Re: [gentoo-python] Python 3 in Gentoo

[Thomas Sachau <tommy@gentoo.org>]

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Mike Gilbert schrieb:
> On Mon, Jul 30, 2012 at 3:36 AM, Dirkjan Ochtman <djc@gentoo.org> wrote:
>> I agree that installing both is probably overkill for most users. I
>> think the solution is somewhere outside the dev-lang/python package,
>> though, in having the system set or portage or whatever the hell it is
>> that first pulls in python prefer python-2.
> 
> I looked into this, and there are currently two things that will pull
> python-3 into a stage3:
> 
> 1. sys-apps/portage due to its >=dev-lang/python-2.7[ssl] dependency.
> 2. app-admin/python-updater has a bare "dev-lang/python" dependency.
> 
> I have verified that if you install python:2.7, and adjust those
> dependencies to the following, portage will no longer try to pull in
> python-3.2 on a world update.
> 
> sys-apps/portage:
> 
> DEPEND="|| ( =dev-lang/python-3*[ssl] dev-lang/python:2.7[ssl]
> dev-lang/python:2.6[threads,ssl] )"
> 
> app-admin/python-updater:
> 
> DEPEND="|| ( dev-lang/python-3* dev-lang/python-2* )"
> 
> The || deps are key here; this causes portage to weight an already
> installed package over the rest.
> 
> In fact, if you reverse the order of python-3 and python-2, that
> SHOULD cause python-2 to be pulled into the stage building process
> instead of python-3.
> 
> So, another possible alternative here is to scour the tree, replacing
> any dependencies on dev-lang/python with || deps. I believe
> python.eclass would also need to be updated. Does that sound like an
> acceptable solution?
> 
> 

If this prevents python-3 to be pulled in also python-2 does still
satisfies all requirements (for stage3 and for updates), then this looks
like an acceptable solution with less work. It would also mean, that
PYTHON_TARGETS could again just go with python2_7.

The only drawback i see with this solution is, that python dependencies
need to be done carefully, so that noone does accidently pull python-3
in again at some later point.

-- 

Thomas Sachau
Gentoo Linux Developer


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