[Python-Dev] (Looking for) A Retrospective on the Move to Python 3

[Victor Stinner]

I gave the talk "Python 3: 10 years later" at FOSDEM and Pycon Italy
and will give it again at Pycon US next month:
https://fosdem.org/2018/schedule/event/python3/

My talk is focused on the migration path. How to "port" Python 2 code
to Python 3, 2to3 tool, six module, things done to make the migration
simpler, etc.

Victor

2018-04-26 18:25 GMT+02:00 Eric Snow <ericsnowcurrently at gmail.com>:
> In pondering our approach to future Python major releases, I found
> myself considering the experience we've had with Python 3.  The whole
> Py3k effort predates my involvement in the community so I missed a
> bunch of context about the motivations, decisions, and challenges.
> While I've pieced some of that together over the years now since I've
> been around, I've certainly seen much of the aftermath.  For me, at
> least, it would be helpful to have a bit more insight into the
> history. :)
>
> With that in mind, it would be worth having an informational PEP with
> an authoritative retrospective on the lessons learned from the Python
> 3 effort (and transition).  Consider it a sort of autobiography,
> "memoirs on the python-dev change to Python 3". :)  At this point the
> transition has settled in enough that we should be able to present a
> relatively objective (and consistent) view, while we're not so far
> removed that we've forgotten anything important. :)  If such a
> document already exists then I'd love a pointer to it.
>
> The document would benefit (among others):
>
> * python-dev (by giving us a clear viewpoint to inform decisions about
> future releases)
> * new-comers to Python that want more insight into the language
> * folks transitioning from 2 to 3
> * communities that have (or think they have) problems similar to those
> we faced in Python 2
>
> The PEP doesn't even have to be done all at once, nor by one person.
> In fact, there are many viewpoints that would add value to the
> document.  Hence it would probably make sense to encourage broad
> participation and then have a single editor to effect a single voice
> in the document.
>
> The contents of the retrospective document should probably cover a
> broad range of topics, since there's so much to learn from the move to
> Python 3.  To give an indication of what I mean, I've included a rough
> outline at the bottom of this message.
>
> So...I typically strongly avoid making proposals that I'm not willing
> to execute.  However, in this case I simply do not have enough
> experience in the history to feel comfortable doing a good job of it
> in a reasonable amount of time (which matters due to the tendency of
> valuable info to fade away). :/  I have no expectation that someone
> will pick this up, though I do hope since the benefit would be
> significant.  My apologies in advance if this wasted anyone's time.
>
> -eric
>
>
> ++++++++++++++++++++++++++++++++
>
> I'd hope to see something along the lines of (at least) the following,
> in rough order:
>
> * a concise summary of the document at the top (very meta, I know :) )
>   + what were we solving?
>   + what was the solution?
>   + why do it that way?
>   + what went right?
>   + what went wrong?
>   + impact on the community
>   + impact on core dev contribution
> * timeline
> * key players (and level of involvement)
>   + old guard core devs
>   + new guard
>   + folks brought on for Py3k (e.g. IIRC a swarm of Googlers dove in)
>   + non-core-devs
> * motivations
> * expectations (e.g. time frames, community reaction)
> * corresponding results
> * a summary of what we did
> * alternative approaches
> * what went right (and was it on purpose :) )
> * what went wrong (e.g. io) and why
> * how the Py3k project differed from normal python-dev workflow (e.g.
> pace, decision-making, communications)
> * lasting impact of python-dev
> * key things that would have been better if done differently
> * key decisions/planning (mostly a priori to the release work)
>   + scope of backward compatibility
>   + process (using PEPs with PEPs 30xx guiding)
>   + schedule
>   + specific changes (i.e. PEPs 31xx)
>   + what was left out (and why)
>   + plans to help library and app authors transition (e.g. 2to3)
>   + feature/schedule overlap with Python 2 (i.e. 2.6 and 2.7)
>   + the language moratorium
> * things that got missed and why
>   + unicode/bytes in some stdlib modules (and builtins?)
> * things that were overdone (and how that got missed)
>   + unicode/bytes in some stdlib modules (and builtins?)
> * (last but not least) challenges faced by folks working to transition
> their exiting code to Python 3
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