81c0cf0834
Reading upon the history of this code branch (commits 6891ce95dce and 7a4c808e43d4 are most relevant), it seems this code is meant to synchronize Mutter focus state taking the Xserver state as true. That is, if Mutter tried to change the focus but something truncated that action, Mutter focus will be changed to be in sync with the Xserver again. This sounds backwards in a Wayland session. Mutter focus should be the canonical source, and not second-guessed from the current Xserver focus window. These race conditions might still apply between X11 clients, so make these paths only apply in that case. An example of this breaking can be reproduced with a Spotify and Firefox window, moving the focus from the first to the second by going to the GNOME Shell overview in between, and clicking the Firefox window from there. The Firefox window will be raised, but refuse to take focus. It's unclear what made this an issue recently, perhaps commit 0e6395d9328 since the now possibly ignored XI_FocusIn/Out events affect this accounting of the Xserver focused window. Anyhow it sounds better to ignore these paths for Wayland/native altogether. Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2841>
Mutter
Mutter is a Wayland display server and X11 window manager and compositor library.
When used as a Wayland display server, it runs on top of KMS and libinput. It implements the compositor side of the Wayland core protocol as well as various protocol extensions. It also has functionality related to running X11 applications using Xwayland.
When used on top of Xorg it acts as a X11 window manager and compositing manager.
It contains functionality related to, among other things, window management, window compositing, focus tracking, workspace management, keybindings and monitor configuration.
Internally it uses a fork of Cogl, a hardware acceleration abstraction library used to simplify usage of OpenGL pipelines, as well as a fork of Clutter, a scene graph and user interface toolkit.
Mutter is used by, for example, GNOME Shell, the GNOME core user interface, and by Gala, elementary OS's window manager. It can also be run standalone, using the command "mutter", but just running plain mutter is only intended for debugging purposes.
Contributing
To contribute, open merge requests at https://gitlab.gnome.org/GNOME/mutter.
It can be useful to look at the documentation available at the Wiki.
The API documentation is available at:
- Meta: https://gnome.pages.gitlab.gnome.org/mutter/meta/
- Clutter: https://gnome.pages.gitlab.gnome.org/mutter/clutter/
- Cally: https://gnome.pages.gitlab.gnome.org/mutter/cally/
- Cogl: https://gnome.pages.gitlab.gnome.org/mutter/cogl/
- CoglPango: https://gnome.pages.gitlab.gnome.org/mutter/cogl-pango/
Coding style and conventions
See HACKING.md.
Git messages
Commit messages should follow the GNOME commit message
guidelines. We require an URL
to either an issue or a merge request in each commit. Try to always prefix
commit subjects with a relevant topic, such as compositor: or
clutter/actor:, and it's always better to write too much in the commit
message body than too little.
Default branch
The default development branch is main. If you still have a local
checkout under the old name, use:
git checkout master
git branch -m master main
git fetch
git branch --unset-upstream
git branch -u origin/main
git symbolic-ref refs/remotes/origin/HEAD refs/remotes/origin/main
License
Mutter is distributed under the terms of the GNU General Public License, version 2 or later. See the COPYING file for detalis.