Exact dependencies and Architecture: all packages

[Colin Watson <cjwatson@debian.org>]

I just found myself unable to do a binary-only NMU because an
Architecture: all binary package from that source package had an exact
dependency, generated with (= ${Source-Version}), on an Architecture:
any binary package from the same source package. Whatever way I did the
upload, it would either break the architecture I was planning to upload
on or else all other architectures. As a result, a sourceful upload will
be required. See #227618.

I think that we should recommend against using (= ${Source-Version})
dependencies from Architecture: all to Architecture: any packages or
vice versa. They're OK between architecture-independent packages and
between architecture-dependent packages, but mixing those causes
trouble.

I can't immediately think of an easy way to scan the archive for this
problem, unfortunately.

-- 
Colin Watson                                  [cjwatson@flatline.org.uk]