pidgin crashed with SIGSEGV in g_type_check_instance_cast()

[GonzO]

This happens *very* predictably. Steps to reproduce:

Install Pidgin and use the libnotify plugin with Unity (5.8 at current release).

Have tabbed conversations. Attempt to close conversation window.

The window's contents "blank out" - just show the background window grey color with window borders. One must hit the "X" again to actually close the window.

After about 5 seconds, Pidgin becomes unresponsive, then goes away. Then apport takes over.

I've never seen this problem WITHOUT the libnotify plugin being active; however, without this plugin, the message indicator (blue envelope) doesn't catch any notifications from Pidgin, and that's kind of important to me.

ProblemType: Crash
DistroRelease: Ubuntu 12.04
Package: pidgin 1:2.10.2-1ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-20.32-generic-pae 3.2.12
Uname: Linux 3.2.0-20-generic-pae i686
NonfreeKernelModules: nvidia
ApportVersion: 1.95-0ubuntu1
Architecture: i386
Date: Tue Mar 27 13:17:51 2012
ExecutablePath: /usr/bin/pidgin
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta i386 (20110901)
ProcCmdline: pidgin
ProcEnviron:
 SHELL=/bin/bash
 LANG=en_US.UTF-8
SegvReason: reading unknown VMA
Signal: 11
SourcePackage: pidgin
Title: pidgin crashed with SIGSEGV in g_type_check_instance_cast()
UpgradeStatus: Upgraded to precise on 2012-03-26 (1 days ago)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare vboxsf

[GonzO (gonzo)]

Also of note: this bug is filed with the Pidgin people, but once I mentioned libnotify, they were adamant about blaming that plugin.

[Apport retracing service (apport)]

Thank you for taking the time to report this crash and helping to make this software better. This particular crash has already been reported and is a duplicate of bug #732150, so is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.

[Gleb Kozyrev (gkozyrev)]

I don't see how this is a duplicate because unlike #732150 it has specific steps to reproduce the crash and there're different ways to trigger the crash after closing a conversation window which lead to different backtraces etc.
The attached patch that removes possibly bitrotten code duplication fixes the crash for me.

[Launchpad Janitor (janitor)]

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