group,
		'label'             => '',
		'description'       => '',
		'sanitize_callback' => null,
		'show_in_rest'      => false,
	);

	// Back-compat: old sanitize callback is added.
	if ( is_callable( $args ) ) {
		$args = array(
			'sanitize_callback' => $args,
		);
	}

	/**
	 * Filters the registration arguments when registering a setting.
	 *
	 * @since 4.7.0
	 *
	 * @param array  $args         Array of setting registration arguments.
	 * @param array  $defaults     Array of default arguments.
	 * @param string $option_group Setting group.
	 * @param string $option_name  Setting name.
	 */
	$args = apply_filters( 'register_setting_args', $args, $defaults, $option_group, $option_name );

	$args = wp_parse_args( $args, $defaults );

	// Require an item schema when registering settings with an array type.
	if ( false !== $args['show_in_rest'] && 'array' === $args['type'] && ( ! is_array( $args['show_in_rest'] ) || ! isset( $args['show_in_rest']['schema']['items'] ) ) ) {
		_doing_it_wrong( __FUNCTION__, __( 'When registering an "array" setting to show in the REST API, you must specify the schema for each array item in "show_in_rest.schema.items".' ), '5.4.0' );
	}

	if ( ! is_array( $wp_registered_settings ) ) {
		$wp_registered_settings = array();
	}

	if ( 'misc' === $option_group ) {
		_deprecated_argument(
			__FUNCTION__,
			'3.0.0',
			sprintf(
				/* translators: %s: misc */
				__( 'The "%s" options group has been removed. Use another settings group.' ),
				'misc'
			)
		);
		$option_group = 'general';
	}

	if ( 'privacy' === $option_group ) {
		_deprecated_argument(
			__FUNCTION__,
			'3.5.0',
			sprintf(
				/* translators: %s: privacy */
				__( 'The "%s" options group has been removed. Use another settings group.' ),
				'privacy'
			)
		);
		$option_group = 'reading';
	}

	$new_allowed_options[ $option_group ][] = $option_name;

	if ( ! empty( $args['sanitize_callback'] ) ) {
		add_filter( "sanitize_option_{$option_name}", $args['sanitize_callback'] );
	}
	if ( array_key_exists( 'default', $args ) ) {
		add_filter( "default_option_{$option_name}", 'filter_default_option', 10, 3 );
	}

	/**
	 * Fires immediately before the setting is registered but after its filters are in place.
	 *
	 * @since 5.5.0
	 *
	 * @param string $option_group Setting group.
	 * @param string $option_name  Setting name.
	 * @param array  $args         Array of setting registration arguments.
	 */
	do_action( 'register_setting', $option_group, $option_name, $args );

	$wp_registered_settings[ $option_name ] = $args;
}

/**
 * Unregisters a setting.
 *
 * @since 2.7.0
 * @since 4.7.0 `$sanitize_callback` was deprecated. The callback from `register_setting()` is now used instead.
 * @since 5.5.0 `$new_whitelist_options` was renamed to `$new_allowed_options`.
 *              Please consider writing more inclusive code.
 *
 * @global array $new_allowed_options
 * @global array $wp_registered_settings
 *
 * @param string   $option_group The settings group name used during registration.
 * @param string   $option_name  The name of the option to unregister.
 * @param callable $deprecated   Optional. Deprecated.
 */
function unregister_setting( $option_group, $option_name, $deprecated = '' ) {
	global $new_allowed_options, $wp_registered_settings;

	/*
	 * In 5.5.0, the `$new_whitelist_options` global variable was renamed to `$new_allowed_options`.
	 * Please consider writing more inclusive code.
	 */
	$GLOBALS['new_whitelist_options'] = &$new_allowed_options;

	if ( 'misc' === $option_group ) {
		_deprecated_argument(
			__FUNCTION__,
			'3.0.0',
			sprintf(
				/* translators: %s: misc */
				__( 'The "%s" options group has been removed. Use another settings group.' ),
				'misc'
			)
		);
		$option_group = 'general';
	}

	if ( 'privacy' === $option_group ) {
		_deprecated_argument(
			__FUNCTION__,
			'3.5.0',
			sprintf(
				/* translators: %s: privacy */
				__( 'The "%s" options group has been removed. Use another settings group.' ),
				'privacy'
			)
		);
		$option_group = 'reading';
	}

	$pos = false;
	if ( isset( $new_allowed_options[ $option_group ] ) ) {
		$pos = array_search( $option_name, (array) $new_allowed_options[ $option_group ], true );
	}

	if ( false !== $pos ) {
		unset( $new_allowed_options[ $option_group ][ $pos ] );
	}

	if ( '' !== $deprecated ) {
		_deprecated_argument(
			__FUNCTION__,
			'4.7.0',
			sprintf(
				/* translators: 1: $sanitize_callback, 2: register_setting() */
				__( '%1$s is deprecated. The callback from %2$s is used instead.' ),
				'<code>$sanitize_callback</code>',
				'<code>register_setting()</code>'
			)
		);
		remove_filter( "sanitize_option_{$option_name}", $deprecated );
	}

	if ( isset( $wp_registered_settings[ $option_name ] ) ) {
		// Remove the sanitize callback if one was set during registration.
		if ( ! empty( $wp_registered_settings[ $option_name ]['sanitize_callback'] ) ) {
			remove_filter( "sanitize_option_{$option_name}", $wp_registered_settings[ $option_name ]['sanitize_callback'] );
		}

		// Remove the default filter if a default was provided during registration.
		if ( array_key_exists( 'default', $wp_registered_settings[ $option_name ] ) ) {
			remove_filter( "default_option_{$option_name}", 'filter_default_option', 10 );
		}

		/**
		 * Fires immediately before the setting is unregistered and after its filters have been removed.
		 *
		 * @since 5.5.0
		 *
		 * @param string $option_group Setting group.
		 * @param string $option_name  Setting name.
		 */
		do_action( 'unregister_setting', $option_group, $option_name );

		unset( $wp_registered_settings[ $option_name ] );
	}
}

/**
 * Retrieves an array of registered settings.
 *
 * @since 4.7.0
 *
 * @global array $wp_registered_settings
 *
 * @return array List of registered settings, keyed by option name.
 */
function get_registered_settings() {
	global $wp_registered_settings;

	if ( ! is_array( $wp_registered_settings ) ) {
		return array();
	}

	return $wp_registered_settings;
}

/**
 * Filters the default value for the option.
 *
 * For settings which register a default setting in `register_setting()`, this
 * function is added as a filter to `default_option_{$option}`.
 *
 * @since 4.7.0
 *
 * @param mixed  $default_value  Existing default value to return.
 * @param string $option         Option name.
 * @param bool   $passed_default Was `get_option()` passed a default value?
 * @return mixed Filtered default value.
 */
function filter_default_option( $default_value, $option, $passed_default ) {
	if ( $passed_default ) {
		return $default_value;
	}

	$registered = get_registered_settings();
	if ( empty( $registered[ $option ] ) ) {
		return $default_value;
	}

	return $registered[ $option ]['default'];
}

/**
 * Returns the values that trigger autoloading from the options table.
 *
 * @since 6.6.0
 *
 * @return string[] The values that trigger autoloading.
 */
function wp_autoload_values_to_autoload() {
	$autoload_values = array( 'yes', 'on', 'auto-on', 'auto' );

	/**
	 * Filters the autoload values that should be considered for autoloading from the options table.
	 *
	 * The filter can only be used to remove autoload values from the default list.
	 *
	 * @since 6.6.0
	 *
	 * @param string[] $autoload_values Autoload values used to autoload option.
	 *                               Default list contains 'yes', 'on', 'auto-on', and 'auto'.
	 */
	$filtered_values = apply_filters( 'wp_autoload_values_to_autoload', $autoload_values );

	return array_intersect( $filtered_values, $autoload_values );
}