non-installable in chroots without udev installed due to bad postinst file

[Gianfranco Costamagna]

[Impact]
packages using rfkill in build-dependencies are not installable.

[Test Case]
Install rfkill in a chroot without udev installed

Unpacking rfkill (0.5-1ubuntu3) ...
Setting up rfkill (0.5-1ubuntu3) ...
/var/lib/dpkg/info/rfkill.postinst: 5: /var/lib/dpkg/info/rfkill.postinst: udevadm: not found
dpkg: error processing package rfkill (--configure):
 subprocess installed post-installation script returned error exit status 127

[Regression Potential]
* None, udev is already installed in user machines

[Gianfranco Costamagna (costamagnagianfranco)]

Artful is mostly EOL
Package is removed in Bionic. I consider enough fixing Xenial only

[Robie Basak (racb)]

Do we really need to add a dependency here? Why not silently do nothing if udevadm isn't available? That'd fix your chroot case, right?

[Gianfranco Costamagna (costamagnagianfranco)]

the problem is: it already has a runtime dependency on systemd, why doesn't it automagically add udev?

[Gianfranco Costamagna (costamagnagianfranco)]

also changing the line to:
    udevadm trigger --subsystem-match=rfkill || true

fixes the issue, giving a warning during installation

[Robie Basak (racb)]

Some discussion here: https://irclogs.ubuntu.com/2018/06/18/%23ubuntu-release.html#t16:00

[Gianfranco Costamagna (costamagnagianfranco)]

reuploaded with
command -v udevadm >/dev/null && udevadm trigger --subsystem-match=rfkill

[Gianfranco Costamagna (costamagnagianfranco)]

command -v didn't work correctly, lets go for:
if [ -x /sbin/udevadm ]; then
    udevadm trigger --subsystem-match=rfkill
fi

[Robie Basak (racb)]

Hello LocutusOfBorg, or anyone else affected,

Accepted rfkill into xenial-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/rfkill/0.5-1ubuntu3.1 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed.Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested and change the tag from verification-needed-xenial to verification-done-xenial. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-xenial. In either case, details of your testing will help us make a better decision.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance!

[Gianfranco Costamagna (costamagnagianfranco)]

Selecting previously unselected package rfkill.
(Reading database ... 12129 files and directories currently installed.)
Preparing to unpack rfkill_0.5-1ubuntu3.1_amd64.deb ...
Unpacking rfkill (0.5-1ubuntu3.1) ...
Setting up rfkill (0.5-1ubuntu3.1) ...

I like it!

[Launchpad Janitor (janitor)]

This bug was fixed in the package rfkill - 0.5-1ubuntu3.1

---------------
rfkill (0.5-1ubuntu3.1) xenial; urgency=medium

  * postinst: do not fail in case udev is not available (e.g. chroot)
    (LP: #1777476)

 -- Gianfranco Costamagna <email address hidden> Mon, 18 Jun 2018 17:53:33 +0200

[Łukasz Zemczak (sil2100)]

The verification of the Stable Release Update for rfkill has completed successfully and the package has now been released to -updates. Subsequently, the Ubuntu Stable Release Updates Team is being unsubscribed and will not receive messages about this bug report. In the event that you encounter a regression using the package from -updates please report a new bug using ubuntu-bug and tag the bug report regression-update so we can easily find any regressions.