111338 - a:hover background images not being cached.

Status: RESOLVED FIXED

(Core :: Graphics: ImageLib, defect)

Description

[Robert Clark]

When a background-image is set on a:hover in CSS, the image is not cached and is
reloaded on each mouseover.

Here are the HTTP headers from a packet capture:

GET /images/dot.png HTTP/1.1
Host: shard.sourceforge.net
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.6) Gecko/20011120
Accept: text/xml, application/xml, application/xhtml+xml, text/html;q=0.9,
image/png, image/jpeg, image/gif;q=0.2, text/plain;q=0.8, text/css, */*;q=0.1
Accept-Language: en-gb, en-us;q=0.50
Accept-Encoding: gzip, deflate, compress;q=0.9
Accept-Charset: ISO-8859-1, utf-8;q=0.66, *;q=0.66
Keep-Alive: 300
Connection: keep-alive
Pragma: no-cache
Cache-Control: no-cache

HTTP/1.1 200 OK
Date: Wed, 21 Nov 2001 23:22:14 GMT
Server: Apache/1.3.20 (Unix) PHP/4.0.6
Last-Modified: Wed, 21 Nov 2001 23:16:47 GMT
ETag: "1a485c-8f-3bfc35df"
Accept-Ranges: bytes
Content-Length: 143
Keep-Alive: timeout=15, max=100
Connection: Keep-Alive
Content-Type: image/png

The same request and response repeat several times on the same keep-alive HTTP
connection.

I have the cache set to compare automatically. The link is a simple test case.

Comment 1

[Boris Zbarsky [:bzbarsky]]

imagelib

Comment 2

[gordon]

Well, the headers include a pragma:no-cache and  Cache-control:no-cache.  That
might have something to do with it.  But shouldn't we at least keep it around
while the page is displayed?

Comment 3

[Robert Clark]

Actually, "the Pragma: no-cache" and  "Cache-control: no-cache" are _request_
headers from Mozilla, not response headers from the server. Mozilla is
requesting any caches between itself and the origin server revalidate their
copies before responding.

I've played around a little with response headers (Adding an Expires 1 year into
the future, adding "Cache-Control: public" and max-age/s-maxage at 1 year) but
with no effect.

Comment 4

[Robert Clark]

Did some more testing today, and I found that:

1) The bug is independent of the cache management preference setting. Even when
set to never validate cached pages (rather than automatically), the image is
reloaded repeatedly.

2) The bug is triggered by reloading the page. Specifically, to reproduce:

   a) Create a new profile
   b) visit http://shard.sourcefore.net/test/test.html
   c) move the mouse over the link a few times (no reloads occur)
   d) click "Reload"
   e) move the mouse over the link a few times (the image is repeatedly reloaded)

3) The reload is also triggered by moving the pointer without it leaving the
link area. When moving the mouse around over the link, I'm seeing around 2
requests per second for the background image.

4) I've been able to verify that the bug exists on Windows 2000 and I assume
it's affecting all OSes and all platforms.

Comment 5

[Robert Clark]

Is it possible that this is caused by the fix for bug 95981?

Comment 6

[Fabricio Campos Zuardi]

In the website http://www.aranhamagazine.com.br the links of the right side of
the site has the background hover image blinking when you mouse over them, my
cache options are: no memory cache,no disk cache and compare page never.

I'm using the build(2002021303) win2k.

Comment 7

[Andrew Hagen]

URL is dead. Other link does not seem to have any a:hover images.

Is this still a problem in Mozilla 1.3 alpha?

Comment 8

[HARUNAGA Hirotoshi]

Another testcase:
http://bugzilla.mozilla.gr.jp/attachment.cgi?id=831&action=view

Using Mozilla 1.1, the counter counts up on each mouseover.
But no problem now on 1.2 and later.
Worksforme?

Comment 9

[Robert Clark]

I've installed and tested 1.2 with both the URL (which still works for me) and
the new testcase and it certainly looks like it works.

Marking as fixed - thanks everyone.