From: Tim Starling <tstarling@wikimedia.org>
Date: Tue, 7 Oct 2014 05:24:45 +0000 (+1100)
Subject: HashBagOStuff: use the value itself as the CAS token
X-Git-Tag: 1.31.0-rc.0~13671
X-Git-Url: http://git.cyclocoop.org/%22%20.%20generer_url_ecrire%28%22articles%22%2C%22id_article=%24id_article%22%29%20.%20%22?a=commitdiff_plain;h=9f0d40e08f1b8b562d89457a6c1a0eb5dbfa7828;p=lhc%2Fweb%2Fwiklou.git

HashBagOStuff: use the value itself as the CAS token

Avoid an unnecessary serialize() call on get() requests, which makes it
faster and also happens to work around a nasty crash bug which is
causing lots of segfaults right now.

CAS semantics should be the same, if the caller handles a CAS token in
an opaque way and does not assume it is a string. I could only find one
caller of cas() in core and WMF deployed extensions, and that is
BagOStuff::mergeViaCas(), which does correctly handle CAS tokens of any
type.

Bug: 71724
Change-Id: I0b0b5f0157c005ec7f76210dfb8576c056314733
---

diff --git a/includes/objectcache/HashBagOStuff.php b/includes/objectcache/HashBagOStuff.php
index 6e50a8c39f..06a08655e9 100644
--- a/includes/objectcache/HashBagOStuff.php
+++ b/includes/objectcache/HashBagOStuff.php
@@ -65,7 +65,7 @@ class HashBagOStuff extends BagOStuff {
 			return false;
 		}
 
-		$casToken = serialize( $this->bag[$key][0] );
+		$casToken = $this->bag[$key][0];
 
 		return $this->bag[$key][0];
 	}
@@ -89,7 +89,7 @@ class HashBagOStuff extends BagOStuff {
 	 * @return bool
 	 */
 	function cas( $casToken, $key, $value, $exptime = 0 ) {
-		if ( serialize( $this->get( $key ) ) === $casToken ) {
+		if ( $this->get( $key ) === $casToken ) {
 			return $this->set( $key, $value, $exptime );
 		}