[gentoo-user] Migrating to python3_6 ?

[gentoo-user] Migrating to python3_6 ?

[james]

So,

I have been reading all sorts of things from you cannot get rid of 
python 2.7 to it's straightforward to leave python2_7.

"Jan 1 2020 python 2.7 is bye_bye"

If this is true, I'm not sure which to upgrade to  Python 3.6,7,8,9;
versus 3.7 seems most poputlar ?

I have these versions of python installed 2.7.15, 3.5.5 and 3.6.5
and these settings in make.conf::

  PYTHON_TARGETS=" python2_7 python3_6"
  PYTHON_SINGLE_TARGET="python3_6"

Sometimes it's hard to sort out the most accurate/current docs to read
from the older docs, related to various issues. I'm a none systemd 
gentoo user, and not the sharpest tac in the box.......(python_challenged?)

eix --installed-with-use python_targets_python2_7
When I run this command string, I get 157 ::


Here are a few of the docs that seem reasonable, but may not be the best 
guides to follow, on the journey from Python2 to Python3?


https://www.gentoo.org/support/news-items/2018-05-22-python3-6.html

https://stxnext.com/blog/2019/04/16/python-3-migration-guide/

https://packages.gentoo.org/useflags/python_single_target_python3_6

https://devguide.python.org/#status-of-python-branches

Perhaps I've missed a straightforward guide, or a way to mitigate when a 
package still want python2_7 ?


Info and guidance is most welcome.


James

[gentoo-user] Re: Migrating to python3_6 ?

[Grant Edwards]

On 2019-09-04, james <garftd@verizon.net> wrote:

> I have been reading all sorts of things from you cannot get rid of 
> python 2.7 to it's straightforward to leave python2_7.

In my experience, if you do a lot of stuff with raw byte streams
(e.g. implementing network protocols), switching from 2.7 to 3.x can
be rather painful.

For most other sorts of apps, it's fairly easy to write code that
works on both, and even easier to just switch over.

-- 
Grant Edwards               grant.b.edwards        Yow! Used staples are good
                                  at               with SOY SAUCE!
                              gmail.com            

[gentoo-user] Re: Migrating to python3_6 ?

[Nikos Chantziaras]

On 04/09/2019 07:42, james wrote:
> I have these versions of python installed 2.7.15, 3.5.5 and 3.6.5
> and these settings in make.conf::
> 
>   PYTHON_TARGETS=" python2_7 python3_6"
>   PYTHON_SINGLE_TARGET="python3_6"
> 
> Sometimes it's hard to sort out the most accurate/current docs to read
> from the older docs, related to various issues.
I don't set any of these. I let portage use its recommended defaults. Do 
you have a reason to use something else?

Re: [gentoo-user] Re: Migrating to python3_6 ?

[James Stevenson]

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Has anyone tried adding 3.7 to the python targets yet? I got some strange
errors when I tried last week.

James

On Thu, 5 Sep 2019, 16:13 Nikos Chantziaras, <realnc@gmail.com> wrote:

> On 04/09/2019 07:42, james wrote:
> > I have these versions of python installed 2.7.15, 3.5.5 and 3.6.5
> > and these settings in make.conf::
> >
> >   PYTHON_TARGETS=" python2_7 python3_6"
> >   PYTHON_SINGLE_TARGET="python3_6"
> >
> > Sometimes it's hard to sort out the most accurate/current docs to read
> > from the older docs, related to various issues.
> I don't set any of these. I let portage use its recommended defaults. Do
> you have a reason to use something else?
>
>
>

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Re: [gentoo-user] Re: Migrating to python3_6 ?

[james]

On 9/5/19 11:12 AM, Nikos Chantziaras wrote:
> On 04/09/2019 07:42, james wrote:
>> I have these versions of python installed 2.7.15, 3.5.5 and 3.6.5
>> and these settings in make.conf::
>>
>> ??PYTHON_TARGETS=" python2_7 python3_6"
>> ??PYTHON_SINGLE_TARGET="python3_6"
>>
>> Sometimes it's hard to sort out the most accurate/current docs to read
>> from the older docs, related to various issues.
> I don't set any of these. I let portage use its recommended defaults. Do 
> you have a reason to use something else?

It's the way most docs suggest::


https://wiki.gentoo.org/wiki/Python


Although the file was touched recently::
This page was last edited on 3 August 2019, at 00:26.

It does not seem to be agressive on the versions of Python. I try to use
the latest 'stable' versions, as set in the make.conf file. Feel 
encourage to enlighten me on a better pathway, particulary on the 
pending (1/1/20) end to python 2.7.


James

Re: [gentoo-user] Re: Migrating to python3_6 ?

[Mick]

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On Thursday, 5 September 2019 21:38:16 BST james wrote:
> On 9/5/19 11:12 AM, Nikos Chantziaras wrote:
> > On 04/09/2019 07:42, james wrote:
> >> I have these versions of python installed 2.7.15, 3.5.5 and 3.6.5
> >> and these settings in make.conf::
> >> 
> >> ??PYTHON_TARGETS=" python2_7 python3_6"
> >> ??PYTHON_SINGLE_TARGET="python3_6"
> >> 
> >> Sometimes it's hard to sort out the most accurate/current docs to read
> >> from the older docs, related to various issues.
> > 
> > I don't set any of these. I let portage use its recommended defaults. Do
> > you have a reason to use something else?
> 
> It's the way most docs suggest::
> 
> 
> https://wiki.gentoo.org/wiki/Python

As I understand this wiki page, you only need to specify a particular python 
version if you require a specific slot installed, which happens to be 
different from the default python slots managed by normal portage usage and 
reverse dependencies of individual packages.


> Although the file was touched recently::
> This page was last edited on 3 August 2019, at 00:26.
> 
> It does not seem to be agressive on the versions of Python. I try to use
> the latest 'stable' versions, as set in the make.conf file. Feel
> encourage to enlighten me on a better pathway, particulary on the
> pending (1/1/20) end to python 2.7.
> 
> 
> James

In order to use the latest stable python versions, I would remove any manually 
specified python targets from make.conf, then 'emerge @preserved-rebuild', 
then 'emerge --depclean -v -p' and for good measure 'revdep-rebuild'.  When 
python 2.7 becomes deprecated in the future it will fall out of the portage 
tree and your regular emerge will unmerge it.

-- 
Regards,

Mick

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