Re: [PATCH 0/8] Initial support for Python 3

[Pete Wyckoff <pw@padd.com>]

john@keeping.me.uk wrote on Sun, 13 Jan 2013 00:41 +0000:
> On Sat, Jan 12, 2013 at 06:43:04PM -0500, Pete Wyckoff wrote:
> > Can you give me some hints about the byte/unicode string issues
> > in git-p4.py?  There's really only one place that does:
> > 
> >     p4 = subprocess.Popen("p4 -G ...")
> >     marshal.load(p4.stdout)
> > 
> > If that's the only issue, this might not be too paniful.
> 
> The problem is that what gets loaded there is a dictionary (encoded by
> p4) that maps byte strings to byte strings, so all of the accesses to
> that dictionary need to either:
> 
>    1) explicitly call encode() on a string constant
> or 2) use a byte string constant with a "b" prefix
> 
> Or we could re-write the dictionary once, which handles the keys... but
> some of the values are also used as strings and we can't handle that as
> a one-off conversion since in other places we really do want the byte
> string (think content of binary files).
> 
> Basically a thorough audit of all access to variables that come from p4
> would be needed, with explicit decode()s for authors, dates, etc.

Your auto-conversion snippet in the follow-up mail would work
fine for most keys and values.  A few perforce docs and some
playing around convince me that it is mostly utf-8, except for
file data for particular types.

I'd still rather handle each command separately, and think about
the conversions, to do it right in the long run.

> > I hesitated to take Sebastian's changes due to the huge number of
> > print() lines, but maybe a 2to3 approach would make that aspect
> > of python3 support not too onerous.
> 
> I think we'd want to change to print() eventually and having a single
> codebase for 2 and 3 would be nicer for development, but I think we need
> to be able to say "no one is using Python 2.5 or earlier" before we can
> do that and I'm not sure we're there yet.  From where we are at the
> moment I think 2to3 is a good answer, particularly where we're already
> using distutils to generate a release image.

Agreed.  The 2to3 diff is large but straightforward.  But these
p4 -G interface errors require a lot of thought and work.  I'm
not too eager to work on this yet.

Thanks.

		-- Pete