Re: [gentoo-user] Blocking object does not exist...

[Alan McKinnon]

On Thursday 01 January 2009 10:10:08 meino.cramer@×××.de wrote:
> Hi,
>
> HAPPY NEW YEAR !  :O)
>
>
> I have got a problem while updateing my Gentoo-Linux-box:
>
> Witzh this command:
> emerge Net-Daemon PlRPC DBI rxvt-unicode gstreamer e2fsprogs-libs nano
> e2fsprogs zynaddsubfx sox boost autounmask cmake smplayer kdelibs wxGTK
> firehol xulrunner xorg-server vlc
>
>
> I got (beside a list of updateable/new package) the following warning:
>
> [blocks B     ] x11-libs/qt-core ("x11-libs/qt-core" is blocking
> x11-libs/qt-4.3.3)
> > [blocks B     ] <=x11-libs/qt-4.4.0_alpha:4
> ("<=x11-libs/qt-4.4.0_alpha:4" is blocking x11-libs/qt-script-4.4.2,
> x11-libs/qt-dbus-4.4.2, x11-libs/qt-qt3support-4.4.2,
> x11-libs/qt-sql-4.4.2, x11-libs/qt-gui-4.4.2, x11-libs/qt-svg-4.4.2,
> x11-libs/qt-test-4.4.2, x11-libs/qt-core-4.4.2, x11-libs/qt-opengl-4.4.2)
>
> Due to that I decided to do a
>
> emerge -C qt-core
>
> which was answered with:
>
> --- Couldn't find 'qt-core' to unmerge.
>
>
> How cabn I solve the problem to get blocking packages, which do  not
> exist?

Long long ago when I used to fix electronic bits, the best advice I ever ound 
for my techies was

"OYFEAL": Open your fscking eyes and look. Some of that would help you a lot 
right now :-)

When emerge runs, it builds a tree in memory of what it intends to do, that's 
where the blockers come from. So it doesn't have to be what you already have, 
it's portage telling you it can't follow your instructions.

Look carefully at the first block. It clearly says that qt-core (no version) 
cannot be merged because of a block with qt-4.3.3. The second block says that 
all versions of qt less than or equal to 4.4.0_alpha block a bunch of 4.4.2 
qt stuff.

What happened here is that qt was split into several small package instead of 
one huge one. The new is therefore not compatible with the old and cannot 
co-exist, so you must unmerge the old version to be able to put the new ones 
on the system. You want:

unmerge -avC qt
emerge -av qt

IIRC, there is a new qt meta package that will install core and others in step 
2. If not, just emerge qt-core manually.

emerge's block output is worded confusingly, the exact selection of words can 
lead you to believe that you have to do B in order to do A, when actually 
it's the other way round. this is because the devs block B in A's ebuild and 
also block A in B's ebuild, so that no stupid circumstances can arise. Best 
way to wrap your head around it is to open each ebuild, read it and compare 
it to the console output. Sooner or later a lightbulb will go on in your 
head, at least that's how it worked for me and most others I've helped over 
the years.



-- 
alan dot mckinnon at gmail dot com