulus/wp-cumulus.php:375 Stack trace: #0 /data/wwwroot/www.shuijingwanwq.com/wp-includes/class-wp-hook.php(308): widget_init_wp_cumulus_widget() #1 /data/wwwroot/www.shuijingwanwq.com/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters() #2 /data/wwwroot/www.shuijingwanwq.com/wp-includes/plugin.php(517): WP_Hook->do_action() #3 /data/wwwroot/www.shuijingwanwq.com/wp-includes/widgets.php(1854): do_action() #4 /data/wwwroot/www.shuijingwanwq.com/wp-includes/class-wp-hook.php(308): wp_widgets_init() #5 /data/wwwroot/www.shuijingwanwq.com/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters() #6 /data/wwwroot/www.shuijingwanwq.com/wp-includes/plugin.php(517): WP_Hook->do_action() #7 /data/wwwroot/www.shuijingwanwq.com/wp-settings.php(623): do_action() #8 /data/wwwroot/www.shuijingwanwq.com/wp-config.php(87): require_once('...') #9 /data/wwwroot/www.shuijingwanwq.com/wp-load.php(50): require_once('...') #10 /data/wwwroot/www.shuijingwanwq.com/wp-blog-header.php(13): require_once('...') #11 /data/wwwroot/www.shuijingwanwq.com/index.php(17): require('...') #12 {main} thrown in /data/wwwroot/www.shuijingwanwq.com/wp-content/plugins/wp-cumulus/wp-cumulus.php on line 375

4、发现皆是插件的报错，决定先想办法禁用掉相关报错的插件。由于WordPress仪表盘，则需要以不同的方式禁用插件。参考：如何禁用WordPress插件（4种方法）。

5、参考：如何通过phpMyAdmin禁用WordPress插件 。其本质是操作数据库中的数据。

6、先备份数据库，再操作数据。打开表 wp_options，如图2

图2

7、在选项表中，在 option_name 列中查找 active_plugins 条目。执行以下查询 SQL。如图3

图3

SELECT * FROM `wp_options` WHERE `option_name` = 'active_plugins'

8、复制查询结果记录中的 列 option_value 的值，使用 php 在线反序列化工具。

a:14:{i:0;s:53:"accelerated-mobile-pages/accelerated-moblie-pages.php";i:1;s:19:"akismet/akismet.php";i:2;s:35:"backupwordpress/backupwordpress.php";i:3;s:33:"classic-editor/classic-editor.php";i:4;s:36:"contact-form-7/wp-contact-form-7.php";i:5;s:45:"disable-google-fonts/disable-google-fonts.php";i:6;s:72:"golang-brush-for-syntaxhighlighter-evolved/syntaxhighlighter-GoBrush.php";i:7;s:25:"hueman-addons/ha-fire.php";i:8;s:15:"light/light.php";i:9;s:33:"nimble-builder/nimble-builder.php";i:10;s:47:"regenerate-thumbnails/regenerate-thumbnails.php";i:11;s:39:"syntaxhighlighter/syntaxhighlighter.php";i:12;s:25:"wp-cumulus/wp-cumulus.php";i:13;s:27:"wp-pagenavi/wp-pagenavi.php";}


Array
(
    [0] => accelerated-mobile-pages/accelerated-moblie-pages.php
    [1] => akismet/akismet.php
    [2] => backupwordpress/backupwordpress.php
    [3] => classic-editor/classic-editor.php
    [4] => contact-form-7/wp-contact-form-7.php
    [5] => disable-google-fonts/disable-google-fonts.php
    [6] => golang-brush-for-syntaxhighlighter-evolved/syntaxhighlighter-GoBrush.php
    [7] => hueman-addons/ha-fire.php
    [8] => light/light.php
    [9] => nimble-builder/nimble-builder.php
    [10] => regenerate-thumbnails/regenerate-thumbnails.php
    [11] => syntaxhighlighter/syntaxhighlighter.php
    [12] => wp-cumulus/wp-cumulus.php
    [13] => wp-pagenavi/wp-pagenavi.php
)

9、在反序列化的结果中删除掉插件：backupwordpress/backupwordpress.php、wp-cumulus/wp-cumulus.php，再将 PHP 序列化后的结果存入至列 option_value 的值。PHP 代码实现如下

<?php
$a = 'a:14:{i:0;s:53:"accelerated-mobile-pages/accelerated-moblie-pages.php";i:1;s:19:"akismet/akismet.php";i:2;s:35:"backupwordpress/backupwordpress.php";i:3;s:33:"classic-editor/classic-editor.php";i:4;s:36:"contact-form-7/wp-contact-form-7.php";i:5;s:45:"disable-google-fonts/disable-google-fonts.php";i:6;s:72:"golang-brush-for-syntaxhighlighter-evolved/syntaxhighlighter-GoBrush.php";i:7;s:25:"hueman-addons/ha-fire.php";i:8;s:15:"light/light.php";i:9;s:33:"nimble-builder/nimble-builder.php";i:10;s:47:"regenerate-thumbnails/regenerate-thumbnails.php";i:11;s:39:"syntaxhighlighter/syntaxhighlighter.php";i:12;s:25:"wp-cumulus/wp-cumulus.php";i:13;s:27:"wp-pagenavi/wp-pagenavi.php";}';
$b = unserialize($a);
print_r($b);
$c = [
    'accelerated-mobile-pages/accelerated-moblie-pages.php',
    'akismet/akismet.php',
    'classic-editor/classic-editor.php',
    'contact-form-7/wp-contact-form-7.php',
    'disable-google-fonts/disable-google-fonts.php',
    'golang-brush-for-syntaxhighlighter-evolved/syntaxhighlighter-GoBrush.php',
    'hueman-addons/ha-fire.php',
    'light/light.php',
    'nimble-builder/nimble-builder.php',
    'regenerate-thumbnails/regenerate-thumbnails.php',
    'syntaxhighlighter/syntaxhighlighter.php',
    'wp-pagenavi/wp-pagenavi.php'
];
print_r($c);
$d = serialize($c);
print_r($d);
exit;
?>

Array
(
    [0] => accelerated-mobile-pages/accelerated-moblie-pages.php
    [1] => akismet/akismet.php
    [2] => classic-editor/classic-editor.php
    [3] => contact-form-7/wp-contact-form-7.php
    [4] => disable-google-fonts/disable-google-fonts.php
    [5] => golang-brush-for-syntaxhighlighter-evolved/syntaxhighlighter-GoBrush.php
    [6] => hueman-addons/ha-fire.php
    [7] => light/light.php
    [8] => nimble-builder/nimble-builder.php
    [9] => regenerate-thumbnails/regenerate-thumbnails.php
    [10] => syntaxhighlighter/syntaxhighlighter.php
    [11] => wp-pagenavi/wp-pagenavi.php
)

a:12:{i:0;s:53:"accelerated-mobile-pages/accelerated-moblie-pages.php";i:1;s:19:"akismet/akismet.php";i:2;s:33:"classic-editor/classic-editor.php";i:3;s:36:"contact-form-7/wp-contact-form-7.php";i:4;s:45:"disable-google-fonts/disable-google-fonts.php";i:5;s:72:"golang-brush-for-syntaxhighlighter-evolved/syntaxhighlighter-GoBrush.php";i:6;s:25:"hueman-addons/ha-fire.php";i:7;s:15:"light/light.php";i:8;s:33:"nimble-builder/nimble-builder.php";i:9;s:47:"regenerate-thumbnails/regenerate-thumbnails.php";i:10;s:39:"syntaxhighlighter/syntaxhighlighter.php";i:11;s:27:"wp-pagenavi/wp-pagenavi.php";}

UPDATE `shuijingwanwq`.`wp_options` SET `option_value`='a:12:{i:0;s:53:"accelerated-mobile-pages/accelerated-moblie-pages.php";i:1;s:19:"akismet/akismet.php";i:2;s:33:"classic-editor/classic-editor.php";i:3;s:36:"contact-form-7/wp-contact-form-7.php";i:4;s:45:"disable-google-fonts/disable-google-fonts.php";i:5;s:72:"golang-brush-for-syntaxhighlighter-evolved/syntaxhighlighter-GoBrush.php";i:6;s:25:"hueman-addons/ha-fire.php";i:7;s:15:"light/light.php";i:8;s:33:"nimble-builder/nimble-builder.php";i:9;s:47:"regenerate-thumbnails/regenerate-thumbnails.php";i:10;s:39:"syntaxhighlighter/syntaxhighlighter.php";i:11;s:27:"wp-pagenavi/wp-pagenavi.php";}' WHERE `option_id`=35;

10、还原第 2 步骤的更改后，再次刷新页面，显示正常。