Re: Missing virtual provides on postgresql-9.4 deb

On Wed, Jun 24, 2015 at 5:02 AM, Christoph Berg <cb(at)df7cb(dot)de> wrote:

> I'm not saying we can't change this, though there's some reason behind
> the way it currently is. Martin, do you remember if that "Provides:"
> mismatch between server and client was intended, or did we just forget
> that? Should we rather remove it from the client packages as well?
>

My familiarity with virtual provides is so that any packages with have a
non-versioned dependency on postgres, will be satisfied by whatever version
of postgres* installed. It's commonly used when co-installing packages of
the same name (different versions). Dependencies that require a specific
version should do so in their "Depends" statement.

This convention is already used in the postgresql-9.4 RPM packages, as seen
below.

# rpm -q --provides postgresql94-server
> config(postgresql94-server) = 9.4.4-1PGDG.rhel7
> postgresql-server
> postgresql94-server = 9.4.4-1PGDG.rhel7
> postgresql94-server(x86-64) = 9.4.4-1PGDG.rhel7
>

On RPM based systems, this allows one to install postgresql94-server, and
later remove postgresql-server. The virtual provides ensure any packages
with a postgresql-server requirement remain on the system, after
`postgresql-server` has been removed (since the dependency is met by
postgresql94-server).

Thanks,
James