Re: [gentoo-user] How to get rid of Python2 (where possible)

[Tom Wijsman]

On Fri, 28 Mar 2014 11:42:59 +0100
Helmut Jarausch <jarausch@××××××××××××××××.de> wrote:

> sys-apps/portage:0
>
>    (sys-apps/portage-9999:0/0::gentoo, ebuild scheduled for merge)
> pulled in by
>      sys-apps/portage (Argument)
>
>    (sys-apps/portage-9999:0/0::gentoo, installed) pulled in by
>
> sys-apps/portage[**SNIP**] required by
> (app-portage/gentoolkit-dev-0.2.8.3-r1:0/0::gentoo, installed)
>
> sys-apps/portage[**SNIP**] required by
> (app-admin/webapp-config-1.53:0/0::gentoo, installed)
>
> sys-apps/portage[**SNIP**] required by
> (app-portage/flaggie-0.2.1:0/0::gentoo, installed)

The thing with Python is that it wants 'packages that support Python'
depend on 'Python packages that have the same versions supported'.

Iotw, from the above example; let's say the reverse dependencies
gentoolkit-dev, webapp-config, flaggie, ... were build with 2.x and
with 3.x, they would want both 2.x and 3.x set on sys-apps/portage.

If you drop 2.x you can't just rebuild Portage, you'll need to rebuild
the reverse deps as well; such that they no longer want 2.x on Portage.

So, when changing PYTHON_TARGET in make.conf; you will want to do
something along the lines of `emerge -auvDN @world --backtrack=9001`,
this to ensure that the reverse dependencies of Portage no longer
depend on Portage having the previously set Python versions.

Portage will then go ahead and rebuild both Portage and its reverse
dependencies; that way, it doesn't create the conflict you saw.

(Backtracking 9001 so it is sufficiently high to not cause conflicts)

-- 
With kind regards,

Tom Wijsman (TomWij)
Gentoo Developer

E-mail address  : TomWij@g.o
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