如何通过WordPress调试解决错误？演示站点严重错误调试指南

Alright, let's tackle that WordPress critical error you're seeing on your demo site, and walk through how to debug WordPress issues in general. Here's a step-by-step guide that's tried and true for developers:

The first thing you need to do is turn on WordPress's built-in debugging tools—this will replace that vague "critical error" message with specific details about what's breaking your site.

To do this, edit your site's wp-config.php file (it's located in your WordPress root directory, accessible via FTP, cPanel File Manager, or your local server's file explorer). Look for the line that says define( 'WP_DEBUG', false ); and replace it with these lines:

// Enable debug mode
define( 'WP_DEBUG', true );
// Log errors to a file instead of showing them on the front end
define( 'WP_DEBUG_LOG', true );
// Hide errors from site visitors (good for demo/production sites)
define( 'WP_DEBUG_DISPLAY', false );
// Turn off PHP's default error display
@ini_set( 'display_errors', 0 );

If you don't see the WP_DEBUG line, just add those lines right above the comment that says /* That's all, stop editing! Happy publishing. */.

Once debugging is enabled, WordPress will log all errors to a file called debug.log in the wp-content folder. Open this file, and you'll see specific messages like:

Fatal error: Uncaught Error: Call to undefined function example_function() in /wp-content/plugins/bad-plugin/plugin-file.php:42

This tells you exactly which file (and line number) is causing the problem—whether it's a faulty plugin, broken theme code, or a core file issue.

Now that you have error details, narrow down the issue with these common fixes:

• Disable all plugins: Rename your wp-content/plugins folder to plugins-old via FTP. If your site starts working again, rename the folder back to plugins and re-enable each plugin one by one until the error reappears—you've found the culprit.
• Switch to a default theme: Rename your active theme's folder (in wp-content/themes) to something like broken-theme—WordPress will automatically switch to a default theme like Twenty Twenty-Four. If the error goes away, your custom theme has a bug.
• Roll back recent changes: If you just updated a plugin, theme, or WordPress core, revert that update. For plugins/themes, you can download an older version from their repository and replace the files via FTP.
• Check file permissions: Make sure WordPress folders have permissions set to 755 and files to 644—incorrect permissions can cause critical errors, especially on hosted demo sites.
• Increase PHP memory limit: Sometimes errors happen because WordPress doesn't have enough memory. Add this line to your wp-config.php (above the "happy publishing" comment):

  define( 'WP_MEMORY_LIMIT', '256M' );
  

For future issues, follow this repeatable process:

1. Enable debug mode to get specific error details.
2. Check the debug.log to pinpoint the problematic file/code.
3. Isolate the issue by testing plugins, themes, and recent changes.
4. Fix the error (update the faulty plugin/theme, repair broken code, or replace corrupted core files).
5. Once the site is working, disable debug mode by setting WP_DEBUG back to false (you don't want debug logs cluttering your site or showing sensitive info to visitors).

内容的提问来源于stack exchange，提问作者Omnia Magd