(This is probably actually a caching bug, but couldn't find where to file such bugs against. Feel free to reassign to a better component.)
I've seen this bug every once in a while ever since the 1.17 deploy, but was never able to reproduce it for debugging. I happened to catch it by accident with Firebug running today. It looks like what happened is:
- The browser requested the page itself, which loaded in half a second
- The browser next requested
http://bits.wikimedia.org/commons.wikimedia.org/load.php?debug=false&lang=en&modules=mediawiki.legacy.commonPrint%7Cmediawiki.legacy.shared%7Cskins.vector&only=styles&skin=vector
which waited for 6.2 seconds and then returned 0 bytes (but status 200 OK). The Cache headers on the response from bits were:
Last Modified Tue Apr 26 2011 18:29:19 GMT-0700 (PDT)
Last Fetched Tue Apr 26 2011 18:29:19 GMT-0700 (PDT)
Expires Wed Dec 31 1969 16:00:00 GMT-0800 (PST)
Data Size 0
Fetch Count 28
Device disk
Of course reloading the page fixed the problem, as it always does.
Version: 1.17.x
Severity: major