do_action( 'wp_error_added', string|int $code, string $message, mixed $data, WP_Error $wp_error )

add_action( 'wp_error_added', function( $code, $message, $data, $wp_error ) {
    // Log all errors
    error_log( sprintf( 'WP_Error: [%s] %s', $code, $message ) );
    
    // Track specific error codes
    if ( $code === 'rest_forbidden' ) {
        do_action( 'my_access_denied_tracking', $message, $data );
    }
}, 10, 4 );

do_action( 'is_wp_error_instance', WP_Error $thing )

add_action( 'is_wp_error_instance', function( $error ) {
    // Debug logging for development
    if ( WP_DEBUG ) {
        error_log( 'WP_Error encountered: ' . $error->get_error_message() );
    }
} );

apply_filters( 'wp_die_handler', callable $callback )

add_filter( 'wp_die_handler', function( $handler ) {
    return function( $message, $title, $args ) use ( $handler ) {
        // Custom logging
        error_log( "wp_die: $message" );
        
        // Custom template for frontend
        if ( ! is_admin() ) {
            include get_template_directory() . '/error.php';
            exit;
        }
        
        // Default for admin
        call_user_func( $handler, $message, $title, $args );
    };
} );

apply_filters( 'wp_die_ajax_handler', callable $callback )

apply_filters( 'wp_die_json_handler', callable $callback )

apply_filters( 'wp_die_jsonp_handler', callable $callback )

apply_filters( 'wp_die_xmlrpc_handler', callable $callback )

apply_filters( 'wp_die_xml_handler', callable $callback )

apply_filters( 'wp_should_handle_php_error', bool $should_handle, array $error )

add_filter( 'wp_should_handle_php_error', function( $should_handle, $error ) {
    // Also handle E_WARNING in production
    if ( $error['type'] === E_WARNING && ! WP_DEBUG ) {
        return true;
    }
    return $should_handle;
}, 10, 2 );

apply_filters( 'wp_fatal_error_handler_enabled', bool $enabled )

$GLOBALS['wp_filter'] = array(
    'wp_fatal_error_handler_enabled' => array(
        10 => array(
            array(
                'accepted_args' => 0,
                'function'      => function() {
                    return false; // Disable handler
                },
            ),
        ),
    ),
);

apply_filters( 'wp_php_error_message', string $message, array $error )

add_filter( 'wp_php_error_message', function( $message, $error ) {
    // Add contact info
    $message .= '<p>Contact support: [email protected]</p>';
    
    // Add error details in debug mode
    if ( WP_DEBUG_DISPLAY ) {
        $message .= sprintf(
            '<pre>%s in %s on line %d</pre>',
            esc_html( $error['message'] ),
            esc_html( $error['file'] ),
            $error['line']
        );
    }
    
    return $message;
}, 10, 2 );

apply_filters( 'wp_php_error_args', array $args, array $error )

array(
    'response' => 500,
    'exit'     => false,
)

add_filter( 'wp_php_error_args', function( $args, $error ) {
    // Add a link to status page
    $args['link_url']  = 'https://status.example.com';
    $args['link_text'] = 'Check system status';
    
    return $args;
}, 10, 2 );

// In test setup
add_filter( 'wp_die_handler', function() {
    return function( $message, $title, $args ) {
        throw new WPDieException( $message );
    };
} );

// In test
$this->expectException( WPDieException::class );
wp_die( 'Test error' );