CentOS - Jul 2017 - How does yum decide when 2 packages meet a dependency?

On Fri, 21 Jul 2017, Matthew Miller wrote:
> On Fri, Jul 21, 2017 at 04:19:20PM +0100, Phil Perry wrote:
>> Say a package has a dependency for libfoo.so.1, and 2 (or more)
>> packages provide libfoo.so.1, how does yum decide which package to
>> install to meet the dependency?
>
> It has a series of heuristics:
>
> http://yum.baseurl.org/wiki/CompareProviders
That's fabulous.  You mean Phil could have fixed my issue by renaming the
package priiiiiimus so that the name was longer than mesa-libGL ;)

jh

On Fri, Jul 21, 2017 at 05:00:35PM +0100, John Hodrien
wrote:
> >>Say a package has a dependency for libfoo.so.1, and 2 (or more)
> >>packages provide libfoo.so.1, how does yum decide which package to
> >>install to meet the dependency?
> >It has a series of heuristics:
> >http://yum.baseurl.org/wiki/CompareProviders
> That's fabulous.  You mean Phil could have fixed my issue by renaming
the
> package priiiiiimus so that the name was longer than mesa-libGL ;)
Tragically possible. :)


-- 
Matthew Miller
<mattdm at fedoraproject.org>
Fedora Project Leader

On 21/07/17 17:10, Matthew Miller wrote:
> On Fri, Jul 21, 2017 at 05:00:35PM +0100, John Hodrien wrote:
>>>> Say a package has a dependency for libfoo.so.1, and 2 (or more)
>>>> packages provide libfoo.so.1, how does yum decide which package
to
>>>> install to meet the dependency?
>>> It has a series of heuristics:
>>> http://yum.baseurl.org/wiki/CompareProviders
Many thanks Matthew, that's a great overview.
>> That's fabulous.  You mean Phil could have fixed my issue by
renaming the
>> package priiiiiimus so that the name was longer than mesa-libGL ;)
> 
> Tragically possible. :)
> 
> 
In this case, working through the logic, it would appear that primus 
probably won the battle on the basis of pulling in fewer deps than 
mesa-libGL, but what else is already installed on the system would 
clearly have an effect here.

Still, nice to know the logic involved.