Bug#1084133: mutter: FTBFS on armhf: Directory "/tmp/.X11-unix" is not writable

[Aurelien Jarno]

Hi,

On 2024-10-05 14:19, Simon McVittie wrote:
> Source: mutter
> Version: 47.0-2
> Severity: serious
> Tags: ftbfs
> Justification: fails to build from source (but built successfully in the past)
> X-Debbugs-Cc: debian-arm at lists.debian.org, armhf at buildd.debian.org
> User: debian-arm at lists.debian.org
> Usertags: armhf
> Control: block 1081519 by -1
> 
> The recent upload of mutter in unstable FTBFS on multiple armhf buildds:
> arm-ubc-01, arm-conova-03, arm-ubc-05. Interestingly, the arm64 build on
> one of the same buildds (arm-conova-03) was successful.
> 
> The error message suggests that there might be a problem with the
> chroot/container, or possibly with the host /tmp being shared with it:
> 
> > Bail out! libmutter-FATAL-ERROR: Failed to start X Wayland: Directory "/tmp/.X11-unix" is not writable
> 
> Please could a buildd operator check whether something is not working
> as intended on these buildds?

Everything is fine on the buildds side. Both arm64 and armhf chroots on
the above buildds have an empty 1777 root:root /tmp directory.

I defer further analysis to the armhf porters.

> Ideally, mutter's build-dependencies would ensure that /tmp/.X11-unix is
> created with its canonical ownership and permissions (1777 root:root),
> but invocation of /etc/init.d/x11-common is suppressed in a chroot, and
> systemd's /usr/lib/tmpfiles.d/x11.conf only creates /tmp/.X11-unix during
> boot (and not when systemd is installed into a running system). Possibly
> this directory is sufficiently special that schroot and unshare ought
> to ensure its presence as an empty directory with the correct permissions
> during chroot setup, but that can be a separate feature request.

Well if you package needs that directory, why not create it before
running the tests?

I don't think it's reasonable for sbuild to ensure random directories
are available in the chroot. Anyway the build daemons are using sbuild,
so if you really believe this is the right place to fix that, please
report it to the sbuild package instead.

> The affected buildds seem to be using schroot, as opposed to unshare.
> I don't know precisely how it is configured (/tmp from the host, or
> /tmp part of the chroot, or what).

Chroots are created identically in schroot and unshare mode. /tmp is
part of the chroot, and not shared with the host.

Regards
Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien at aurel32.net                     http://aurel32.net