yum, and 2 packages that provide the same thing

[Stephen Warren]

On Fri, April 18, 2008 7:02 am, Rex Dieter wrote:
> Stephen Warren wrote:
>
>> Well, the obsoletes tag is required so that unison213 and unison227
>> obsolete the old unison package, and hence replace it on yum update.
>
> Imo,
>
> Better to choose *1* of the new unison pkgs to Obsoletes the old one,
> using
> something like:
> Obsoletes: unison < %{version}-%{release}
> Provides:  unison = %{version]-%{release}
> presumably, putting this into the newer, unison227.

That wouldn't have worked, because then one could:

yum install unison213

and yum wouldn't know to remove the existing unison, and since they share
paths, things would break (unison213 ships /usr/bin/unison-2.13, unison227
ships /usr/bin/unison-2.27, and both use alternatives to manage
/usr/bin/unison, which the original unison shipped)

> Better *yet* would've been to make unison213 only, and make the pkg
> unison = version 227

That was rejected because if a new version of unison comes out, the unison
package would then suddenly change versions, potentially breaking
everyone's installation (like when unison switched from 2.13.x to 2.27.x).