Re: [gentoo-python] Python 3 in Gentoo

[Michał Górny]

On Sun, 2 Sep 2012 13:54:13 -0400
Mike Gilbert <floppym@g.o> wrote:

> On Sun, Sep 2, 2012 at 1:34 PM, Michał Górny <mgorny@g.o>
> wrote:
> > On Sun, 2 Sep 2012 13:16:38 -0400
> > Mike Gilbert <floppym@g.o> wrote:
> >
> >> On Sun, Sep 2, 2012 at 8:21 AM, Thomas Sachau <tommy@g.o>
> >> wrote:
> >> > Mike Gilbert schrieb:
> >> >> On Mon, Aug 13, 2012 at 3:38 PM, Dirkjan Ochtman
> >> >> <djc@g.o> wrote:
> >> >>> On Mon, Aug 13, 2012 at 9:07 PM, Richard Yao <ryao@g.o>
> >> >>> wrote:
> >> >>>>> Does this seem like a viable option? Is anyone going to
> >> >>>>> volunteer to take it from here?
> >> >>>>
> >> >>>> I can try to make time to make these changes this weekend if
> >> >>>> everyone is fine with that.
> >> >>>
> >> >>> I think we should inform gentoo-dev first.
> >> >>>
> >> >>
> >> >> Just in case someone is waiting for me to take some further
> >> >> actions on this, please don't wait on me. I really don't have
> >> >> the motivation to carry this plan any further.
> >> >>
> >> >> If someone else wants to carry the torch, I am happy to assist.
> >> >>
> >> >>
> >> >
> >> > Just to get the right summary:
> >> >
> >> > The plan is now to replace all dependencies in ebuilds, which
> >> > have either "dev-lang/python" or something like
> >> > ">=dev-lang/python-X.Y" to use "virtual/python" instead?
> >> >
> >>
> >> That's right.
> >>
> >> > What about versioned dependencies exluding python versions still
> >> > in the main tree like ">=dev-lang/python-2.7"?
> >> >
> >>
> >> In this case the virtual would not work. Instead, it could be
> >> replaced with this:
> >>
> >> || ( =dev-lang/python-2.7* =dev-lang/python-3* )
> >>
> >> Similarly, >=dev-lang/python-2.6 could be replaced with this:
> >>
> >> || ( =dev-lang/python-2.7* =dev-lang/python-2.6*
> >> =dev-lang/python-3* )
> >
> > You could go with virtual/python-2.7, -2.6, -2.5 being an
> > appropriate minimal version.
> >
>
> I gave that idea some thought, but I think it would be a somewhat
> confusing (it makes my head hurt).
>
> There are actually a few ways I could see a versioned virtual being
> implemented; can you articulate exactly what each virtual version
> would have in RDEPEND and how it would be used in other ebuilds?

Well, one not-so-crazy idea is that we have:

  virtual -2.5, SLOT="2.5+": || ( =python-2* =python-3* )
  virtual -2.6, SLOT="2.6+": || ( python:2.7 python:2.6 =python-3* )
  virtual -2.7, SLOT="2.7+": || ( python:2.7 =python-3* )

  # optioanlly, I think it may be nicer than =python-3* in ebuilds
  virtual -3.1, SLOT="3.1+": =python-3*

It's a bit hacky but with it, you can then do:

  RDEPEND="virtual/python:2.6+"

which is quite self-explanatory.

Alternatively, we could use some recurrency :D.

  virtual -3.1, SLOT="3.1+": =python-3*
  virtual -2.7, SLOT="2.7+": || ( python:2.7 virtual/python:3.1+ )
  virtual -2.6, SLOT="2.6+": || ( virtual/python:2.7+ python:2.6 )
  virtual -2.5, SLOT="2.5+": || ( virtual/python:2.6+ python:2.5 )

-- 
Best regards,
Michał Górny