Firefox Cache Bug

Feb 23, 2006

I've run across an interesting bug in Firefox recently, but it's unfortunately the kind of problem that is incredibly difficult to track down. The header image here at this website wasn't showing up in my main Firefox profile on my PC. Other profiles worked, Internet Explorer worked, and the installation on my laptop also worked without a hitch. Trying to view the actual file in the problematic install (by entering the exact URL to the image in the address bar) only resulted in a "File Not Found" error page.

Doing a Bugzilla bug search, I ran across bug #312908, which seems to reference a similar issue. The comment in the bug reports that clearing the cache manually, then reloading the page, causes the problem to go away. Sure enough, that worked like a charm for me. Is this simply a cache problem? A more subtle rendering engine problem? It's hard to tell. Trying to reproduce the problem should be interesting.

If you run into a website that all of a sudden doesn't render properly, and you know the site isn't at fault, clear your cache and try again. Hopefully this is a bug that will get squashed as we head towards Firefox 2.0.



1:01 PM on Feb 23, 2006
I've noticed something like this before, where an image fails to load completely and then even typing the URL to the picture displays the half-loaded picture, even when I hit refresh. I've also seen a CSS file get cached- so I'd update my site from home, and at work the next day I'd see the changes to the content, but the CSS file would be old so it would be rendered wrong, even after refreshing. But it doesn't happen to me often.. like you said, it's a very difficult bug to track down. Of course, when I am using the web at work, there is another potential culprit: the company's proxy (which caches some stuff-- I know I've downloaded a fairly big zip file then deleted it, then decided I needed it and the second time I download it, it goes super fast like it's coming off the network).


2:40 AM on Feb 24, 2006
I ran into this bug again today (on a different machine) with precisely the problem you mentioned: the style sheet at Slashdot was not being rendered at all. Clearing the cache solved the problem. It's odd that I've run into this twice in the past few days, especially since I've never seen this problem before. Maybe one of the extensions I run is tickling this bug? Very odd. I'm just glad I have a solution.

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