(bug 26130) ob_start( 'ob_gzhandler' ) in LocalSettings.php broke gzip output from...

diff --git a/includes/resourceloader/ResourceLoader.php b/includes/resourceloader/ResourceLoader.php
index e4677d0..834aced 100644 (file)
--- a/includes/resourceloader/ResourceLoader.php
+++ b/includes/resourceloader/ResourceLoader.php
@@ -287,6 +287,15 @@ class ResourceLoader {
         */
        public function respond( ResourceLoaderContext $context ) {
                global $wgResourceLoaderMaxage, $wgCacheEpoch;
+               
+               // Buffer output to catch warnings. Normally we'd use ob_clean() on the
+               // top-level output buffer to clear warnings, but that breaks when ob_gzhandler
+               // is used: ob_clean() will clear the GZIP header in that case and it won't come
+               // back for subsequent output, resulting in invalid GZIP. So we have to wrap
+               // the whole thing in our own output buffer to be sure the active buffer
+               // doesn't use ob_gzhandler.
+               // See http://bugs.php.net/bug.php?id=36514
+               ob_start();
 
                wfProfileIn( __METHOD__ );
 
@@ -353,6 +362,19 @@ class ResourceLoader {
                if ( $ims !== false ) {
                        $imsTS = strtok( $ims, ';' );
                        if ( $mtime <= wfTimestamp( TS_UNIX, $imsTS ) ) {
+                               // There's another bug in ob_gzhandler (see also the comment at
+                               // the top of this function) that causes it to gzip even empty
+                               // responses, meaning it's impossible to produce a truly empty
+                               // response (because the gzip header is always there). This is
+                               // a problem because 304 responses have to be completely empty
+                               // per the HTTP spec, and Firefox behaves buggily when they're not.
+                               // See also http://bugs.php.net/bug.php?id=51579
+                               // To work around this, we tear down all output buffering before
+                               // sending the 304.
+                               while ( ob_get_level() > 0 ) {
+                                       ob_end_clean();
+                               }
+                               
                                header( 'HTTP/1.0 304 Not Modified' );
                                header( 'Status: 304 Not Modified' );
                                wfProfileOut( __METHOD__ );
@@ -363,13 +385,14 @@ class ResourceLoader {
                // Generate a response
                $response = $this->makeModuleResponse( $context, $modules, $missing );
 
-               // Tack on PHP warnings as a comment in debug mode
+               // Capture any PHP warnings from the output buffer and append them to the
+               // response in a comment if we're in debug mode.
                if ( $context->getDebug() && strlen( $warnings = ob_get_contents() ) ) {
                        $response .= "/*\n$warnings\n*/";
                }
 
-               // Clear any warnings from the buffer
-               ob_clean();
+               // Remove the output buffer and output the response
+               ob_end_clean();
                echo $response;
 
                wfProfileOut( __METHOD__ );