Hi,

Severity: minor because this is probably an exotic corner case. I'm
filing this anyway becuse it is probably easily fixed.

I'm on the adduser team. Adduser is part of the minimal install and is
therefore installed in every environment that autopkgtest is run in. In
current experimental, adduser has migrated /etc/adduser.conf to being an
dpkg-conffile. Before that, adduser.conf was kind of "managed" in
postinst.

adduser.conf suddenly becoming a dpkg-conffile causes dpkg to emit a
conffile prompt in every case of adduser <= 3.123 being updated to
adduse >= 3.125.

This also happens when the newly built adduser.deb gets installed during
autopkgtest. The autopkgtest run stalls in this case and needs manual
intervention to continue.

Is this autopkgtest's intended behavior? If not, would passing
--force-confnew to dpkg solve this issue?

This most probably only happens iff:

- the package in test is already part of the base install AND
- the package in test has recently changed a maintainer-managed
  configuration file to being a dpkg-conffile.

Since this is probably exotic, I'm holding off uploading a new version
of adduser to unstable until Friday Aug 5 to give you a chance to
reproduce this behavior. Let me know when I can upload earlier please.

I am setting Jason Franklin, my team colleague who investgated this in
depth, as Cc so that he can give additional information that I might
have forgotten.

Greetings
Marc

Control: clone -1 -2
Control: retitle -1 autopkgtest: installation stalls if newly-built deb causes a conffile prompt
Control: retitle -2 adduser: dpkg conffile prompt for adduser.conf even though unmodified
Control: severity -2 serious
Control: reassign -2 adduser 3.125

This sounds like autopkgtest has accidentally detected a genuine bug in
adduser. Packages are generally expected not to prompt a user to merge
changes to a conffile that they never actually edited: the Policy wording
is that they "must not ask unnecessary questions (particularly during
upgrades)" (§10.7.3).

piuparts detects this
(https://piuparts.debian.org/sid2experimental/conffile_prompt_error.html
lists adduser/experimental) and this class of bugs is considered to be RC.
I can reproduce this in a bullseye test VM by upgrading adduser from 3.118
(the version in bullseye) to 3.125 (from experimental), making this a very
high-visibility issue, since it would affect basically all bullseye users
when they upgrade to bookworm.

As a short-term answer, please revert this change before uploading to
unstable.

In the longer term, I'm not an expert on the finer points of conffiles,
but one solution might be to record the hashes of known unmodified
versions of adduser.conf (at least the versions in stable and testing,
ideally all versions between those endpoints), and in preinst, if
adduser.conf matches the hash corresponding to the *old-version* that
was passed to the preinst, move it out of the way so that dpkg can unpack
the new conffile over it.

If autopkgtest is going to do anything to work around unwanted conffile
prompts, a more likely answer would be to set DEBIAN_FRONTEND=noninteractive
(it already does in various places, but perhaps not this one), which will
have an effect more similar to dpkg --force-confdef --force-confold.

Perhaps we should deliberately not work around this, in order to be
able to detect this class of bug; or perhaps we should work around
it and leave piuparts to detect this class of bug instead; or perhaps
autopkgtest should work around this, but then look for /etc/**.dpkg-new
with names corresponding to files owned by a package under test, and
treat them like a failed test.

    smcv

Es gibt eine Familienspende in Höhe von 1.850.000,00 USD von Cheng Charlie
Saephan. Bitte antworten Sie für weitere Informationen. Denken Sie daran,
Ihrer Familie und den Bedürftigen in Ihrer Umgebung Gutes zu tun.

Dies ist bereits der zweite Versuch, Sie zu erreichen. Bitte antworten Sie
für weitere Details.

Es gibt eine Familienspende in Höhe von 1.850.000,00 USD von Cheng Charlie
Saephan. Bitte antworten Sie für weitere Informationen. Denken Sie daran,
Ihrer Familie und den Bedürftigen in Ihrer Umgebung Gutes zu tun.

Dies ist bereits der zweite Versuch, Sie zu erreichen. Bitte antworten Sie
für weitere Details.