From: Liangent <liangent@gmail.com>
Date: Thu, 5 Jun 2014 13:00:52 +0000 (+0000)
Subject: Load previous tags in ChangeTags::addTags() from DB_MASTER
X-Git-Tag: 1.31.0-rc.0~15459^2
X-Git-Url: http://git.cyclocoop.org/wiki/Target_page?a=commitdiff_plain;h=bc2ffb28d6ce667e6a6127e07e203a97150228c8;p=lhc%2Fweb%2Fwiklou.git

Load previous tags in ChangeTags::addTags() from DB_MASTER

This fixes a bug in mobile [1] that the tag added by MobileApp gets
overwritten by MobileFrontend, where both use ChangeTags::addTags(),
and MobileFrontend is registered (thus called) after MobileApp.

[1] http://lists.wikimedia.org/pipermail/mobile-l/2014-June/007260.html

Change-Id: Ie47649ef45f9eebdfeae73a0698ea5d21b150b56
---

diff --git a/includes/ChangeTags.php b/includes/ChangeTags.php
index d3dd51aa54..7e19164443 100644
--- a/includes/ChangeTags.php
+++ b/includes/ChangeTags.php
@@ -146,7 +146,10 @@ class ChangeTags {
 		);
 
 		## Update the summary row.
-		$prevTags = $dbr->selectField( 'tag_summary', 'ts_tags', $tsConds, __METHOD__ );
+		$dbw = wfGetDB( DB_MASTER );
+		// $prevTags can be out of date on slaves, especially when addTags is called consecutively,
+		// causing loss of tags added recently in tag_summary table.
+		$prevTags = $dbw->selectField( 'tag_summary', 'ts_tags', $tsConds, __METHOD__ );
 		$prevTags = $prevTags ? $prevTags : '';
 		$prevTags = array_filter( explode( ',', $prevTags ) );
 		$newTags = array_unique( array_merge( $prevTags, $tags ) );
@@ -158,7 +161,6 @@ class ChangeTags {
 			return false;
 		}
 
-		$dbw = wfGetDB( DB_MASTER );
 		$dbw->replace(
 			'tag_summary',
 			array( 'ts_rev_id', 'ts_rc_id', 'ts_log_id' ),