Bug#549910: debian-policy: Specify requirement in terms of upgradeability, interface stability

["Giacomo A. Catenazzi" <cate@debian.org>]

Raphaël Hertzog wrote:
> Package: debian-policy
> Version: 3.8.3.0
> Severity: wishlist
>
> We have some unwritten packaging rules and it would be good to write them
> down even if some of them appear to be obvious to most of us. I think in
> particular to stuff like:
>
> - a package must at least be upgradable from one stable release to the next:
>   - transitional packages are required when the software is renamed
>   - {pre,post}{inst,rm} snippets dealing with upgrade issues must be kept
>     for at least one release (but it's better to keep them for 2-3
>     releases)

I agree

> - a package must provide some interface stability (names of programs,
>   ABI/API of libraries, location of data files, etc.) when other packages
>   depend on it. In that case,  any change must be coordinated and
>   appropriate dependencies must be added. It should give examples of
>   Breaks:, bumped Depends when an change is made in a non-backwards
>   compatible way, temporary compatibility symlinks, etc.

I find difficult to implement it in policy in a clear way. We already have
nearly the same requirement for ABI/API in libraries: the package name must
contain the SOVERSION.
If we add such requirement, I would change chapter 8 from
"Shared libraries" into "Shared libraries and common files" and adding
a general stability suggestion.

BTW I find no reference in policy about the NEWS.Debian file. It would
nice to require to document (at last for one stable release) all (also
user visibe API/ABI) incompatibilities in such files.

ciao
	cate