Merge "Make interim WAN cache key deactivation logic broader"

diff --git a/includes/Setup.php b/includes/Setup.php
index 01f67c8..c9fe8d0 100644 (file)
--- a/includes/Setup.php
+++ b/includes/Setup.php
@@ -736,20 +736,22 @@ if ( !$wgDBerrorLogTZ ) {
 
 // Initialize the request object in $wgRequest
 $wgRequest = RequestContext::getMain()->getRequest(); // BackCompat
-// Set user IP/agent information for causal consistency purposes.
-// The cpPosIndex cookie has no prefix and is set by MediaWiki::preOutputCommit().
-$cpPosIndex = $wgRequest->getInt( 'cpPosIndex', (int)$wgRequest->getCookie( 'cpPosIndex', '' ) );
+// Set user IP/agent information for agent session consistency purposes
 MediaWikiServices::getInstance()->getDBLoadBalancerFactory()->setRequestInfo( [
        'IPAddress' => $wgRequest->getIP(),
        'UserAgent' => $wgRequest->getHeader( 'User-Agent' ),
        'ChronologyProtection' => $wgRequest->getHeader( 'ChronologyProtection' ),
-       'ChronologyPositionIndex' => $cpPosIndex
+       // The cpPosIndex cookie has no prefix and is set by MediaWiki::preOutputCommit()
+       'ChronologyPositionIndex' =>
+               $wgRequest->getInt( 'cpPosIndex', (int)$wgRequest->getCookie( 'cpPosIndex', '' ) )
 ] );
-// Make sure that caching does not compromise the consistency improvements
-if ( $cpPosIndex ) {
+// Make sure that object caching does not undermine the ChronologyProtector improvements
+if ( $wgRequest->getCookie( 'UseDC', '' ) === 'master' ) {
+       // The user is pinned to the primary DC, meaning that they made recent changes which should
+       // be reflected in their subsequent web requests. Avoid the use of interim cache keys because
+       // they use a blind TTL and could be stale if an object changes twice in a short time span.
        MediaWikiServices::getInstance()->getMainWANObjectCache()->useInterimHoldOffCaching( false );
 }
-unset( $cpPosIndex );
 
 // Useful debug output
 if ( $wgCommandLineMode ) {