798301 - A HTTP Status 304 message will occasionally cause an error 404-page to be (incorrectly) shown by firefox instead

Status: RESOLVED DUPLICATE of bug 771832

(Firefox :: Untriaged, defect)

Description

[M. Sokolewicz]

I am using a fresh MediaWiki installation, which makes heavy use of pages returning HTTP status codes 304 (Not Modified). Firefox should return the cached version, or send back a response to send a proper version if the cached can not be found. However, occasionally, FireFox will instead treat these pages as if they returned an error 404 (Not Found), showing its own "cute" version of a 404-page.

The headers sent when encountering such a problem are:
GET /wiki/Meeting_Notes HTTP/1.1
Host: www.example.com
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:18.0) Gecko/18.0 Firefox/18.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: http://www.example.com/wiki/Main_Page
Cookie: wicns_wikiUserID=1; wicns_wikiUserName=Username
Connection: keep-alive
If-Modified-Since: Fri, 05 Oct 2012 12:25:51 GMT

Returned headers:
HTTP/1.1 304 Not Modified
Date: Fri, 05 Oct 2012 12:34:04 GMT
Server: Apache
Connection: Keep-Alive
Keep-Alive: timeout=5, max=97
Expires: Thu, 01 Jan 1970 00:00:00 GMT
Cache-Control: private, must-revalidate, max-age=0
Vary: Accept-Encoding,Cookie
X-Pad: avoid browser bug

I am currently using Firefox nightly, version 18.0a1 (2012-10-04)

Comment 1

[M. Sokolewicz]

Problem is still present in 18.0a1 (2012-10-05)

Comment 2

[M. Sokolewicz]

Refreshing/reloading the page (F5) does not resolve the issue. However, refreshing while skipping the cache (CTRL+F5) does resolve the issue. However, the problem soon thereafter reappears.

Comment 3

[Matthias Versen [:Matti]]

This loooks like a dupe of bug 771832