升级PHP至7.2后访问页面出现log组件配置异常求助

Let's break down what's happening here and walk through how to fix this issue.

Root Cause #

This error almost always comes down to a mismatch between your Yii framework version and the component configuration syntax you’re using:

• Yii 1.x requires components to define their class with the __class key
• Yii 2.x uses the simpler class key instead

Since you upgraded PHP to 7.2, deleted your old composer.lock/vendor folder, and ran a fresh composer install, it’s likely one of two scenarios:

1. Your composer.json pulled in a different Yii version than you expected (e.g., Yii 1.x instead of Yii 2.x)
2. You’re using Yii 1.x but your log configuration follows Yii 2.x syntax

Solutions #

Case 1: You intended to use Yii 2.x #

1. Validate your Yii version constraint
   Open your composer.json and make sure it specifies a valid Yii 2.x version that supports PHP 7.2 (Yii 2.0.15+ works with PHP 7.2). A typical constraint looks like:

   "require": {
       "yiisoft/yii2": "~2.0.0"
   }
   

   Run composer update to ensure you’re pulling the correct compatible version.

2. Clear runtime cache
   Yii 2 caches configuration files by default. Delete all files in your runtime/cache directory to force the app to load your updated configuration.

3. Confirm no conflicting config overrides
   Your existing log configuration is valid for Yii 2.x, but double-check that no other config files (like config/web-local.php or environment-specific files) are overriding the log component settings.

Case 2: You’re using Yii 1.x #

Yii 1.x uses a different structure for log components. Update your configuration to match Yii 1.x syntax:

$config = [
    // code
    'preload' => ['log'], // Replace Yii 2.x's 'bootstrap' with this for Yii 1.x
    'components' => [
        'errorHandler' => [
            'errorAction' => 'site/error',
        ],
        'log' => [
            '__class' => 'CLogRouter', // Required __class key for Yii 1.x
            'routes' => [ // Yii 1.x uses 'routes' instead of 'targets'
                [
                    '__class' => 'CFileLogRoute',
                    'levels' => 'error, warning',
                ],
            ],
        ]
    ]
    // code
];

Also, ensure you’re using Yii 1.1.26 or later—this is the first Yii 1.x version that supports PHP 7.2. Run composer update to get the latest compatible release if needed.

Quick Additional Checks #

• Verify all PHP 7.2 modules you enabled are compatible with your Yii version (e.g., php7.2-mbstring, php7.2-pdo are mandatory for Yii 2.x)
• Double-check that you fully deleted the old composer.lock file and vendor folder before running composer install—leftover files can cause dependency conflicts

内容的提问来源于stack exchange，提问作者Gothic Prince