Optionally allow building CPC images with core (16.04) based snaps

[Thomas Bechtold]

[Impact]
Commit 245f7772bdb743547e4d2f7df2475afc0eb5ec1e aborts the build when a snap still depends on core (16.04 runtime).
That's fine for Ubuntu but the CPC team builds images which still depend on core (that will be fixed soon). So currently those CPC builds are failing.
Adding an option to allow those builds will fix the problem.

[Test Plan]
The bug can be reproduced with:

$ ./scripts/ubuntu-bartender/ubuntu-bartender --hook-extras-dir ~/devel/canonical/cloudware/cpc_packaging.extra --livecd-rootfs-branch ubuntu/focal --livecd-rootfs-dir ~/devel/livecd-rootfs/ -- --series focal --project ubuntu-cpc --image-target ec2-anbox

So getting this command passing validated that the bug is fixed

[Where problems could occur]
Other builds could get broken due to this change but it's unlikely because the change is relatively small and the change is tested.

[Launchpad Janitor (janitor)]

This bug was fixed in the package livecd-rootfs - 2.759

---------------
livecd-rootfs (2.759) jammy; urgency=medium

  * Optionally (when ALLOW_CORE_SNAP env var is set) allow to install core
    snap. Still needed by some CPC projects. (LP: #1964303)

 -- Thomas Bechtold <email address hidden> Fri, 04 Mar 2022 14:00:16 +0100

[Łukasz Zemczak (sil2100)]

Any reason why the livecd-rootfs in the impish queue did not include this fix, but the one in focal does?

[Thomas Bechtold (toabctl)]

Because impish did not receive the commit that broke our build.

[Łukasz Zemczak (sil2100)]

Ok, so in that case this should be marked as Invalid for impish. Doing that now.

[Łukasz Zemczak (sil2100)]

Hello Thomas, or anyone else affected,

Accepted livecd-rootfs into focal-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/livecd-rootfs/2.664.41 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, what testing has been performed on the package and change the tag from verification-needed-focal to verification-done-focal. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-focal. In either case, without details of your testing we will not be able to proceed.

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

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Thomas Bechtold (toabctl)]

I did a testbuild with bartender and it works.
But OTOH, this patch is no longer needed given that the Anbox team did update their snaps to be based on core20.

[Brian Murray (brian-murray)]

Given that this update is included with another one let's go ahead and accept it but it would be good to remove this commit from the focal branch:

https://git.launchpad.net/livecd-rootfs/commit/?id=55dad01adcc44d9e958668ecc484c3d5b35fc3d3

[Launchpad Janitor (janitor)]

This bug was fixed in the package livecd-rootfs - 2.664.41

---------------
livecd-rootfs (2.664.41) focal; urgency=medium

  [ Ivan Kapelyukhin ]
  * Split UEFI image out of `disk-image` series file into
    `disk-image-uefi`. (LP: #1961760)

  [ Thomas Bechtold ]
  * Optionally (when ALLOW_CORE_SNAP env var is set) allow to install
    core snap. Still needed by some CPC projects. (LP: #1964303)

 -- Thomas Bechtold <email address hidden> Fri, 04 Mar 2022 14:00:16 +0100

[Brian Murray (brian-murray)]

The verification of the Stable Release Update for livecd-rootfs has completed successfully and the package is now being 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.