Re: [gentoo-user] emerge conflict

[Alan McKinnon]

On Friday 13 August 2010 16:04:53 Frank Schwidom wrote:
> Hi
>
> i get the error:
>
> {
> !!! Multiple package instances within a single package slot have been
> pulled
> !!! into the dependency graph, resulting in a slot conflict:
>
> media-libs/libpng:0
>
>   ('ebuild', '/', 'media-libs/libpng-1.4.3', 'merge') pulled in by
>
>     >=media-libs/libpng-1.2.43-r2:0 required by ('ebuild', '/',
>     >'x11-libs/cairo-1.8.10', 'merge')
>     >=media-libs/libpng-1.4 required by ('ebuild', '/',
>     >'x11-libs/gtk+-2.20.1-r1', 'merge')
>
>     (and 27 more)
> }
>
> And i wonder that it seems not to be possible to install both libs
> (libpng-1.2.43-r2:0, libpng-1.4) in the same time. Linux is actually
> able to manage this by the lib-version and links.

You have misread the portage output. It does not say it wants those versions. 
It says this:

  >=media-libs/libpng-1.2.43-r2:0
  >=media-libs/libpng-1.4

Note the greater than or equal to.

The limiting factor to multiple versions is not Linux, it is portage. Portage 
will not co-install two versions in the same SLOT.

> Did i have overseen any gentoo switch that makes is possible? Or is
> there any other option?

This whole libpng mess was a right royal fuck up several months ago. I forget 
the specifics but IIRC a decent solution was

emerge -C libpng
emerge libpng
revdep-rebuild

The last step takes some time to complete, there is a lot of fall-out to deal 
with. 

As you are only hitting this now, I assume you have a stable system and are 
not using the masked versions of portage. @preserved-rebuild would save you 
lots of pain, but that feature is not available in stable versions of portage.

For more info, check the archives. There is more mail there about this than 
you could ever possibly want to read.

-- 
alan dot mckinnon at gmail dot com