Support for MUT (Multiple Upstream Tarball) seems to be broken

[elboulangero]

Cf https://janitor.debian.net/cupboard/pkg/policykit-1/ -- we can see a lot of failures over there.

Let's look at https://janitor.debian.net/cupboard/pkg/policykit-1/2f64a9d8-be99-487e-af7e-541327338aaa/ for example.

Error is:

Status: unpack-unexpected-local-upstream-changes ()
Description: Tree has local changes: 97 files

There are changes between the upstream tarball and the non-debian/ part of the packaging repository that are not accounted for by any of the patches under debian/patches.

[...]

policykit-1-121+compat0.1/polkit-pkla-compat/test/mocklibc/src/netgroup.h
policykit-1-121+compat0.1/polkit-pkla-compat/test/mocklibc/src/pwd.c
policykit-1-121+compat0.1/polkit-pkla-compat/test/polkitbackendlocalauthoritytest.c
policykit-1-121+compat0.1/polkit-pkla-compat/test/polkitbackendlocalauthorizationstoretest.c
policykit-1-121+compat0.1/polkit-pkla-compat/test/polkittesthelper.c
policykit-1-121+compat0.1/polkit-pkla-compat/test/polkittesthelper.h
dpkg-source: error: aborting due to unexpected upstream changes, see /tmp/policykit-1_121+compat0.1-4~jan+lint1.diff.wSBH8Z
dpkg-source: info: Hint: make sure the version in debian/changelog matches the unpacked source tree
dpkg-source: info: you can integrate the local changes with dpkg-source --commit
E: Failed to package source directory /tmp/janitorwvcrpyl6/build-area/policykit-1-121+compat0.1
brz: ERROR: The build failed.

The "special thing" with this package is the use of Multiple Upstream Tarball, as can be seen in:

• https://salsa.debian.org/utopia-team/polkit/-/blob/348f020062c2bfee8025d0edf96e123790ce122f/debian/watch#L8-10
• https://salsa.debian.org/utopia-team/polkit/-/blob/348f020062c2bfee8025d0edf96e123790ce122f/debian/gbp.conf#L6

This extra component is unpacked in the directory polkit-pkla-compat, and that's what dpkg-source is complaining about. So clearly, something, somewhere, doesn't handle the MUT correctly.

Note that the Janitor page suggests me to run:

debcheckout policykit-1
cd policykit-1
lintian-brush

And that... works fine. The issue can't be reproduced this way.

NB: same error with Kali's Janitor: https://janitor.kali.org/cupboard/pkg/policykit-1/4df2618a-59c3-4eed-8221-a0e91c6cc117/

Thanks!