I am forwarding response from Alex.

-------- Původní zpráva --------
Předmět: Re: Provides: rubygem(name) automation
Datum: Wed, 27 Apr 2011 12:14:15 +0300
Od: Alexander Kurtakov <akurtako@redhat.com>
Společnost: Red Hat Inc.
Komu: Vít Ondruch <vondruch@redhat.com>
Kopie: ruby-sig@lists.fedoraproject.org


On 12:07:29 PM Wednesday, April 27, 2011 Vít Ondruch wrote:
> Dne 26.4.2011 23:55, Mo Morsi napsal(a):
> > On 04/21/2011 05:29 AM, Vít Ondruch wrote:
> >> Hello everybody,
> >> 
> >> Today I was contacted by Aleksandar Kurtakov and he proposed, that he
> >> would help us to autogenerate the RPM provides. This functionality is
> >> allowed by RPM 4.9 [1], it means for F15+. This would help Aleksandar
> >> for better RubyGem integration into rpmstubby [2] and at the end into
> >> Eclipse Fedora Packager [3].
> >> 
> >> Basically we would need to place rubygem.attr (see [4] for maven
> >> example) file into /usr/lib/rpm/fileattr and script which would generate
> >> the provides (see [5] for maven example). Since this files are required
> >> during build, they should be probably part of rubygems package, although
> >> it has some cavities.
> >> 
> >> In theory, this approach could also be used to generate Requires and
> >> BuildRequires from gem spec file.
> >> 
> >> 
> >> Any thought are highly appreciate.
> >> 
> >> 
> >> Vit
> > 
> > Looked this over and I like the direction this is going, bringing more
> > automated dependency checking and analysis into RPM is a good idea, and
> > in conjunction with some additional Fedora policies (this is acceptable
> > to start integrating into Fedora correct?), it seems that alot of
> > developer effort would be alleviated.
> > 
> > 
> > The biggest concern that I have at this point is the dependency version
> > analysis, especially with the Ruby packages.
> > 
> > For gems we can parse version information out of the gemspec, for
> > bundler we can parse it out of the Gemfile, but we'll probably run into
> > some cases which this will not be enough, whether the dependencies are
> > not (or cannot) be fully represented or where there is no dependency
> > list per-se (in which case we might be able to get away with parsing the
> > 'require's, there is a few ideas on how to do this here [1]).
> > 
> > 
> > One additional question I had is how easy it would be to override the
> > dependency generator. Lets say there is a mistake in the generator or a
> > use case that it does not work for and/or generated incorrect
> > dependencies for, will ruby packagers have to wait until that is
> > resolved to submit their packages. Will explicit dependencies in the
> > spec override the dependency checker?

* You can disable the dependency generator entirely. See 
http://rpm.org/wiki/PackagerDocs/DependencyGenerator
* You can add additional provides manually and let the automatically generated 
provides just stay as is. It's not a problem if your manual provide is the 
same as the automatically generated one.
You would not have to wait because everything you put in the spec file manually 
will simply be there no matter what the dependency generator has done.

> 
> In my understanding, there will be always both dependencies listed. One
> set of dependencies will be generated automatically by some dependency
> generator and there will second set of dependencies entered explicitly
> in .spec file.

That's not exactly true. Ideally after reaching critical mass with automated 
provides/requires generated you will not need to add anything manually in most 
cases unless there is some obscure case.

P.S. I'm not subscribed so the moderator should approve it or someone resend.

Hope that helps,
Alex


> 
> >    -Mo
> > 
> > [1]
> > http://rubyforge.org/pipermail/gem2rpm-devel/2010-September/000008.html
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