stops the monkeypatch on lib2to3 grammar

[moore3071]

Lib2to3 provides a proper grammar without exec statements for Python 3 come Python 3.7.5.
Since Python 3.7.5 was just released, it might be wise to delay this pull request for a brief amount of time so those using system-based package managers can catch up.

[bwendling]

Unfortunately this doesn't work for Python 2, so it'll fail if someone tries to use Python 2...

[hartwork]

@bwendling since Python 2 support is out the door by now, does this change the evaluation of this pull request for 2023?

[bwendling]

@hartwork We could probably be more brutal with removing Python 2 from YAPF. For instance, we probably don't need the PY3 variable anymore either. This also needs to go into the CHANGELOG and README files.

[hartwork]

@bwendling good point 👍

Regarding change log and readme, I wonder if changelog should be all at once when making a release or distributed in pull request but with the constant potential for merge conflicts — both have downsides. What do you think?

One thing I should definitionally mention: use of python_grammar_no_print_and_exec_statement seems to require Python >=3.8. How do you feel about dropping support for Python 3.7? For proof:

# python3.7 -c 'from lib2to3 import pygram; print("\n".join(dir(pygram)))' | grep python_grammar
python_grammar
python_grammar_no_print_statement

# python3.7 --version
Python 3.7.16

If https://www.python.org/downloads/ is correct, 3.7 goes end-of-life 2023-06-27 i.e. in two months.

I'm also wondering if @moore3071 is still interested in this pull request, since their profile shows no GitHub activity after 2019.
@moore3071 are you still interested in the pull request?

[bwendling]

I'm not yet comfortably removing 3.7 support as there's likely to be 3.7 code still in use in a lot of places (e.g. Google).

As for updating the CHANGELOG, I know it's a hassle, but I feel that if we stop updating it with each commit then it'll be that much harder to gather the documentation for a release.

[hartwork]

I'm not yet comfortably removing 3.7 support as there's likely to be 3.7 code still in use in a lot of places (e.g. Google).

@bwendling alright, it's not dead yet. Now's a great time to start wearing a "Python 3.7 is almost dead!" shirt at work 😃

As for updating the CHANGELOG, I know it's a hassle, but I feel that if we stop updating it with each commit then it'll be that much harder to gather the documentation for a release.

Alright! 👍

[hartwork]

@bwendling can we close this as superseded by #1090?