Crash when changing file type to "Default style" in "Other"

[Vitaliy Kanev]

Steps to reproduce
------------------

1. Type some text
2. In the "Document" menu, select "File type" -> "Other" -> "Default Style"

Expected Result
---------------

No crash, document type changed

Actual result
-------------

Crash, document type not changed

Version
-------

Xubuntu 17.10.1, Mousepad 0.4.0

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: mousepad 0.4.0-4ubuntu1
ProcVersionSignature: Ubuntu 4.13.0-31.34-generic 4.13.13
Uname: Linux 4.13.0-31-generic x86_64
ApportVersion: 2.20.7-0ubuntu3.7
Architecture: amd64
CurrentDesktop: XFCE
Date: Thu Jan 25 13:30:48 2018
InstallationDate: Installed on 2018-01-18 (6 days ago)
InstallationMedia: Xubuntu 17.10 "Artful Aardvark" - Release amd64 (20180105)
SourcePackage: mousepad
UpgradeStatus: No upgrade log present (probably fresh install)

[bilka (bilka412)]

Mousepad crashes when I click on "Document" > "Type de fichier" > "Others" > "Defaults"

I guess in english it is labeled "Document" > "File Type" > "Others" > "Defaults", my system is Debian 8 with XFCE in french.

Hope this will help.

[G-matt-8 (g-matt-8)]

Confirmed, it does it here to. I have no idea what file type "Defaults" is supposed to be. Will have a look and see why it's crashing.

[Andreldm-2 (andreldm-2)]

Yeah, this crashes here when the editor is not empty.
GtkSourceView:ERROR:gtksourcecontextengine.c:5902:update_syntax: assertion failed: (state->context != NULL)
Aborted (core dumped)

Mousepad 0.4.0 GTK+2 from Arch Repo.

[G-matt-8 (g-matt-8)]

I tried looking into a bit but I haven't yet installed the sources for the GtkSourceView version on my machine.

I wonder if "Defaults" is some weird file type we should just skip/hide/disable it? I don't see it in Gedit's file type selection menu.

[Andreldm-2 (andreldm-2)]

I'm taking a look at this, so far this is where the crash happens:

GTK2:
https://github.com/GNOME/gtksourceview/blob/gnome-2-30/gtksourceview/gtksourcecontextengine.c#L5902

GTK3:
https://github.com/GNOME/gtksourceview/blob/gnome-3-16/gtksourceview/gtksourcecontextengine.c#L5468

It's weird because in GTK2 there is only "Others", but in GTK3 there is "Others->Default" and "Other->..."

[G-matt-8 (g-matt-8)]

Ahhh ... it's a special base language definition, not a real language:

https://git.gnome.org/browse/gtksourceview/tree/data/language-specs/def.lang

Judging by the `hidden=true` attribute in the XML and the existence of this function:

https://developer.gnome.org/gtksourceview/stable/GtkSourceLanguage.html#gtk-source-language-get-hidden

I guess we shouldn't be showing it, but rather checking for non-hidden filetypes to show.

[Andreldm-2 (andreldm-2)]

Created attachment 6368
Quick patch

Yep, I wrote this quick patch and it seems to work.

[Andreldm-2 (andreldm-2)]

Created attachment 6369
Improved patch

Tested on GTK2 and GTK3.

[G-matt-8 (g-matt-8)]

Thanks André, merged as http://git.xfce.org/apps/mousepad/commit/?id=720cf91f7b21864b4d3bb0ce18d96cfa719877ca

blk, if it still gives any grief, feel free to re-open.

[Launchpad Janitor (janitor)]

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