wp_debug_mode() │ WP 3.0.0

Set PHP error reporting based on WordPress debug settings.

Uses three constants: WP_DEBUG, WP_DEBUG_DISPLAY, and WP_DEBUG_LOG. All three can be defined in wp-config.php. By default, WP_DEBUG and WP_DEBUG_LOG are set to false, and WP_DEBUG_DISPLAY is set to true.

When WP_DEBUG is true, all PHP notices are reported. WordPress will also display internal notices: when a deprecated WordPress function, function argument, or file is used. Deprecated code may be removed from a later version.

It is strongly recommended that plugin and theme developers use WP_DEBUG in their development environments.

WP_DEBUG_DISPLAY and WP_DEBUG_LOG perform no function unless WP_DEBUG is true.

When WP_DEBUG_DISPLAY is true, WordPress will force errors to be displayed. WP_DEBUG_DISPLAY defaults to true. Defining it as null prevents WordPress from changing the global configuration setting. Defining WP_DEBUG_DISPLAY as false will force errors to be hidden.

When WP_DEBUG_LOG is true, errors will be logged to wp-content/debug.log. When WP_DEBUG_LOG is a valid path, errors will be logged to the specified file.

Errors are never displayed for XML-RPC, REST, ms-files.php, and Ajax requests.

Internal function — this function is designed to be used by the kernel itself. It is not recommended to use this function in your code.

Hooks from the function

Return

null. Nothing (null).

Usage

wp_debug_mode();

Examples

0

#1 There are no examples.

This function is used by the kernel for error management and is not intended to be used in development.

Changelog

Since 3.0.0 Introduced.
Since 5.1.0 WP_DEBUG_LOG can be a file path.

wp_debug_mode() code WP 6.8

wp-includes/load.php 
function wp_debug_mode() {
	/**
	 * Filters whether to allow the debug mode check to occur.
	 *
	 * This filter runs before it can be used by plugins. It is designed for
	 * non-web runtimes. Returning false causes the `WP_DEBUG` and related
	 * constants to not be checked and the default PHP values for errors
	 * will be used unless you take care to update them yourself.
	 *
	 * To use this filter you must define a `$wp_filter` global before
	 * WordPress loads, usually in `wp-config.php`.
	 *
	 * Example:
	 *
	 *     $GLOBALS['wp_filter'] = array(
	 *         'enable_wp_debug_mode_checks' => array(
	 *             10 => array(
	 *                 array(
	 *                     'accepted_args' => 0,
	 *                     'function'      => function() {
	 *                         return false;
	 *                     },
	 *                 ),
	 *             ),
	 *         ),
	 *     );
	 *
	 * @since 4.6.0
	 *
	 * @param bool $enable_debug_mode Whether to enable debug mode checks to occur. Default true.
	 */
	if ( ! apply_filters( 'enable_wp_debug_mode_checks', true ) ) {
		return;
	}

	if ( WP_DEBUG ) {
		error_reporting( E_ALL );

		if ( WP_DEBUG_DISPLAY ) {
			ini_set( 'display_errors', 1 );
		} elseif ( null !== WP_DEBUG_DISPLAY ) {
			ini_set( 'display_errors', 0 );
		}

		if ( in_array( strtolower( (string) WP_DEBUG_LOG ), array( 'true', '1' ), true ) ) {
			$log_path = WP_CONTENT_DIR . '/debug.log';
		} elseif ( is_string( WP_DEBUG_LOG ) ) {
			$log_path = WP_DEBUG_LOG;
		} else {
			$log_path = false;
		}

		if ( $log_path ) {
			ini_set( 'log_errors', 1 );
			ini_set( 'error_log', $log_path );
		}
	} else {
		error_reporting( E_CORE_ERROR | E_CORE_WARNING | E_COMPILE_ERROR | E_ERROR | E_WARNING | E_PARSE | E_USER_ERROR | E_USER_WARNING | E_RECOVERABLE_ERROR );
	}

	/*
	 * The 'REST_REQUEST' check here is optimistic as the constant is most
	 * likely not set at this point even if it is in fact a REST request.
	 */
	if ( defined( 'XMLRPC_REQUEST' ) || defined( 'REST_REQUEST' ) || defined( 'MS_FILES_REQUEST' )
		|| ( defined( 'WP_INSTALLING' ) && WP_INSTALLING )
		|| wp_doing_ajax() || wp_is_json_request()
	) {
		ini_set( 'display_errors', 0 );
	}
}

debug