How to patch a debian package?

Question

I have Debian stable and I have found some weird bug which was already fix.

The fix were merged into the stable branch which version was gnome-settings-daemon 3.32.1 but I have gnome-settings-daemon 3.30.2-3 So, how can I use the patch without breaking my system? I have to install from where? Backports?

I check versions with apt but I don't see any useful here:

/home/user-> apt-cache policy gnome-settings-daemon
gnome-settings-daemon:
  Installed: 3.30.2-3
  Candidate: 3.30.2-3
  Version table:
 *** 3.30.2-3 500
        500 http://deb.debian.org/debian buster/main amd64 Packages
        100 /var/lib/dpkg/status

Thanks in advance!

Answer 1

backports.debian.org does not seem to include the package gnome-settings-daemon for buster.

The testing branch currently has version 3.38.1-2, which is quite a bit newer than what you need.

The recommended way would be to backport the patch yourself.

You would have to:

• install any development packages required to build gnome-settings-daemon:

sudo apt-get build-dep gnome-settings-daemon

• get the source code for gnome-settings-daemon

apt-get source gnome-settings-daemon

• apply the patch

cd gnome-settings-daemon-3.30.2/
curl 'https://gitlab.gnome.org/GNOME/gnome-settings-daemon/-/commit/cea632bf682760e80654df19cfef6206efca868a.diff' | patch -p1

• document the addition of the patch into the package changelog (technically you could omit this if you're only using the package for yourself, but it would be a good to make this a habit if you plan to become a package maintainer)

dpkg-source --commit  # this will ask you to write a changelog entry

• build the binary package(s):

dpkg-buildpackage -rfakeroot

• and finally install the resulting binary packages:

cd ..
sudo dpkg -i gnome-settings-daemon_3.30.2-3_amd64.deb gnome-settings-daemon-common_3.30.2-3_all.deb

• If you wish to make the change effective without logging out, you'll need to kill any existing gsd-media-keys process so that gnome-settings-daemon will restart it using the new binary:

killall gsd-media-keys

Answer 2

According to the Debian Packages page for gnome-settings-daemon, the latest version for stable (buster) is 3.30.2-3 (which you already have installed).

However, for testing (bullseye) and unstable (sid), version 3.38.1-2 is available. Thus, you could install only the missing packages from those newer releases, as described here: How to install some packages from “unstable” Debian on a computer running “stable” Debian?

Backports and compiling from source are further options (also described in the answer linked above).