Bug 166683

Summary: [GTK] Graphical artifacts on various Fedora websites when scrolling
Product: WebKit Reporter: Michael Catanzaro <mcatanzaro>
Component: WebKitGTKAssignee: Nobody <webkit-unassigned>
Status: UNCONFIRMED ---    
Severity: Normal CC: bugs-noreply, magomez, mcatanzaro, svillar
Priority: P2    
Version: WebKit Nightly Build   
Hardware: PC   
OS: Linux   
Attachments:
Description Flags
Screenshot of bug
none
Screenshot showcasing the problem
none
Ephy Tech Preview screenshot none

Description Michael Catanzaro 2017-01-04 05:20:19 PST
Created attachment 298007 [details]
Screenshot of bug

Visit any Fedora wiki page, e.g. https://fedoraproject.org/wiki/Changes/pkgconf_as_system_pkg-config_implementation, in 2.14 and scroll down. We have bad rendering trouble handling the Fedora overlay logo. Screenshot attached.

I think this is the same bug that has broken the reddit frontpage quite badly.

It is definitely fixed in my jhbuild environment, but I'm not sure if it's due to a change in WebKit or some other package.

Disabling/enabling compositing mode has no effect.
Comment 1 Michael Catanzaro 2017-01-05 21:30:30 PST
No clue what happened here, but it was an Epiphany problem. I "solved" it by downgrading and upgrading my Epiphany package. Very strange as that means nothing should have changed....
Comment 2 Michael Catanzaro 2017-02-04 10:55:18 PST
(In reply to comment #1)
> No clue what happened here, but it was an Epiphany problem. I "solved" it by
> downgrading and upgrading my Epiphany package. Very strange as that means
> nothing should have changed....

This is still broken, but it doesn't happen always. I guess I tricked myself into thinking it was solved. It happens on tons of Fedora websites, e.g.:

https://retrace.fedoraproject.org/faf/problems/2645453/

or:

http://pkgs.fedoraproject.org/cgit/rpms/webkitgtk4.git/log/

Just scroll down. Looks like we're not handling layers properly somehow.
Comment 3 Miguel Gomez 2017-03-01 04:22:43 PST
Michael, are you still able to reproduce this? Works fine for me on ToT. Maybe it's already fixed there.
Comment 4 Michael Catanzaro 2017-03-01 06:38:37 PST
The problem is it sometimes works perfectly fine for hours or days. :/ I don't know what causes WebKit to get into this broken state.
Comment 5 Michael Catanzaro 2017-03-03 14:10:25 PST
(In reply to comment #4)
> The problem is it sometimes works perfectly fine for hours or days. :/ I
> don't know what causes WebKit to get into this broken state.

I'm seeing the issue right now with 2.14.5.
Comment 6 Sergio Villar Senin 2018-02-23 06:58:05 PST
Created attachment 334528 [details]
Screenshot showcasing the problem

I think the very same is happening to me in a page with flash content. See attached the output of https://www.expert-chess-strategies.com/learn-chess-online.html

The artifacts appear once you scroll. Then if you go on scrolling they eventually dissapear and re-appear in some other ways.
Comment 7 Sergio Villar Senin 2018-02-23 06:59:16 PST
(In reply to Sergio Villar Senin from comment #6)
> Created attachment 334528 [details]
> Screenshot showcasing the problem
> 
> I think the very same is happening to me in a page with flash content. See
> attached the output of
> https://www.expert-chess-strategies.com/learn-chess-online.html
> 
> The artifacts appear once you scroll. Then if you go on scrolling they
> eventually dissapear and re-appear in some other ways.

BTW this happens with 2.18.6 and also today's ToT
Comment 8 Michael Catanzaro 2018-03-01 07:17:09 PST
This one is really weird. This bug is definitely not related to any particular upgrade. It just comes and goes, seemingly at random, after updating WebKit. After another update or two, I won't notice it anymore, but it will be back again after some future update.
Comment 9 Michael Catanzaro 2018-04-16 12:16:29 PDT
Created attachment 338024 [details]
Ephy Tech Preview screenshot