[Rpm-maint] RPM Obsoletes unversioned Provides too eagerly

[Fernando Nasser]

Michael Schroeder wrote:
> On Mon, Feb 26, 2007 at 09:51:14AM -0500, Fernando Nasser wrote:
>> Accordingly to Jeff the behavior was "broken" when someone changed it to 
>> dislodge packages based on virtual provides.
>>
>> Using your own argument, lets either revert that change or improve it.
> 
> IMHO Jeff talked about the Name -> Provides change, i.e. that rpm
> searches the provides list to obsolete packages. You talk about
> something totally different: whether a single "Provides: name"
> provides all versions or not.
> 
> Regarding the Name -> Provides change, there are some arguments
> for and against it:
> 
> + it makes obsoletes lookup consistent with requires and conflicts.
> + you can obsolete a "feature", i.e. you do not have to enumerate
>   ever packages that implements a feature if you want to obsolete
>   it.
> 
> - it surprises packagers. Say there was libOLDA a long time ago,
>   which was replaced by libB. This libB obsoletes libOLDA, and
>   libB also provides libOLD for compatibility. Then some
>   packager creates a new libC variant by copying and changing the libB
>   specfile. Now the installation of libC will remove libB.
> - Packages get also obsoleted if they provide an obsolete feature
>   among others. But maybe the other features aren't obsolete at all.
> - The current rpm implementation also looks for Provides when
>   doing the "auto-obsoletes" on the package name. I.e. package
>   A provides feature B, then B is created as a package. Now if
>   B is installed, A will automatically get obsoleted.
> 
> My feelings are that the Name -> Provides change is a bit too
> dangerous, but I also see the need for a "Feature-obsolete".
> Maybe some new syntax would have been the better way, e.g.
> 
>     Obsoletes(provides): <something>
> 


Wow, that would be great.  Totally under packager control.

I don't know how to change the parsing to set a flag (haven't looked at 
that code yet), but that flag could be passed into that subroutine we've 
been talking about to check against the proper thing, name or provides.

The only thing is that Obsoletes(provides) is how it currently works, so 
it should be the default.  One would have to say:

Obsoletes(noprovides)

to work around the unversioned provides stuff.


Regards,
Fernando