emesene crashes with assertion failed in gtkstylecontext.c

[Riccardo 'c10ud']

this is NOT the version of emesene in precise archives.
It's a development version with experimental pygi support through pygicompat.

This happens _randomly_ (sometimes it crashes, sometimes it does not) when switching to login window to another window.
The login window contains a bunch of standard widgets and a gif animation.

[Riccardo 'c10ud' (c10ud)]

console shows:

Gtk:ERROR:/build/buildd/gtk+3.0-3.4.2/./gtk/gtkstylecontext.c:739:timeline_finished_cb: assertion failed: (info != NULL)

[Riccardo 'c10ud' (c10ud)]

ProblemType: Crash
Architecture: amd64
Date: Tue May 22 12:03:15 2012
DistroRelease: Ubuntu 12.04
ExecutablePath: /usr/bin/python2.7

ProcEnviron:
 TERM=xterm
 SHELL=/bin/bash
 PATH=(custom, no user)
 LANG=en_US.UTF-8

[Riccardo 'c10ud' (c10ud)]

how to reproduce:

[12:42] <c10ud> wget https://github.com/emesene/emesene/zipball/master
[12:42] <c10ud> extract
[12:42] <c10ud> USE_GI=1 ./emesene
[12:43] <c10ud> then select "dummy" session, put some random acc/pwd and connect
[12:44] <c10ud> since it doesn't happen everytime you can check autologin and ctrl+c from terminal when you see the fake contact list (seeing the contact list means bug hasn't been triggered)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Riccardo 'c10ud' (c10ud)]

I installed Quantal's theme and theme engine in Precise and i cannot reproduce the issue anymore.

However with Precise's stock theme the segfault can still be reproduced.

[Riccardo 'c10ud' (c10ud)]

Cimi (thanks!) suggests searching for "transition" in gtk-widgets.css and make some tests with Precise-stock theme.
He says it's probably a bug in gtk regarding that thing.

For comparison, here's the relevant part in Quantal's theme:
$ cat /usr/share/themes/Ambiance/gtk-3.0/gtk-widgets.css | grep transition
     transition: 750ms linear loop;

[Riccardo 'c10ud' (c10ud)]

with Precise's light-themes package (reproducible crash):

$ cat /usr/share/themes/Ambiance/gtk-3.0/gtk-widgets.css | grep transition
    transition: 100ms ease-in-out;
     transition: 750ms linear loop;
    transition: 0ms ease-in-out;
    transition: 0ms ease-in-out;

[Riccardo 'c10ud' (c10ud)]

commenting out:
     /*transition: 100ms ease-in-out;*/

appears to fix (or workaround the issue).
The relevant part:

GtkComboBox,
.button {
    background-image: -gtk-gradient (linear, left top, left bottom,
                                     from (shade (@button_bg_color, 1.1)),
                                     to (shade (@button_bg_color, 0.9)));
    border-radius: 3px;
    border-style: solid;

    color: @fg_color;
    text-shadow: 0 1 alpha (shade (@button_bg_color, 1.25), 0.4);

    /*transition: 100ms ease-in-out;*/

    -unico-border-gradient: -gtk-gradient (linear, left top, left bottom,
                                           from (shade (@button_bg_color, 0.85)),
                                           to (shade (@button_bg_color, 0.67)));
    -unico-glow-color: shade (@button_bg_color, 1.14);
    -unico-glow-radius: 6;
    -unico-inner-stroke-gradient: -gtk-gradient (linear, left top, left bottom,
                                                 from (shade (@button_bg_color, 1.16)),
                                                 to (shade (@button_bg_color, 1.015)));
    -unico-inner-stroke-width: 1px;
}

[Riccardo 'c10ud' (c10ud)]

Needs to be tested in Quantal - add this to your gtk-widgets.css:

GtkComboBox,
.button {
    transition: 100ms ease-in-out;
}

And see if issue persists

[Riccardo 'c10ud' (c10ud)]

    transition: 0ms ease-in-out;
    transition: 0ms ease-in-out;

Needs to be commented out as well.

[Riccardo 'c10ud' (c10ud)]

Ok, since I wanted to run gtk3 in Precise, I uploaded a modified version of light-themes in the emesene-stable PPA.

https://launchpad.net/~emesene-team/+archive/emesene-stable/+build/3959490

This version differs from the precise-proposed one: it removes the transition properties that make the program crash.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.
Ubuntu 12.04 (precise) reached end-of-life on April 28, 2017.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test.