dpkg-source warns missing XSBC-Original-Maintainer for -0ubuntu1 version

[Agathe Porte]

The XSBC-Original-Maintainer reflects who was the original maintainer before it was overridden by the vendor. However, when the vendor is the author of the first packaging and there is no such packaging in Debian, the -0ubuntu1 is used to reflect that.

However, dpkg-source warns that this field is missing but it does not make sense since the maintainer *is* the original maintainer as long as it does not exist in Debian. Expected behavior would be for the warning to not appear in this case.

Steps to reproduce:

1. Create a package with a -0ubuntu1 version in d/changelog and no XSBC-Original-Maintainer in d/control
2. Build the package using dpkg-buildpackage -us -uc
3. Watch the warning appear as dpkg-source is called from dpkg-buildpackage

I have tried to apply the following patch to dpkg-1.22.6ubuntu6.1 in Noble but the tests fail and I do not speak enough Perl to know why:

diff -Nru dpkg-1.22.6ubuntu6.1/scripts/Dpkg/Vendor/Ubuntu.pm dpkg-1.22.6ubuntu6.1+gagath/scripts/Dpkg/Vendor/Ubuntu.pm
--- dpkg-1.22.6ubuntu6.1/scripts/Dpkg/Vendor/Ubuntu.pm 2024-07-17 11:09:50.000000000 +0200
+++ dpkg-1.22.6ubuntu6.1+me/scripts/Dpkg/Vendor/Ubuntu.pm 2024-09-10 16:02:55.000000000 +0200
@@ -63,7 +63,7 @@
                    warning(g_('Version number suggests Ubuntu changes, but Maintainer: does not have Ubuntu address'));
                }
            }
- unless ($fields->{'Original-Maintainer'}) {
+ unless ($fields->{'Original-Maintainer'} or $fields->{'Version'}) ~= /0ubuntu/ {
                warning(g_('Version number suggests Ubuntu changes, but there is no XSBC-Original-Maintainer field'));
            }
         }

[Julian Andres Klode (juliank)]

That change is not correct, because there are plenty of 0ubuntu uploads of newer upstream versions that should have the field set, so you'd need to analyse debian/changelog and check if all previous uploads where Ubuntu ones to hide the warning, and I'm not sure that makes a lot of sense vs just ignoring the warning in your head.