Bug#1079967: should policy and dpkg agree on allowed versions?

[Helmut Grohne <helmut@subdivi.de>]

Package: dpkg-dev,debian-policy
Severity: wishlist
X-Debbugs-Cc: pochu@debian.org

Hi Guillem and policy editors,

Emilio and me noticed that policy and dpkg have subtly different ideas
of what is a version. While man deb-version says

| The upstream-version may contain only alphanumerics (“A-Za-z0-9”)
| and the characters . + - : ~ (full stop, plus, hyphen, colon, tilde)
| and should start with a digit.

Debian policy section 5.6.1 says

| The upstream_version must contain only alphanumerics 6 and the
| characters . + - ~ (full stop, plus, hyphen, tilde) and should start
| with a digit. If there is no debian_revision then hyphens are not
| allowed.

Technically speaking, it is fine for policy to forbid things that dpkg
allows. Other distributions based on dpkg may use a different policy and
allow using multiple colons. Still is is an odd aspect and may cause
confusion. Is this difference intentional? If yes, would it make sense
to add a footnote to policy hinting that it is more restrictive than
dpkg? I also checked packages in unstable and found no packages with a
version containing two colons (i.e. all packages are policy-compliant in
this regard).

Thanks for considering

Helmut