Bug#1075614: Please cancel NMU of v-sim + help needed for autopkgtest of new upstream version

[Simon McVittie]

On Thu, 27 Feb 2025 at 11:02:46 +0000, Simon McVittie wrote:
> On Thu, 27 Feb 2025 at 10:49:04 +0100, Andreas Tille wrote:
> > gi.RepositoryError: Typelib file for namespace 'xlib', version '2.0' not found
> 
> Is the new upstream version perhaps not generating that dependency?

>From the build logs and history on Salsa, I think this is a regression in
https://salsa.debian.org/science-team/v-sim/-/commit/ec9b6f88c88eb2b5e44b13bf0f5bd1355a97f863
"Switch from cdbs to dh" rather than anything to do with the new upstream
version specifically.

Now that this package is no longer using /usr/share/cdbs/1/class/gnome.mk,
there is no longer anything to say that it should use the "gir"
debhelper sequence or run dh_girepository, so... it doesn't. As a result,
the ${gir:Depends} and ${gir:Provides} are not populated and the
dependencies are missing.

Please add "Build-Depends: dh-sequence-gir" if you prefer the declarative
style (I would personally recommend this), or run dh as "dh $@ --with gir"
if you prefer the imperative style.

Looking at the build log from Salsa-CI, you probably also want
"Build-Depends: dh-sequence-python3", or "dh $@ --with gir,python3".

A way to avoid this problem in future would be: when you are doing major
build-system surgery, I would suggest doing a build with the old build
system first and moving it to a reference directory, then doing a build
with the proposed change, running debdiff on the two builds, and repeating
until all the differences look intentional or non-problematic.
In this case I think you would see that all the Depends for gir1.2-*
packages would have disappeared, and that's what is causing the autopkgtest
failure.

Another way to avoid this problem in future would be to check the build log
and see whether the warnings issued by dpkg-gencontrol can be explained
away as not being a real problem. In this case, the warnings that tell you
you're missing some dh sequences are:

    dpkg-gencontrol: warning: Depends field of package python3-v-sim: substitution variable ${python3:Depends} used, but is not defined
    dpkg-gencontrol: warning: Depends field of package gir1.2-v-sim-1.0: substitution variable ${gir:Depends} used, but is not defined

I hope this helps,
    smcv