748692 - Dynamically created style rule gets disabled/removed

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Thomas Tampe]

Attachment: HTML page demonstrating the bug

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:12.0) Gecko/20100101 Firefox/12.0
Build ID: 20120420145725

Steps to reproduce:

I created a style node at runtime and added some style rules to it.
Then I changed the style node's className.
(see attached file for a working demonstration)


Actual results:

The styles did not apply.
It appears, the style rules got deleted.
According to http://forums.mozillazine.org/viewtopic.php?f=25&t=2461781 the same happens if an id is added to the style node.

Note: this works, if the classname is set to the style node before adding the rules.
But: remains a problem, since you can't change the classname.


Expected results:

The styles should apply even if you change the style node's classname.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Hmm.  nsHTMLStyleSheet::SetAttr reparses the stylesheet from the textnode contents unconditionally, looks like.  Jonas, is there a reason we're doing that instead of just doing it on changes to title/media/type attributes?

Comment 2

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

Yeah, the current code looks busted. I don't know of any reason we're doing what we're doing.

Comment 3

[Boris Zbarsky [:bzbarsky]]

Attachment: Don't reparse inline stylesheets on random attribute changes.

Comment 4

[Boris Zbarsky [:bzbarsky]]

http://hg.mozilla.org/integration/mozilla-inbound/rev/d13475bed11b

Comment 5

[Boris Zbarsky [:bzbarsky]]

Closed tree makes a liar of me.  Actual changeset: http://hg.mozilla.org/integration/mozilla-inbound/rev/3946bc720e97

Comment 6

[(no longer active)]

https://hg.mozilla.org/mozilla-central/rev/3946bc720e97