From 490daba99cf1251b2950d11fa95a2d53f793540e Mon Sep 17 00:00:00 2001
From: Matthew Flaschen <mflaschen@wikimedia.org>
Date: Thu, 17 Nov 2016 17:51:07 -0500
Subject: [PATCH] populateContentModel: Invalidate content model and revision
 cache

The cache is computed from both the default values and the DB.

If someone visits the page when the wrong default value is there,
it will be cached.

When we populate the DB with the correct value (usually in preparation
for changing the namespace default), we need to invalidate the
potentially broken cache.

Change-Id: I995c0d9fdec529a456762571d5406d0bd0d33aed
---
 maintenance/populateContentModel.php | 45 +++++++++++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)

diff --git a/maintenance/populateContentModel.php b/maintenance/populateContentModel.php
index c6bd794e23..b41e0e0d6e 100644
--- a/maintenance/populateContentModel.php
+++ b/maintenance/populateContentModel.php
@@ -28,6 +28,10 @@ require_once __DIR__ . '/Maintenance.php';
  *  populateContentModel.php --ns=1 --table=page
  */
 class PopulateContentModel extends Maintenance {
+	protected $wikiId;
+
+	protected $wanCache;
+
 	public function __construct() {
 		parent::__construct();
 		$this->addDescription( 'Populate the various content_* fields' );
@@ -38,6 +42,11 @@ class PopulateContentModel extends Maintenance {
 
 	public function execute() {
 		$dbw = $this->getDB( DB_MASTER );
+
+		$this->wikiId = $dbw->getWikiID();
+
+		$this->wanCache = ObjectCache::getMainWANInstance();
+
 		$ns = $this->getOption( 'ns' );
 		if ( !ctype_digit( $ns ) && $ns !== 'all' ) {
 			$this->error( 'Invalid namespace', 1 );
@@ -57,6 +66,18 @@ class PopulateContentModel extends Maintenance {
 		}
 	}
 
+	protected function clearCache( $page_id, $rev_id ) {
+		$contentModelKey = $this->wanCache->makeKey( 'page', 'content-model', $rev_id );
+		$revisionKey =
+			$this->wanCache->makeGlobalKey( 'revision', $this->wikiId, $page_id, $rev_id );
+
+		// WikiPage content model cache
+		$this->wanCache->delete( $contentModelKey );
+
+		// Revision object cache, which contains a content model
+		$this->wanCache->delete( $revisionKey );
+	}
+
 	private function updatePageRows( Database $dbw, $pageIds, $model ) {
 		$count = count( $pageIds );
 		$this->output( "Setting $count rows to $model..." );
@@ -117,6 +138,7 @@ class PopulateContentModel extends Maintenance {
 			[ $key => $ids ],
 			__METHOD__
 		);
+
 		$this->output( "done.\n" );
 	}
 
@@ -130,19 +152,27 @@ class PopulateContentModel extends Maintenance {
 			$fields = [ 'ar_namespace', 'ar_title' ];
 			$join_conds = [];
 			$where = $ns === 'all' ? [] : [ 'ar_namespace' => $ns ];
+			$page_id_column = 'ar_page_id';
+			$rev_id_column = 'ar_rev_id';
 		} else { // revision
 			$selectTables = [ 'revision', 'page' ];
 			$fields = [ 'page_title', 'page_namespace' ];
 			$join_conds = [ 'page' => [ 'INNER JOIN', 'rev_page=page_id' ] ];
 			$where = $ns === 'all' ? [] : [ 'page_namespace' => $ns ];
+			$page_id_column = 'rev_page';
+			$rev_id_column = 'rev_id';
 		}
 
 		$toSave = [];
+		$idsToClear = [];
 		$lastId = 0;
 		do {
 			$rows = $dbw->select(
 				$selectTables,
-				array_merge( $fields, [ $model_column, $format_column, $key ] ),
+				array_merge(
+					$fields,
+					[ $model_column, $format_column, $key, $page_id_column, $rev_id_column ]
+				),
 				// @todo support populating format if model is already set
 				[
 					$model_column => null,
@@ -174,9 +204,17 @@ class PopulateContentModel extends Maintenance {
 				if ( $dbModel === null && $dbFormat === null ) {
 					// Set the defaults
 					$toSave[$defaultModel][] = $row->{$key};
+					$idsToClear[] = [
+						'page_id' => $row->{$page_id_column},
+						'rev_id' => $row->{$rev_id_column},
+					];
 				} else { // $dbModel === null, $dbFormat set.
 					if ( $dbFormat === $defaultFormat ) {
 						$toSave[$defaultModel][] = $row->{$key};
+						$idsToClear[] = [
+							'page_id' => $row->{$page_id_column},
+							'rev_id' => $row->{$rev_id_column},
+						];
 					} else { // non-default format, just update now
 						$this->output( "Updating model to match format for $table $id of $title... " );
 						$dbw->update(
@@ -186,6 +224,7 @@ class PopulateContentModel extends Maintenance {
 							__METHOD__
 						);
 						wfWaitForSlaves();
+						$this->clearCache( $row->{$page_id_column}, $row->{$rev_id_column} );
 						$this->output( "done.\n" );
 						continue;
 					}
@@ -200,6 +239,10 @@ class PopulateContentModel extends Maintenance {
 		foreach ( $toSave as $model => $ids ) {
 			$this->updateRevisionOrArchiveRows( $dbw, $ids, $model, $table );
 		}
+
+		foreach ( $idsToClear as $idPair ) {
+			$this->clearCache( $idPair['page_id'], $idPair['rev_id'] );
+		}
 	}
 }
 
-- 
2.20.1