Admin notices accessibility

src/js/_enqueues/admin/common.js

@@ -1075,17 +1075,6 @@ $( function() {
 		});
 	}
 
-	/*
-	 * The `.below-h2` class is here just for backward compatibility with plugins
-	 * that are (incorrectly) using it. Do not use. Use `.inline` instead. See #34570.
-	 * If '.wp-header-end' is found, append the notices after it otherwise
-	 * after the first h1 or h2 heading found within the main content.
-	 */
-	if ( ! $headerEnd.length ) {
-		$headerEnd = $( '.wrap h1, .wrap h2' ).first();
-	}
-	$( 'div.updated, div.error, div.notice' ).not( '.inline, .below-h2' ).insertAfter( $headerEnd );
-
 	/**
 	 * Makes notices dismissible.
 	 *
@@ -1525,6 +1514,32 @@ $( function() {
 		input.on('change', toggleUploadButton);
 	})();
 
+	/**
+	 * Moves the admin notices into an `aside` element after the first `h1`.
+	 * Prior to 7.2.0, admin notices were only moved after the first `h1`;
+	 * The `aside` wrapper was added in 7.2.0.
+	 *
+	 * @since 7.2.0
+	 *
+	 * @return {void}
+	 */
+	function moveAdminNotices() {
+		/*
+		 * The `.below-h2` class is here just for backward compatibility with plugins
+		 * that are (incorrectly) using it. Do not use. Use `.inline` instead. See #34570.
+		 * If '.wp-header-end' is found, append the notices after it otherwise
+		 * after the first h1 or h2 heading found within the main content.
+		 */
+		if ( ! $headerEnd.length ) {
+			$headerEnd = $( '.wrap h1, .wrap h2' ).first();
+		}
+		const $notices = $( 'div.updated, div.error, div.notice' ).not( '.inline, .below-h2' );
+		if ( $notices.length ) {
+			const $wpAdminNotices = $( '<aside id="wp-admin-notices"></aside>' ).attr( 'aria-label', __( 'Admin Notices' ) ).insertAfter( $headerEnd );
+			$notices.appendTo( $wpAdminNotices );
+		}
+	}
+
 	/**
 	 * Pins the menu while distraction-free writing is enabled.
 	 *
@@ -2127,6 +2142,7 @@ $( function() {
 	});
 
 	window.wpResponsive.init();
+	moveAdminNotices();
 	setPinMenu();
 	setMenuState();
 	makeNoticesDismissible();

src/wp-admin/admin.php

@@ -101,6 +101,8 @@
 
 require_once ABSPATH . 'wp-admin/includes/admin.php';
 
+WP_Admin_Notice_Collector::init();
+
 auth_redirect();
 
 // Schedule Trash collection.

src/wp-includes/class-wp-admin-notice-collector.php

@@ -0,0 +1,165 @@
+<?php
+/**
+ * Administration API: WP_Admin_Notice_Collector class
+ *
+ * @package WordPress
+ * @subpackage Administration
+ * @since x.x.x
+ */
+
+/**
+ * Capture admin notices generated in PHP during a request.
+ *
+ * Notices are captured via the {@see 'wp_admin_notice_markup'} filter.
+ * a title placeholder is inserted into the admin page's `<title>` tag,
+ * the admin page title is modified via the {@see 'admin_title'}
+ * filter, the admin page is wrapped in an output buffer, and an
+ * `ob_start()` callback replaces the placeholder with the final count once
+ * the buffer is flushed.
+ *
+ * @since 7.2.0
+ */
+class WP_Admin_Notice_Collector {
+
+	/**
+	 * Placeholder inserted into the admin title, replaced with the
+	 * actual notice count once it is known.
+	 *
+	 * @since 7.2.0
+	 * @var string
+	 */
+	const TITLE_PLACEHOLDER = '%%wp_admin_notice_count%%';
+
+	/**
+	 * Notices captured during the current request.
+	 *
+	 * @since 7.2.0
+	 * @var array[]
+	 */
+	protected static $notices = array();
+
+	/**
+	 * Whether the collector's hooks have already been registered.
+	 *
+	 * @since 7.2.0
+	 * @var bool
+	 */
+	protected static $hooked = false;
+
+	/**
+	 * Registers the hooks used to collect notices and to annotate the admin title.
+	 *
+	 * @since 7.2.0
+	 */
+	public static function init() {
+		if ( self::$hooked ) {
+			return;
+		}
+
+		self::$hooked = true;
+
+		add_filter( 'wp_admin_notice_markup', array( __CLASS__, 'capture_notice' ), 10, 3 );
+
+		// Ajax/REST admin requests don't render a <title>, so skip the buffer there.
+		if ( is_admin() && ! wp_doing_ajax() ) {
+			add_filter( 'admin_title', array( __CLASS__, 'add_title_placeholder' ), 10, 2 );
+			ob_start( array( __CLASS__, 'inject_notice_count' ) );
+		}
+	}
+
+	/**
+	 * Captures a single admin notice without altering its markup.
+	 *
+	 * Hooked to the {@see 'wp_admin_notice_markup'} filter.
+	 *
+	 * @since 7.2.0
+	 *
+	 * @param string $markup  The HTML markup for the admin notice.
+	 * @param string $message The message for the admin notice.
+	 * @param array  $args    The arguments for the admin notice.
+	 * @return string The unmodified markup, so the filter remains transparent.
+	 */
+	public static function capture_notice( $markup, $message, $args ) {
+		if ( '' !== trim( wp_strip_all_tags( $message ) ) ) {
+			self::$notices[ $args['notice_id'] ] = array(
+				'markup'  => $markup,
+				'message' => $message,
+				'args'    => $args,
+			);
+		}
+
+		return $markup;
+	}
+
+	/**
+	 * Returns all notices captured during the current request.
+	 *
+	 * @since 7.2.0
+	 *
+	 * @return array[] Array of captured notices. Each entry contains the
+	 *                 notice's 'markup', 'message', and 'args'.
+	 */
+	public static function get_notices() {
+		return self::$notices;
+	}
+
+	/**
+	 * Returns the number of notices captured during the current request.
+	 *
+	 * @since 7.2.0
+	 *
+	 * @return int Notice count.
+	 */
+	public static function get_notice_count() {
+		return count( self::$notices );
+	}
+
+	/**
+	 * Clears all previously captured notices.
+	 *
+	 * @since 7.2.0
+	 */
+	public static function reset() {
+		self::$notices = array();
+	}
+
+	/**
+	 * Prepends a title placeholder via the {@see 'admin_title'} filter.
+	 *
+	 * The real count isn't known yet at this point, since notices are usually
+	 * produced later in the page. inject_notice_count() resolves it.
+	 *
+	 * @since 7.2.0
+	 *
+	 * @param string $admin_title The page title, with extra context added.
+	 * @param string $title       The original page title.
+	 * @return string The admin title with the placeholder prepended.
+	 */
+	public static function add_title_placeholder( $admin_title, $title ) {
+		return self::TITLE_PLACEHOLDER . $admin_title;
+	}
+
+	/**
+	 * Replaces the title placeholder with the final notice count.
+	 *
+	 * Used as an `ob_start()` callback so it runs once the full page - including
+	 * any notices printed after `<title>` - has been buffered.
+	 *
+	 * @since 7.2.0
+	 *
+	 * @param string $buffer The full buffered page output.
+	 * @return string The page output with the placeholder resolved.
+	 */
+	public static function inject_notice_count( $buffer ) {
+		$count = self::get_notice_count();
+
+		if ( 0 === $count ) {
+			return str_replace( self::TITLE_PLACEHOLDER, '', $buffer );
+		}
+
+		/* translators: %d: Number of admin notices on the current page. */
+		$prefix = sprintf( _n( '(%d notice) ', '(%d notices) ', $count ), $count );
+
+		return str_replace( self::TITLE_PLACEHOLDER, $prefix, $buffer );
+	}
+}

src/wp-includes/functions.php

@@ -9342,6 +9342,10 @@ function wp_get_admin_notice( $message, $args = array() ) {
 	 */
 	$args = apply_filters( 'wp_admin_notice_args', $args, $message );
 
+	// Unique ID is intended for internal use, and is not a filterable argument.
+	$unique_id         = wp_unique_prefixed_id( 'wp-admin-notice-' );
+	$args['notice_id'] = $unique_id;
+
 	$wrap_with_p  = false !== $args['paragraph_wrap'];
 	$wrap_opener  = $wrap_with_p ? '<p>' : '';
 	$wrap_closer  = $wrap_with_p ? '</p>' : '';
@@ -9351,9 +9355,15 @@ function wp_get_admin_notice( $message, $args = array() ) {
 	if ( is_string( $args['id'] ) ) {
 		$trimmed_id = trim( $args['id'] );
 
+		$html_builder->set_attribute( 'data-id', $unique_id );
 		if ( '' !== $trimmed_id ) {
 			$html_builder->set_attribute( 'id', $trimmed_id );
+		} else {
+			$html_builder->set_attribute( 'id', $unique_id );
 		}
+	} else {
+		$html_builder->set_attribute( 'data-id', $unique_id );
+		$html_builder->set_attribute( 'id', $unique_id );
 	}
 
 	if ( is_string( $args['type'] ) ) {

src/wp-settings.php

@@ -115,6 +115,7 @@
 require ABSPATH . WPINC . '/formatting.php';
 require ABSPATH . WPINC . '/meta.php';
 require ABSPATH . WPINC . '/functions.php';
+require ABSPATH . WPINC . '/class-wp-admin-notice-collector.php';
 require ABSPATH . WPINC . '/class-wp-meta-query.php';
 require ABSPATH . WPINC . '/class-wp-matchesmapregex.php';
 require ABSPATH . WPINC . '/class-wp.php';