Status of weak dependencies support in Fedora 21+

[Jan Zelený]

On 10. 11. 2014 at 10:04:53, Michal Sekletar wrote:
> On Sat, Nov 08, 2014 at 09:54:35PM +0400, Peter Lemenkov wrote:
> > Hello All!
> > RPM shipped with Fedora 21+ has support for weak dependencies. What's
> > the current status of that feature? Is it ok to start using them
> > (building RPM with Recommends/Suggests tags)?
> 
> I don't think it is ok to start using them for now. We don't have any
> packaging guidelines on their usage.

On the other hand, writing down guidelines without any prior experience might 
do more damage than good, that's why I would like Fedora maintainers to give 
this a shot. We plan to gather some feedback on the Developer Conference [1] 
to tune up the guidelines.

However, what I'm not sure about is whether it's already possible to build 
weak-deps enhanced rpms in Fedora, has someone tested that? I've heard it's 
possible in COPR but I'm not sure about koji.

> > I have a real-world example where I'd like to mark a dependency as
> > Suggests instead of Requires and want to know if dnf is ready to
> > process it?
> 
> I played with Recommends in one case and it actually worked as expected.
> Even package uninstalls and updates honored the dependency semantics as
> expected. However I think it is because libsolv's logic and not some
> explicit handling in dnf.

Yeah, that's the sweet part. There needs to be some level of support in the 
layers above but ultimately libsolv is the key part when it comes to weak 
deps.

[1] http://devconf.cz/

Thanks
Jan