We can modify the bool output of the wp_is_fatal_error_handler_enabled() function in two ways:
Constant
Set the WP_DISABLE_FATAL_ERROR_HANDLER constant to true within the wp-config.php file:
/**
* Disable the fatal error handler.
*/
const WP_DISABLE_FATAL_ERROR_HANDLER = true;
or
define( 'WP_DISABLE_FATAL_ERROR_HANDLER', true );
Filter
Use wp_fatal_error_handler_enabled bool filter:
/**
* Disable the fatal error handler.
*/
add_filter( 'wp_fatal_error_handler_enabled', '__return_false' );
Notes
See ticket #44458
The wp_fatal_error_handler_enabled filter will override the value of the WP_DISABLE_FATAL_ERROR_HANDLER constant.
Also watch out for a possible bool confusion with the constant disabling but the filter enabling.
In my testing the filter approach, as a must-use plugin, is not working as expected, so I’m using the constant instead. Hopefully I can look into this further.
One can also add a custom drop-in file fatal-error-handler.php into the wp-content directory (src), to override the WP_Fatal_Error_Handler class as needed. We must use a different class name and it must define the handle() method as the registered shutdown function.
A simple example to disable it would be to override the default error handler class with a custom one that does nothing:
<?php
class WPSE_Fatal_Error_Handler {
public function handle() {}
}
return new WPSE_Fatal_Error_Handler;
Anonymous class in PHP 7+ seems to work as well:
<?php
return new Class(){
public function handle() {}
};
It could also extend the default WP_Fatal_Error_Handler class if needed.
Then there’s the WP_SANDBOX_SCRAPING constant. See #46045
Setting the WP_DEBUG as true will not disable the WSOD protection. This is by design. See #46825