308252 - Incorrect image is displayed (after redirect and with cache enabled)

Status: RESOLVED DUPLICATE of bug 89419

(Core :: Graphics: ImageLib, defect)

Description

[Alex Pankratov]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.10) Gecko/20050716 Firefox/1.0.6
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.10) Gecko/20050716 Firefox/1.0.6

If image SRC is pointing at URL that redirects to two or more different images,
then Mozilla will perform correct conditional GET, but will display invalid image.

Here's relevant HTML snippet - <img src="http://host/script.cgi">

script.cgi redirects to one of two images - http://host/img1.png and
http:/host/img2.png - flipping between them on every call.

If Mozilla is displaying img1.png and the page is refreshed, it will 
* receive a redirect to img2.png
* issue correct conditional GET for img2.png
* receive 304 (Not Modified) and 
* will _NOT_ render img2 on top img1, but will keep img1 instead.

Mozilla should change to displaying img2 as the last step - this is an expected
behaviour.

Reproducible: Always

Steps to Reproduce:
See Details.

Actual Results:  
See Details.


Expected Results:  
See Details.


Internet Explorer works as expected

Comment 1

[Josh Birnbaum]

Do you have a testcase you can point us to?  Or can you try it yourself with a
recent version of Firefox?

Comment 2

[Alex Pankratov]

Here -

http://hamachi.cc/bug/img.php redirects to either
http://hamachi.cc/bug/image1.png or
http://hamachi.cc/bug/image2.png

The image is changed every 4 seconds. img.php is as follows -

<?
        $var = (time() & 4) ? 1 : 2;
        header("Location: /bug/image" . $var . ".png");
?>

Point you browser to http://hamachi.cc/bug/img.html to reproduce the problem.
Just keep hitting refresh once a second for 12 seconds and you will see that
Mozilla will get stuck displaying one of the images. However if you right-click
on it and select View Image, the correct image will always be displayed.

HTH

Comment 3

[Josh Birnbaum]

I see the same behavior with SeaMonkey 2005090705.  Dug up an earlier report for
this; it's a bug in the image library.

*** This bug has been marked as a duplicate of 89419 ***