Core-65593: Remove sitemap stylesheets

src/wp-includes/canonical.php

@@ -707,9 +707,7 @@ function redirect_canonical( $requested_url = null, $do_redirect = true ) {
 	}
 
 	// Remove trailing slash for robots.txt or sitemap requests.
-	if ( is_robots()
-		|| ! empty( get_query_var( 'sitemap' ) ) || ! empty( get_query_var( 'sitemap-stylesheet' ) )
-	) {
+	if ( is_robots() || ! empty( get_query_var( 'sitemap' ) ) ) {
 		$redirect['path'] = untrailingslashit( $redirect['path'] );
 	}
 

src/wp-includes/class-wp.php

@@ -748,7 +748,7 @@ public function handle_404() {
 
 		// Never 404 here for the admin, robots, favicon, or sitemaps.
 		// Sitemap routes send their own status in WP_Sitemaps::render_sitemaps().
-		if ( is_admin() || is_robots() || is_favicon() || is_sitemap() || get_query_var( 'sitemap-stylesheet' ) ) {
+		if ( is_admin() || is_robots() || is_favicon() || is_sitemap() ) {
 			$set_404 = false;
 
 			// If posts were found, check for paged content.

src/wp-includes/sitemaps/class-wp-sitemaps-renderer.php

@@ -20,6 +20,7 @@ class WP_Sitemaps_Renderer {
 	 * XSL stylesheet for styling a sitemap for web browsers.
 	 *
 	 * @since 5.5.0
+	 * @deprecated 7.2.0 Stylesheets are no longer supported.
 	 *
 	 * @var string
 	 */
@@ -29,6 +30,7 @@ class WP_Sitemaps_Renderer {
 	 * XSL stylesheet for styling a sitemap for web browsers.
 	 *
 	 * @since 5.5.0
+	 * @deprecated 7.2.0 Stylesheets are no longer supported.
 	 *
 	 * @var string
 	 */
@@ -38,81 +40,64 @@ class WP_Sitemaps_Renderer {
 	 * WP_Sitemaps_Renderer constructor.
 	 *
 	 * @since 5.5.0
+	 * @since 7.2.0 No longer sets up the stylesheets, which are no longer supported.
 	 */
-	public function __construct() {
-		$stylesheet_url = $this->get_sitemap_stylesheet_url();
-
-		if ( $stylesheet_url ) {
-			$this->stylesheet = '<?xml-stylesheet type="text/xsl" href="' . esc_url( $stylesheet_url ) . '" ?>';
-		}
-
-		$stylesheet_index_url = $this->get_sitemap_index_stylesheet_url();
-
-		if ( $stylesheet_index_url ) {
-			$this->stylesheet_index = '<?xml-stylesheet type="text/xsl" href="' . esc_url( $stylesheet_index_url ) . '" ?>';
-		}
-	}
+	public function __construct() {}
 
 	/**
 	 * Gets the URL for the sitemap stylesheet.
 	 *
 	 * @since 5.5.0
+	 * @deprecated 7.2.0 Stylesheets are no longer supported.
 	 *
-	 * @global WP_Rewrite $wp_rewrite WordPress rewrite component.
-	 *
-	 * @return string The sitemap stylesheet URL.
+	 * @return string Empty string.
 	 */
 	public function get_sitemap_stylesheet_url() {
-		global $wp_rewrite;
-
-		$sitemap_url = home_url( '/wp-sitemap.xsl' );
-
-		if ( ! $wp_rewrite->using_permalinks() ) {
-			$sitemap_url = home_url( '/?sitemap-stylesheet=sitemap' );
-		}
+		_deprecated_function( __METHOD__, '7.2.0' );
 
 		/**
 		 * Filters the URL for the sitemap stylesheet.
 		 *
 		 * If a falsey value is returned, no stylesheet will be used and
-		 * the "raw" XML of the sitemap will be displayed.
+		 * Following the deprecation of XSLT by browser manufacturers the
+		 * outcome of this filter is ignored.
 		 *
 		 * @since 5.5.0
+		 * @deprecated 7.2.0 Stylesheets are no longer supported.
 		 *
 		 * @param string $sitemap_url Full URL for the sitemaps XSL file.
 		 */
-		return apply_filters( 'wp_sitemaps_stylesheet_url', $sitemap_url );
+		apply_filters_deprecated( 'wp_sitemaps_stylesheet_url', array( '' ), '7.2.0' );
+
+		return '';
 	}
 
 	/**
 	 * Gets the URL for the sitemap index stylesheet.
 	 *
 	 * @since 5.5.0
+	 * @deprecated 7.2.0 Stylesheets are no longer supported.
 	 *
-	 * @global WP_Rewrite $wp_rewrite WordPress rewrite component.
-	 *
-	 * @return string The sitemap index stylesheet URL.
+	 * @return string Empty string.
 	 */
 	public function get_sitemap_index_stylesheet_url() {
-		global $wp_rewrite;
-
-		$sitemap_url = home_url( '/wp-sitemap-index.xsl' );
-
-		if ( ! $wp_rewrite->using_permalinks() ) {
-			$sitemap_url = home_url( '/?sitemap-stylesheet=index' );
-		}
+		_deprecated_function( __METHOD__, '7.2.0' );
 
 		/**
 		 * Filters the URL for the sitemap index stylesheet.
 		 *
 		 * If a falsey value is returned, no stylesheet will be used and
-		 * the "raw" XML of the sitemap index will be displayed.
+		 * Following the deprecation of XSLT by browser manufacturers the
+		 * outcome of this filter is ignored.
 		 *
 		 * @since 5.5.0
+		 * @deprecated 7.2.0 Stylesheets are no longer supported.
 		 *
 		 * @param string $sitemap_url Full URL for the sitemaps index XSL file.
 		 */
-		return apply_filters( 'wp_sitemaps_stylesheet_index_url', $sitemap_url );
+		apply_filters_deprecated( 'wp_sitemaps_stylesheet_index_url', array( '' ), '7.2.0' );
+
+		return '';
 	}
 
 	/**
@@ -144,11 +129,12 @@ public function render_index( $sitemaps ) {
 	 * @return string|false A well-formed XML string for a sitemap index. False on error.
 	 */
 	public function get_sitemap_index_xml( $sitemaps ) {
+		$this->apply_deprecated_stylesheet_filters( 'index' );
+
 		$sitemap_index = new SimpleXMLElement(
 			sprintf(
-				'%1$s%2$s%3$s',
+				'%1$s%2$s',
 				'<?xml version="1.0" encoding="UTF-8" ?>',
-				$this->stylesheet_index,
 				'<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" />'
 			)
 		);
@@ -208,11 +194,12 @@ public function render_sitemap( $url_list ) {
 	 * @return string|false A well-formed XML string for a sitemap index. False on error.
 	 */
 	public function get_sitemap_xml( $url_list ) {
+		$this->apply_deprecated_stylesheet_filters( 'sitemap' );
+
 		$urlset = new SimpleXMLElement(
 			sprintf(
-				'%1$s%2$s%3$s',
+				'%1$s%2$s',
 				'<?xml version="1.0" encoding="UTF-8" ?>',
-				$this->stylesheet,
 				'<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" />'
 			)
 		);
@@ -243,6 +230,56 @@ public function get_sitemap_xml( $url_list ) {
 		return $urlset->asXML();
 	}
 
+	/**
+	 * Applies the removed stylesheet filters so that their callbacks trigger deprecation notices.
+	 *
+	 * The stylesheet filters no longer have any effect. Applying them where a sitemap is
+	 * generated ensures a callback still added to one is reported rather than silently ignored.
+	 * No notice is triggered for a filter that has no callbacks.
+	 *
+	 * @since 7.2.0
+	 *
+	 * @param 'sitemap'|'index' $type Sitemap type.
+	 */
+	private function apply_deprecated_stylesheet_filters( string $type ): void {
+		if ( 'index' === $type ) {
+			/** This filter is documented in wp-includes/sitemaps/class-wp-sitemaps-renderer.php */
+			apply_filters_deprecated( 'wp_sitemaps_stylesheet_index_url', array( '' ), '7.2.0' );
+
+			/**
+			 * Filters the content of the sitemap index stylesheet.
+			 *
+			 * Following the deprecation of XSLT by browser manufacturers the
+			 * outcome of this filter is ignored.
+			 *
+			 * @since 5.5.0
+			 * @deprecated 7.2.0 Stylesheets are no longer supported.
+			 *
+			 * @param string $xsl_content Full content for the XML stylesheet.
+			 */
+			apply_filters_deprecated( 'wp_sitemaps_stylesheet_index_content', array( '' ), '7.2.0' );
+		} else {
+			/** This filter is documented in wp-includes/sitemaps/class-wp-sitemaps-renderer.php */
+			apply_filters_deprecated( 'wp_sitemaps_stylesheet_url', array( '' ), '7.2.0' );
+
+			/**
+			 * Filters the content of the sitemap stylesheet.
+			 *
+			 * Following the deprecation of XSLT by browser manufacturers the
+			 * outcome of this filter is ignored.
+			 *
+			 * @since 5.5.0
+			 * @deprecated 7.2.0 Stylesheets are no longer supported.
+			 *
+			 * @param string $xsl_content Full content for the XML stylesheet.
+			 */
+			apply_filters_deprecated( 'wp_sitemaps_stylesheet_content', array( '' ), '7.2.0' );
+		}
+
+		/** This filter is documented in wp-includes/sitemaps/class-wp-sitemaps-stylesheet.php */
+		apply_filters_deprecated( 'wp_sitemaps_stylesheet_css', array( '' ), '7.2.0' );
+	}
+
 	/**
 	 * Checks for the availability of the SimpleXML extension and errors if missing.
 	 *