Package: ifupdown-ng
Version: 0.12.1-7
Severity: normal
Tags: patch

Dear Maintainer,

I recently upgraded a bookworm to trixie. However, after the reboot, the system
did not bring up any network interfaces apart from lo. (This being a headless
system managed over the network was a minor inconveniency.)

I believe the following is what happened.

The system is configured NOT to install Recommends, i.e. it has 
APT::Install-Recommends "false";

The system (initially installed as bookworm 1.5 years ago) is set up to use 
ifupdown-ng to bring up its nerwork interfaces.

The apt-get dist-upgrade went smoothly - as always.

However, after boot, the only network interface that was brought up was lo,
leaving the system unreachable (except via BMC).

The obvious expectation was that the interfaces configured in

/etc/network/interfaces.d (sourced by /etc/network/interfaces)

would be brought up and the system reachable.

I believe this happened because of the two conditions above: ifupdown-ng manages
network and apt does not install recommends: there is a mysterious entry in
ifupdown-ng's changelog from 2023:

"Fix upgrade path from stable not installing ifupdown compat"

which - in hindsight - I presume meant that ifupdown-ng-compat package was 
created
and added as Recommends to ifupdown-ng. You see where this goes: not installing
Recommnds leaves the system without ifupdown-ng-compat and hence without 
networking.service, hence nothing tries to bring the interfaces up.

While this is probably a rather uncommon corner case, I still believe this is a 
"bug"
that needs to be addressed, but how? I agree Recommends is appropriate instead 
of 
Depends, so I guess the only remaining option is a note in Trixie (and maybe 
also in
Forky) upgrade/release notes chapter 5 (or maybe 4.5?), so at least other 
admins of
headless systems using ifupdown-ng have a chance of noticing this before 
rebooting.

Cheers,
Juha

P.S. After installing ifupdown-ng-compat, the networking.service was left in a
disabled state - I have no opinion of whether that's better or worse than 
enabling
it, but this should also be mentioned in whatever note is written about this: 
just
installing the package is not sufficient.

-- System Information:
Debian Release: 13.1
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 6.12.43+deb13-amd64 (SMP w/32 CPU threads; PREEMPT)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, 
TAINT_UNSIGNED_MODULE
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), 
LANGUAGE=en_GB:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages ifupdown-ng depends on:
ii  adduser   3.152
ii  iproute2  6.15.0-1
ii  libbsd0   0.12.2-2
ii  libc6     2.41-12

Versions of packages ifupdown-ng recommends:
ii  ifupdown-ng-compat             0.12.1-7
ii  isc-dhcp-client [dhcp-client]  4.4.3-P1-8
pn  rdnssd                         <none>

Versions of packages ifupdown-ng suggests:
pn  ppp  <none>

-- no debconf information

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