gtk-window-decorator crashed when windows controls are on the left and GDK_SCALE=2

[Martin Wimpress ]

On Ubuntu MATE 17.10 daily I am experimenting with GDK scaling. I have exported the following in to the XSession via /etc/X11/Xsession.d

  GDK_SCALE=2
  GDK_DPI_SCALE=0.5

MATE Tweak can be used to switch between window managers and also select if windows controls are displayed on the left or the right.

  * When GDK scaling is 1 Compiz works correctly regardless of window control position.
  * When GDK scaling is active and window controls are on the right switching to Compiz works correctly.
  * When GDK scaling is active and window controls are on the left switching to Compiz causes it to segfault with the following error:

(gtk-window-decorator:2990): libmetacity-ERROR **: Could not find a button to strip. n_left = 1 n_right = -1

When MATE Tweak switches the window control positions this is what it uses:

  * Left: "close,minimize,maximize:menu"
  * Right: "menu:minimize,maximize,close"

ProblemType: Crash
DistroRelease: Ubuntu 17.10
Package: compiz-gnome 1:0.9.13.1+17.10.20170704-0ubuntu1
ProcVersionSignature: Ubuntu 4.11.0-10.15-generic 4.11.8
Uname: Linux 4.11.0-10-generic x86_64
ApportVersion: 2.20.5-0ubuntu5
Architecture: amd64
CurrentDesktop: MATE
Date: Tue Jul 18 14:22:39 2017
ExecutablePath: /usr/bin/gtk-window-decorator
InstallationDate: Installed on 2017-06-10 (37 days ago)
InstallationMedia: Ubuntu-MATE 17.10 "Artful Aardvark" - Alpha amd64 (20170606)
ProcCmdline: /usr/bin/gtk-window-decorator
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_GB.UTF-8
 SHELL=/usr/bin/fish
Signal: 5
SourcePackage: compiz
StacktraceTop:
 () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
 g_log_writer_default () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
 g_log_structured_array () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
 g_log_structured () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
 () at /usr/lib/x86_64-linux-gnu/libmetacity.so.1
Title: gtk-window-decorator crashed with signal 5
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip libvirt lpadmin plugdev sambashare sudo

[Apport retracing service (apport)]

StacktraceTop:
 _g_log_abort () from /tmp/apport_sandbox_e_CrVT/lib/x86_64-linux-gnu/libglib-2.0.so.0
 g_log_writer_default () from /tmp/apport_sandbox_e_CrVT/lib/x86_64-linux-gnu/libglib-2.0.so.0
 g_log_structured_array () from /tmp/apport_sandbox_e_CrVT/lib/x86_64-linux-gnu/libglib-2.0.so.0
 g_log_structured () from /tmp/apport_sandbox_e_CrVT/lib/x86_64-linux-gnu/libglib-2.0.so.0
 meta_theme_metacity_calc_geometry () from /tmp/apport_sandbox_e_CrVT/usr/lib/x86_64-linux-gnu/libmetacity.so.1

[Alberts Muktupāvels (muktupavels)]

https://git.gnome.org/browse/metacity/commit/?id=0baa5d7bdeedab5b5cebc29c762ecb34fca22f7b

Might be related to crash, if so than this bug might be fixed with libmetacity 3.26.0...

[Martin Wimpress  (flexiondotorg)]

Confirmed fixed on Ubuntu MATE 18.04 (daily). Thank you!