From fb69ee48d33b349fd63e363e0e25770aab17b48f Mon Sep 17 00:00:00 2001
From: Antoine Musso <hashar@free.fr>
Date: Mon, 28 May 2012 10:20:19 +0200
Subject: [PATCH] (bug 37072) - prevents infinite job loop

nextJob.php does not honor jobs types being excluded from the default
job queue by using $wgJobTypesExcludedFromDefaultQueue. Since those jobs
can never get processed, nextJob.php will always return a database which
might produce a nasty infinite loop while trying to process the whole
queue.

Job::pop did take in account wgJobTypesExcludedFromDefaultQueue to
filter the jobs out. So this patch factor out the code in a new method
and uses it for nextJob.php.

Change-Id: I15197ffcca00f229c9004e2abd87e009bc40f384
---
 includes/job/JobQueue.php | 30 +++++++++++++++++++++++-------
 maintenance/nextJobDB.php |  3 ++-
 2 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/includes/job/JobQueue.php b/includes/job/JobQueue.php
index 00652473cb..a3493b4a1a 100644
--- a/includes/job/JobQueue.php
+++ b/includes/job/JobQueue.php
@@ -113,7 +113,6 @@ abstract class Job {
 	 * @return Job or false if there's no jobs
 	 */
 	static function pop( $offset = 0 ) {
-		global $wgJobTypesExcludedFromDefaultQueue;
 		wfProfileIn( __METHOD__ );
 
 		$dbr = wfGetDB( DB_SLAVE );
@@ -124,12 +123,9 @@ abstract class Job {
 			NB: If random fetch previously was used, offset
 				will always be ahead of few entries
 		*/
-		$conditions = array();
-		if ( count( $wgJobTypesExcludedFromDefaultQueue ) != 0 ) {
-			foreach ( $wgJobTypesExcludedFromDefaultQueue as $cmdType ) {
-				$conditions[] = "job_cmd != " . $dbr->addQuotes( $cmdType );
-			}
-		}
+
+		$conditions = self::defaultQueueConditions();
+
 		$offset = intval( $offset );
 		$options = array( 'ORDER BY' => 'job_id', 'USE INDEX' => 'PRIMARY' );
 
@@ -318,6 +314,26 @@ abstract class Job {
 		wfIncrStats( 'job-insert', count( $jobs ) );
 	}
 
+
+	/**
+	 * SQL conditions to apply on most JobQueue queries
+	 *
+	 * Whenever we exclude jobs types from the default queue, we want to make
+	 * sure that queries to the job queue actually ignore them.
+	 *
+	 * @return array SQL conditions suitable for Database:: methods
+	 */
+	static function defaultQueueConditions( ) {
+		global $wgJobTypesExcludedFromDefaultQueue;
+		$conditions = array();
+		if ( count( $wgJobTypesExcludedFromDefaultQueue ) > 0 ) {
+			foreach ( $wgJobTypesExcludedFromDefaultQueue as $cmdType ) {
+				$conditions[] = "job_cmd != " . $dbr->addQuotes( $cmdType );
+			}
+		}
+		return $conditions;
+	}
+
 	/*-------------------------------------------------------------------------
 	 * Non-static functions
 	 *------------------------------------------------------------------------*/
diff --git a/maintenance/nextJobDB.php b/maintenance/nextJobDB.php
index 67aa3088c2..d9bd3b8880 100644
--- a/maintenance/nextJobDB.php
+++ b/maintenance/nextJobDB.php
@@ -94,11 +94,12 @@ class nextJobDB extends Maintenance {
 		$lb = wfGetLB( $dbName );
 		$db = $lb->getConnection( DB_MASTER, array(), $dbName );
 		if ( $type === false ) {
-			$conds = array();
+			$conds = JobQueue::defaultQueueConditions( );
 		} else {
 			$conds = array( 'job_cmd' => $type );
 		}
 
+
 		$exists = (bool) $db->selectField( 'job', '1', $conds, __METHOD__ );
 		$lb->reuseConnection( $db );
 		return $exists;
-- 
2.20.1