WP_CONTENT_DIR in wp_register_fatal_error_handler

[sebastian.pisula]

I think this is a problem. My case:

I created file fatal-error-handler.php in wp-content directory. In the file I put the code:

<?php

class IC_Fatal_Error_Handler extends WP_Fatal_Error_Handler {
        public function handle() {
                wp_die( 'error' );
        }
}

return new IC_Fatal_Error_Handler();

And nothing. The file isn't loaded. I think that wp_register_fatal_error_handler() should be call after calling wp_initial_constants()

[TimothyBlynJacobs]

Also reported here: https://core.trac.wordpress.org/ticket/46047#comment:9

[diddledani]

The conditional check in wp-includes/error-protection.php will always fail so the drop-in file will never be loaded. It checks for defined( 'WP_CONTENT_DIR' ) which will always be false unless the site owner has explicitly set it in wp-config.php. This is because the default definition of this constant is later in the lifecycle.

[SergeyBiryukov]

In 45056:

Bootstrap/Load: Ensure the fatal error handler is registered after WP_CONTENT_DIR is defined, so the custom error handler drop-in could be properly loaded.

Props sebastian.pisula, diddledan.
Fixes #46069.