Re: [gentoo-user] re: resolving blocked packages [media-video/ffmpeg-1.2:0]

[Alan McKinnon]

On 02/11/2013 21:06, Alexander Kapshuk wrote:
>>> The basic problem is a stable system with a bunch of unstable packages
>>> >> installed.
>>> >>
>>> >> The requested vlc version is ~arch, which wants a ~arch version of
>>> >> gnutls. This conflicts with other stable packages that want a stable
>>> >> version of gnutls.
>>> >>
>>> >> Mixing and matching arch and ~arch like this often causes unsolveable
>>> >> problems, especially with basic libs like gnutls used by lots of
>>> >> packages. In this specific case, I doubt very much that the problem is
>>> >> solveable. Either make the entire system ~arch or downgrade vlc to
>>> >> stable. Mixing is not recommended, not that it won't work (it often
>>> >> does), but because users so often run into these problems and devs
>>> >> usually will not help fix it. The user is thus totally on tehir own with
>>> >> this one.
>>> >>
>>> >>
>> > Ah, I wasn't aware that it wasn't a supported thing. Good points; the
>> > testing necessary to support mixed systems is more than any dev team
>> > could handle realistically. I mix and match, but only for a select few
>> > packages that simply don't have a stable version.
>> >
>> > Alex: In order to get ~arch vlc, you had to put vlc in your
>> > package.accept_keywords file. Try removing that to go back to the stable
>> > build and see if that corrects things. If not, then I agree with Alan
>> > and you should probably make the big decision of stable or testing.
>> >
> Thanks very much for your responses to my original query.
>
> What I did do prior to getting your responses was try and resolve the
> dependency conflict as shown below.
>
> (1). I added '=net-libs/gnutls-3.2.5 ~x86' and
> '=media-video/ffmpeg-1.2.4 ~x86' to package.accept_keywords:
> box0=; egrep 'gnutls|ffmpeg' /etc/portage/package.accept_keywords
> =net-libs/gnutls-3.2.5 ~x86
> =media-video/ffmpeg-1.2.4 ~x86
> (2). I then updated 'media-video/ffmpeg' to version
> 'media-video/ffmpeg-1.2.4', like so:
> emerge --ask '>media-video/ffmpeg-1.0.7'
> !!! existing preserved libs:
>>>> >>> package: media-video/ffmpeg-1.2.4
>  *  - /usr/lib/libavutil.so.51
>  *  - /usr/lib/libavutil.so.51.73.101
>  *      used by /usr/bin/mencoder (media-video/mplayer-1.1.1-r1)
>  *      used by /usr/bin/mplayer (media-video/mplayer-1.1.1-r1)
>  *      used by /usr/lib/vlc/plugins/codec/libavcodec_plugin.so
> (media-video/vlc-2.0.9)
>  *      used by /usr/lib/vlc/plugins/demux/libavformat_plugin.so
> (media-video/vlc-2.0.9)
> Use emerge @preserved-rebuild to rebuild packages using these libraries
> (3). I then pulled in the other updates:
> emerge --ask --update --deep --with-bdeps=y --newuse world
> (4). Rebuilt the preserved libs as recorded in
> /var/lib/portage/preserved_libs_registry
> emerge --ask @preserved-rebuild
>
> So far, the whole system seems to be running OK.


Yes, that is how it is done


> It did occur to me afterwards, like Alan and Daniel suggested, that
> mixing stable and unstable packages was not a good idea.


The reason it's not a good idea usually is that you get these conflicts
with dependencies. The software still runs and things still work but the
user can cause themselves lots of extra hassle to make it work.

Here, vlc depends on a gnutls version 3, which is a bit sad. I would
hope the authors of vlc would support all current versions of gnutls.

One option is to ask "does your media player really require TLS
support?" Maybe it's just a nice feature and you can do without it, so
add to package.use:

media-video/vlc -gnutls

It's something worth considering

>
> I put vlc ~x86 in package.keywords as instructed here,
> http://www.videolan.org/vlc/download-gentoo.html.
> box0=; cat /etc/portage/package.keywords
> media-video/vlc ~x86
>
> Turns out, it wasn't such a good idea after all.
>
> What would I have to do to downgrade vlc, gnutls and ffmpeg to the
> stable versions of the packages?
> I guess I'd have to remove their respective entries from
> /etc/portage/package.(accept)_keywords.
> box0=; cat /etc/portage/package.keywords
> media-video/vlc ~x86
> box0=; cat /etc/portage/package.accept_keywords
> =net-im/skype-4.2.0.11-r1 ~x86
> =sys-devel/gettext-0.18.3.1-r1 ~x86
> =net-libs/gnutls-3.2.5 ~x86
> =media-video/ffmpeg-1.2.4 ~x86
>
> How would I instruct emerge to do that properly?

Just run "emerge -avuND world" and emerge will do all the necessary
downgrades.

Then run "emerge -a --depclean" to remove any slotted libs that might
have been pulled in and are no longer needed (a simple emerge world does
not deal with those)

Or, you can try sidestep the issue and avoid gnutls completely as above.

Yet another option is to request that gnutls be slotted so that you can
have v2 and v3 at the same time and don't have to choose (openssl
already works this way). You do this by opening a feature request bug at
bugs.gentoo.org

-- 
Alan McKinnon
alan.mckinnon@×××××.com