Add tracking categories for errors

Two tracking categories are added:
* A category to track stylesheets with errors. While it's usually not
  possible to save a stylesheet with errors, it can happen if a
  server-side change makes formerly-valid CSS become invalid.
* A category to track pages displaying errors from incorrect use of
  the <templatestyles/> tag.

Bug: T195676
Change-Id: I123679d4bffe36cb28aca1688c052470027ea2a8

extension.json

@@ -30,6 +30,10 @@
 	"ContentHandlers": {
 		"sanitized-css": "TemplateStylesContentHandler"
 	},
+	"TrackingCategories": [
+		"templatestyles-stylesheet-error-category",
+		"templatestyles-page-error-category"
+	],
 	"SyntaxHighlightModels": {
 		"sanitized-css": "css"
 	},

i18n/en.json

@@ -15,6 +15,10 @@
 	"templatestyles-size-exceeded": "The stylesheet is larger than the maximum size of $2.",
 	"templatestyles-end-tag-injection": "The supplied stylesheet contains <code>&lt;/style</code>, which is not allowed.",
 	"content-model-sanitized-css": "Sanitized CSS",
+	"templatestyles-stylesheet-error-category": "TemplateStyles stylesheets with errors",
+	"templatestyles-stylesheet-error-category-desc": "The TemplateStyles stylesheet has an error.",
+	"templatestyles-page-error-category": "Pages with TemplateStyles errors",
+	"templatestyles-page-error-category-desc": "There was an error when processing a <code><nowiki><templatestyles/></nowiki></code> tag on the page.",
 
 	"templatestyles-error-at-rule-block-not-allowed": "Block not allowed for <code>@$3</code> at line $1 character $2.",
 	"templatestyles-error-at-rule-block-required": "Block required for <code>@$3</code> at line $1 character $2.",

i18n/qqq.json

@@ -17,6 +17,10 @@
 	"templatestyles-size-exceeded": "Error returned when the stylesheet is more than $wgTemplateStylesMaxStylesheetSize bytes. Parameters:\n* $1 - Maximum size in bytes\n* $2 - Maximum size in \"human units\" (i.e. KB, MB, GB, etc).",
 	"templatestyles-end-tag-injection": "Error returned when the stylesheet contains <code>&lt;/style</code>, which is likely an attempt at HTML injection.",
 	"content-model-sanitized-css": "Name for TemplateStyles sanitized-css content model.",
+	"templatestyles-stylesheet-error-category": "Tracking category for TemplateStyles stylesheets with errors.",
+	"templatestyles-stylesheet-error-category-desc": "Description on [[Special:TrackingCategories]] for the {{msg-mw|templatestyles-stylesheet-error-category}} tracking category.",
+	"templatestyles-page-error-category": "Tracking category for pages with errors from <code><nowiki><templatestyles/></nowiki></code>.",
+	"templatestyles-page-error-category-desc": "Description on [[Special:TrackingCategories]] for the {{msg-mw|templatestyles-page-error-category}} tracking category.",
 	"templatestyles-error-at-rule-block-not-allowed": "Error in CSS validation. Note \"block\" in this message refers to the part of CSS syntax inside the <code>{ ... }</code>. Parameters:\n* $1 - Line number of the error.\n* $2 - Location of the error within the line.\n* $3 - Name of the at-rule in question.",
 	"templatestyles-error-at-rule-block-required": "Error in CSS validation. Note \"block\" in this message refers to the part of CSS syntax inside the <code>{ ... }</code>. Parameters:\n* $1 - Line number of the error.\n* $2 - Location of the error within the line.\n* $3 - Name of the at-rule in question.",
 	"templatestyles-error-bad-character-in-url": "Error in CSS parsing. Parameters:\n* $1 - Line number of the error.\n* $2 - Location of the error within the line.",

includes/TemplateStylesContent.php

@@ -129,10 +129,13 @@ class TemplateStylesContent extends TextContent {
 		// Inject our warnings into the resulting ParserOutput
 		$po = parent::getParserOutput( $title, $revId, $options, $generateHtml );
 		$status = $this->sanitize( [ 'novalue' => true, 'class' => $options->getWrapOutputClass() ] );
-		foreach ( $status->getErrors() as $error ) {
-			$po->addWarning(
-				Message::newFromSpecifier( array_merge( [ $error['message'] ], $error['params'] ) )->parse()
-			);
+		if ( $status->getErrors() ) {
+			foreach ( $status->getErrors() as $error ) {
+				$po->addWarning(
+					Message::newFromSpecifier( array_merge( [ $error['message'] ], $error['params'] ) )->parse()
+				);
+			}
+			$po->addTrackingCategory( 'templatestyles-stylesheet-error-category', $title );
 		}
 		return $po;
 	}

includes/TemplateStylesHooks.php

@@ -204,9 +204,7 @@ class TemplateStylesHooks {
 		}
 
 		if ( !isset( $params['src'] ) || trim( $params['src'] ) === '' ) {
-			return '<strong class="error">' .
-				wfMessage( 'templatestyles-missing-src' )->inContentLanguage()->parse() .
-				'</strong>';
+			return self::formatTagError( $parser, [ 'templatestyles-missing-src' ] );
 		}
 
 		// Default to the Template namespace because that's the most likely
@@ -215,9 +213,7 @@ class TemplateStylesHooks {
 		// wind up wanting to make that relative to the wrong page.
 		$title = Title::newFromText( $params['src'], NS_TEMPLATE );
 		if ( !$title ) {
-			return '<strong class="error">' .
-				wfMessage( 'templatestyles-invalid-src' )->inContentLanguage()->parse() .
-				'</strong>';
+			return self::formatTagError( $parser, [ 'templatestyles-invalid-src' ] );
 		}
 
 		$rev = $parser->fetchCurrentRevisionOfTitle( $title );
@@ -229,24 +225,20 @@ class TemplateStylesHooks {
 		$content = $rev ? $rev->getContent() : null;
 		if ( !$content ) {
 			$title = $title->getPrefixedText();
-			return '<strong class="error">' .
-				wfMessage(
-					'templatestyles-bad-src-missing',
-					$title,
-					wfEscapeWikiText( $title )
-				)->inContentLanguage()->parse() .
-				'</strong>';
+			return self::formatTagError( $parser, [
+				'templatestyles-bad-src-missing',
+				$title,
+				wfEscapeWikiText( $title )
+			] );
 		}
 		if ( !$content instanceof TemplateStylesContent ) {
 			$title = $title->getPrefixedText();
-			return '<strong class="error">' .
-				wfMessage(
-					'templatestyles-bad-src',
-					$title,
-					wfEscapeWikiText( $title ),
-					ContentHandler::getLocalizedName( $content->getModel() )
-				)->inContentLanguage()->parse() .
-				'</strong>';
+			return self::formatTagError( $parser, [
+				'templatestyles-bad-src',
+				$title,
+				wfEscapeWikiText( $title ),
+				ContentHandler::getLocalizedName( $content->getModel() )
+			] );
 		}
 
 		// If the revision actually has an ID, cache based on that.
@@ -310,4 +302,17 @@ class TemplateStylesHooks {
 		return $ret;
 	}
 
+	/**
+	 * Format an error in the `<templatestyles>` tag
+	 * @param Parser $parser
+	 * @param array $msg Arguments to wfMessage()
+	 * @return string HTML
+	 */
+	private static function formatTagError( Parser $parser, array $msg ) {
+		$parser->addTrackingCategory( 'templatestyles-page-error-category' );
+		return '<strong class="error">' .
+			call_user_func_array( 'wfMessage', $msg )->inContentLanguage()->parse() .
+			'</strong>';
+	}
+
 }