[gentoo-user] portage python USE flags.

[gentoo-user] portage python USE flags.

[Dale]

I have a quick question.  I sync'd a bit ago and noticed something a bit 
odd.  Here it is:

[ebuild     U *] sys-apps/portage-2.2.0_alpha34 [2.2.0_alpha33] 
USE="(ipc) -build -doc -epydoc -python2 -python3 (-selinux)" 
LINGUAS="-pl" 794 kB

I know portage needs python but check out the USE flags.  Both python2 
and python3 are disabled.  Shouldn't one of those be enabled?  Even 
better, shouldn't portage complain a bit about this before emerging?  
Thing is, I'm tempted to enable them both.  2.7 is currently being used 
but won't 3.1 be used eventually? Should I enable both or just emerge as 
is?

That is the unstable version so if this is a problem, I want to file a 
bug before someone else runs into this and ends up with a borked system.

Thanks.

Dale

:-)  :-)

Re: [gentoo-user] portage python USE flags.

[Indi]

On Thu, May 19, 2011 at 02:40:01AM +0200, Dale wrote:
> I have a quick question.  I sync'd a bit ago and noticed something a bit 
> odd.  Here it is:
> 
> [ebuild     U *] sys-apps/portage-2.2.0_alpha34 [2.2.0_alpha33] 
> USE="(ipc) -build -doc -epydoc -python2 -python3 (-selinux)" 
> LINGUAS="-pl" 794 kB
> 
> I know portage needs python but check out the USE flags.  Both python2 
> and python3 are disabled.  Shouldn't one of those be enabled?  Even 
> better, shouldn't portage complain a bit about this before emerging?  
> Thing is, I'm tempted to enable them both.  2.7 is currently being used 
> but won't 3.1 be used eventually? Should I enable both or just emerge as 
> is?
> 

Pretty sure that if you have -python2 or whatever that only works
against building things which have an optional python bit, and has no
effect on things you have which are python-based system bits.
The USE flags affect options, they don't bar things altogether.
I have "-gtk -qt4 -qt3support" in make.conf, but it doesn't stop me 
from installing gtk-based things -- just stops the building of
*optional* gtk guis.

Even so, I wouldn't do that with something as critical as python.

The real question is "why do you hate python"?
:)

-- 
caveat utilitor 
♫ ❤ ♫ ❤ ♫ ❤ ♫ 

Re: [gentoo-user] portage python USE flags.

[Alan McKinnon]

Apparently, though unproven, at 02:30 on Thursday 19 May 2011, Dale did opine 
thusly:

> I have a quick question.  I sync'd a bit ago and noticed something a bit
> odd.  Here it is:
> 
> [ebuild     U *] sys-apps/portage-2.2.0_alpha34 [2.2.0_alpha33]
> USE="(ipc) -build -doc -epydoc -python2 -python3 (-selinux)"
> LINGUAS="-pl" 794 kB
> 
> I know portage needs python but check out the USE flags.  Both python2
> and python3 are disabled.  Shouldn't one of those be enabled?  Even
> better, shouldn't portage complain a bit about this before emerging?
> Thing is, I'm tempted to enable them both.  2.7 is currently being used
> but won't 3.1 be used eventually? Should I enable both or just emerge as
> is?
> 
> That is the unstable version so if this is a problem, I want to file a
> bug before someone else runs into this and ends up with a borked system.

The solution, as always, is in the ebuild. But first a clarification:

USE flags are NOT some scheme where support will or will not be built, or that 
other packages will be magically removed somehow. They are programming 
variables and are used as such. Inside the ebuild, the code looks at the flag 
and does something with it. Usually it does what you expect:

python_dep="python3? ( =dev-lang/python-3* )
        !python2? ( !python3? (
                build? ( || ( dev-lang/python:2.7 dev-lang/python:2.6 ) )
                !build? ( || ( dev-lang/python:2.7 dev-lang/python:2.6 >=dev-
lang/python-3 ) )
        ) )
        python2? ( !python3? ( || ( dev-lang/python:2.7 dev-lang/python:2.6 ) 
) )"

What that basically comes down to (2nd and 3rd cases swapped for clarity) is:

python3 is set = require python-3
python2 is set and python3 is not set = require python-2.6 or python-2.7
python2 is not set python3 is not set = require python-2.6 or python-2.7

Elsewhere is the ebuild you get stuff like this:

        if use python3; then
                python_set_active_version 3
        elif use python2; then
                python_set_active_version 2

Which basically means "always set active version to python-2.x regardless of 
anything else unless USE=python-3, in which case set the active version to 
python-3.

So, no bug here, nothing to see, move along folks.


-- 
alan dot mckinnon at gmail dot com

Re: [gentoo-user] portage python USE flags.

[Peter Humphrey]

On Thursday 19 May 2011 01:30:32 Dale wrote:

> I know portage needs python but check out the USE flags.  Both python2
> and python3 are disabled.

If you check emerge --info you may find, as I do, that just python is 
enabled, without reference to the version. In that case I suggest you 
shouldn't tamper with it!

-- 
Rgds
Peter

Re: [gentoo-user] portage python USE flags.

[Dale]

Indi wrote:
> On Thu, May 19, 2011 at 02:40:01AM +0200, Dale wrote:
>    
>> I have a quick question.  I sync'd a bit ago and noticed something a bit
>> odd.  Here it is:
>>
>> [ebuild     U *] sys-apps/portage-2.2.0_alpha34 [2.2.0_alpha33]
>> USE="(ipc) -build -doc -epydoc -python2 -python3 (-selinux)"
>> LINGUAS="-pl" 794 kB
>>
>> I know portage needs python but check out the USE flags.  Both python2
>> and python3 are disabled.  Shouldn't one of those be enabled?  Even
>> better, shouldn't portage complain a bit about this before emerging?
>> Thing is, I'm tempted to enable them both.  2.7 is currently being used
>> but won't 3.1 be used eventually? Should I enable both or just emerge as
>> is?
>>
>>      
> Pretty sure that if you have -python2 or whatever that only works
> against building things which have an optional python bit, and has no
> effect on things you have which are python-based system bits.
> The USE flags affect options, they don't bar things altogether.
> I have "-gtk -qt4 -qt3support" in make.conf, but it doesn't stop me
> from installing gtk-based things -- just stops the building of
> *optional* gtk guis.
>
> Even so, I wouldn't do that with something as critical as python.
>
> The real question is "why do you hate python"?
> :)
>
>    

I don't hate python.  I didn't disable python either.  This just sort of 
popped up.  I check USE flags and I don't recall seeing this before.  
Then again, I don't question portage updates to much either.

I read other replies and it seems the ebuild is going to make sure 
everything stays sane so off to finish my updates.

Thanks to all.

Dale

:-)  :-)

Re: [gentoo-user] portage python USE flags.

[Adam Carter]

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I don't hate python.  I didn't disable python either.  This just sort of
popped up.  I check USE flags and I don't recall seeing this before.  Then
again, I don't question portage updates to much either.

>
> I read other replies and it seems the ebuild is going to make sure
> everything stays sane so off to finish my updates.
>

To get -pythonX, that would need to be set via IUSE in the build, or USE in
your make.conf right?

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