Subject: Re: [PATCH] doc: mention Python 3.x supports

From: Đoàn Trần Công Danh <[email-masked]>
Date: Wed, 16 Dec 2020 00:38:45 +0700

On 2020-12-14 15:00:00-0800, Junio C Hamano <[email-masked]> wrote:

Sorry, I didn't receive this email, I found your reply when looking
into public-inbox's archive. (I guess it's because of Google global
outage).

> Đoàn Trần Công Danh  <[email-masked]> writes:
> 
> > Commit 0b4396f068, (git-p4: make python2.7 the oldest supported version,
> > 2019-12-13) pointed out that git-p4 uses Python 2.7-or-later features
> > in the code.
> >
> > In addition, git-p4 gained enough support for Python 3 from
> > 6cec21a82f, (git-p4: encode/decode communication with p4 for
> > python3, 2019-12-13).
> 
> I am not a Perforce user, so with that in mind, please help me make
> sure I understand the situation well.  The statement "not 3.x, which
> is not supported by Perforce" is from early 2013, and 6cec21a82f
> talks about the format of marshalled dict object that comes out of
> p4 (Perforce) tool that needs to be read in a certain way to be
> compatible with Python3.  Does that mean sometime in these 6 years,
> Perforce started supporting 3.x?

AFAIK, p4 is an executable binary (in the sense of ELF binaries) from
forever. And its {in,out}put is in arbitrary encoding, while Python 3
expects UCS-2 or UCS-4 encoding. 6cec21a82f adds code to decode to
Python 3 string to overcome this limitation.

Not related, but Perforce's official Python bindings supports Python 3
from at least 2013 [p4r13]. And they still maintain in [PyPI].
That binding requires compiling with Python Development files, though.

Anyway, I added Yang Zhao to Cc to clarify.

@Yang: Would you please verify what I've said?

> The change to INSTALL just drops the mention of 3.x; do we want to
> specifically say that any version of 3.x is OK, or is it generally
> accepted that Python 3.x is "later" than "Python 2.7"?

I think it's generally accepted since there're no Python 2.x version
that is "later" than Python 2.7.
I haven't check the whole git-p4 but in general, a lot of Python script
said support 2.7 AND 3.y with y is a specific number,
since some scripts can work with 2.7 and e.g. 3.4+ but not 3.3.
I can add them into "INSTALL" if it looks better.

p4r13: https://www.perforce.com/perforce/r13.1/manuals/p4script/03_python.html
PyPI: https://pypi.org/project/p4python/

-- 
Danh