Removed doCascadeProtectionUpdates method to avoid DB writes on page views

* Use special prioritized refreshLinksJobs instead, which triggers when
  transcluded pages are changed
* Also added a triggerOpportunisticLinksUpdate() method to handle
  dynamic transcludes

bug: T89389
Change-Id: Iea952d4d2e660b7957eafb5f73fc87fab347dbe7

includes/DefaultSettings.php

@@ -6422,6 +6422,7 @@ $wgJobClasses = array(
 	'PublishStashedFile' => 'PublishStashedFileJob',
 	'ThumbnailRender' => 'ThumbnailRenderJob',
 	'recentChangesUpdate' => 'RecentChangesUpdateJob',
+	'refreshLinksPrioritized' => 'RefreshLinksJob', // for cascading protection
 	'null' => 'NullJob'
 );
 

includes/cache/BacklinkCache.php

@@ -487,4 +487,55 @@ class BacklinkCache {
 
 		return array( 'numRows' => $numRows, 'batches' => $batches );
 	}
+
+	/**
+	 * Get a Title iterator for cascade-protected template/file use backlinks
+	 *
+	 * @return TitleArray
+	 * @since 1.25
+	 */
+	public function getCascadeProtectedLinks() {
+		$dbr = $this->getDB();
+
+		// @todo: use UNION without breaking tests that use temp tables
+		$resSets = array();
+		$resSets[] = $dbr->select(
+			array( 'templatelinks', 'page_restrictions', 'page' ),
+			array( 'page_namespace', 'page_title', 'page_id' ),
+			array(
+				'tl_namespace' => $this->title->getNamespace(),
+				'tl_title' => $this->title->getDBkey(),
+				'tl_from = pr_page',
+				'pr_cascade' => 1,
+				'page_id = tl_from'
+			),
+			__METHOD__,
+			array( 'DISTINCT' )
+		);
+		if ( $this->title->getNamespace() == NS_FILE ) {
+			$resSets[] = $dbr->select(
+				array( 'imagelinks', 'page_restrictions', 'page' ),
+				array( 'page_namespace', 'page_title', 'page_id' ),
+				array(
+					'il_to' => $this->title->getDBkey(),
+					'il_from = pr_page',
+					'pr_cascade' => 1,
+					'page_id = il_from'
+				),
+				__METHOD__,
+				array( 'DISTINCT' )
+			);
+		}
+
+		// Combine and de-duplicate the results
+		$mergedRes = array();
+		foreach ( $resSets as $res ) {
+			foreach ( $res as $row ) {
+				$mergedRes[$row->page_id] = $row;
+			}
+		}
+
+		return TitleArray::newFromResult(
+			new FakeResultWrapper( array_values( $mergedRes ) ) );
+	}
 }

includes/deferred/HTMLCacheUpdate.php

@@ -43,7 +43,6 @@ class HTMLCacheUpdate implements DeferrableUpdate {
 	}
 
 	public function doUpdate() {
-
 		$job = new HTMLCacheUpdateJob(
 			$this->mTitle,
 			array(
@@ -63,6 +62,5 @@ class HTMLCacheUpdate implements DeferrableUpdate {
 				$job->run(); // just do the purge query now
 			} );
 		}
-
 	}
 }

includes/deferred/LinksUpdate.php

@@ -228,12 +228,24 @@ class LinksUpdate extends SqlDataUpdate {
 	 * Which means do LinksUpdate on all pages that include the current page,
 	 * using the job queue.
 	 */
-	function queueRecursiveJobs() {
+	protected function queueRecursiveJobs() {
 		self::queueRecursiveJobsForTable( $this->mTitle, 'templatelinks' );
 		if ( $this->mTitle->getNamespace() == NS_FILE ) {
 			// Process imagelinks in case the title is or was a redirect
 			self::queueRecursiveJobsForTable( $this->mTitle, 'imagelinks' );
 		}
+
+		$bc = $this->mTitle->getBacklinkCache();
+		// Get jobs for cascade-protected backlinks for a high priority queue.
+		// If meta-templates change to using a new template, the new template
+		// should be implicitly protected as soon as possible, if applicable.
+		// These jobs duplicate a subset of the above ones, but can run sooner.
+		// Which ever runs first generally no-ops the other one.
+		$jobs = array();
+		foreach ( $bc->getCascadeProtectedLinks() as $title ) {
+			$jobs[] = new RefreshLinksJob( $title, array( 'prioritize' => true ) );
+		}
+		JobQueueGroup::singleton()->push( $jobs );
 	}
 
 	/**
@@ -253,6 +265,7 @@ class LinksUpdate extends SqlDataUpdate {
 					"refreshlinks:{$table}:{$title->getPrefixedText()}"
 				)
 			);
+
 			JobQueueGroup::singleton()->push( $job );
 			JobQueueGroup::singleton()->deduplicateRootJob( $job );
 		}

includes/jobqueue/jobs/RefreshLinksJob.php

@@ -39,6 +39,10 @@ class RefreshLinksJob extends Job {
 
 	function __construct( $title, $params = '' ) {
 		parent::__construct( 'refreshLinks', $title, $params );
+		// A separate type is used just for cascade-protected backlinks
+		if ( !empty( $this->params['prioritize'] ) ) {
+			$this->command .= 'Prioritized';
+		}
 		// Base backlink update jobs and per-title update jobs can be de-duplicated.
 		// If template A changes twice before any jobs run, a clean queue will have:
 		//		(A base, A base)
@@ -100,6 +104,10 @@ class RefreshLinksJob extends Job {
 		return true;
 	}
 
+	/**
+	 * @param Title $title
+	 * @return bool
+	 */
 	protected function runForTitle( Title $title = null ) {
 		$linkCache = LinkCache::singleton();
 		$linkCache->clear();

includes/page/Article.php

@@ -707,7 +707,7 @@ class Article implements Page {
 		}
 
 		# Get the ParserOutput actually *displayed* here.
-		# Note that $this->mParserOutput is the *current* version output.
+		# Note that $this->mParserOutput is the *current*/oldid version output.
 		$pOutput = ( $outputDone instanceof ParserOutput )
 			? $outputDone // object fetched by hook
 			: $this->mParserOutput;

includes/page/WikiPage.php

@@ -3378,70 +3378,35 @@ class WikiPage implements Page, IDBAccessObject {
 	}
 
 	/**
-	 * Updates cascading protections
+	 * Opportunistically enqueue link update jobs given fresh parser output if useful
 	 *
-	 * @param ParserOutput $parserOutput ParserOutput object for the current version
+	 * @param ParserOutput $parserOutput Current version page output
+	 * @return bool Whether a job was pushed
+	 * @since 1.25
 	 */
-	public function doCascadeProtectionUpdates( ParserOutput $parserOutput ) {
-		if ( wfReadOnly() || !$this->mTitle->areRestrictionsCascading() ) {
-			return;
+	public function triggerOpportunisticLinksUpdate( ParserOutput $parserOutput ) {
+		if ( wfReadOnly() ) {
+			return false;
 		}
 
-		// templatelinks or imagelinks tables may have become out of sync,
-		// especially if using variable-based transclusions.
-		// For paranoia, check if things have changed and if
-		// so apply updates to the database. This will ensure
-		// that cascaded protections apply as soon as the changes
-		// are visible.
-
-		// Get templates from templatelinks and images from imagelinks
-		$id = $this->getId();
-
-		$dbLinks = array();
-
-		$dbr = wfGetDB( DB_SLAVE );
-		$res = $dbr->select( array( 'templatelinks' ),
-			array( 'tl_namespace', 'tl_title' ),
-			array( 'tl_from' => $id ),
-			__METHOD__
-		);
-
-		foreach ( $res as $row ) {
-			$dbLinks["{$row->tl_namespace}:{$row->tl_title}"] = true;
+		if ( $this->mTitle->areRestrictionsCascading() ) {
+			// If the page is cascade protecting, the links should really be up-to-date
+			$params = array( 'prioritize' => true );
+		} elseif ( $parserOutput->hasDynamicContent() ) {
+			// Assume the output contains time/random based magic words
+			$params = array();
+		} else {
+			// If the inclusions are deterministic, the edit-triggered link jobs are enough
+			return false;
 		}
 
-		$dbr = wfGetDB( DB_SLAVE );
-		$res = $dbr->select( array( 'imagelinks' ),
-			array( 'il_to' ),
-			array( 'il_from' => $id ),
-			__METHOD__
-		);
-
-		foreach ( $res as $row ) {
-			$dbLinks[NS_FILE . ":{$row->il_to}"] = true;
+		// Check if the last link refresh was before page_touched
+		if ( $this->getLinksTimestamp() < $this->getTouched() ) {
+			JobQueueGroup::singleton()->push( new RefreshLinksJob( $this->mTitle, $params ) );
+			return true;
 		}
 
-		// Get templates and images from parser output.
-		$poLinks = array();
-		foreach ( $parserOutput->getTemplates() as $ns => $templates ) {
-			foreach ( $templates as $dbk => $id ) {
-				$poLinks["$ns:$dbk"] = true;
-			}
-		}
-		foreach ( $parserOutput->getImages() as $dbk => $id ) {
-			$poLinks[NS_FILE . ":$dbk"] = true;
-		}
-
-		// Get the diff
-		$links_diff = array_diff_key( $poLinks, $dbLinks );
-
-		if ( count( $links_diff ) > 0 ) {
-			// Whee, link updates time.
-			// Note: we are only interested in links here. We don't need to get
-			// other DataUpdate items from the parser output.
-			$u = new LinksUpdate( $this->mTitle, $parserOutput, false );
-			$u->doUpdate();
-		}
+		return false;
 	}
 
 	/**

includes/parser/ParserOutput.php

@@ -879,6 +879,22 @@ class ParserOutput extends CacheTime {
 		$this->mLimitReportData[$key] = $value;
 	}
 
+	/**
+	 * Check whether the cache TTL was lowered due to dynamic content
+	 *
+	 * When content is determined by more than hard state (e.g. page edits),
+	 * such as template/file transclusions based on the current timestamp or
+	 * extension tags that generate lists based on queries, this return true.
+	 *
+	 * @return bool
+	 * @since 1.25
+	 */
+	public function hasDynamicContent() {
+		global $wgParserCacheExpireTime;
+
+		return $this->getCacheExpiry() < $wgParserCacheExpireTime;
+	}
+
 	/**
 	 * Get or set the prevent-clickjacking flag
 	 *

includes/poolcounter/PoolWorkArticleView.php

@@ -159,7 +159,7 @@ class PoolWorkArticleView extends PoolCounterWork {
 		}
 
 		if ( $isCurrent ) {
-			$this->page->doCascadeProtectionUpdates( $this->parserOutput );
+			$this->page->triggerOpportunisticLinksUpdate( $this->parserOutput );
 		}
 
 		return true;