Use cPython 3.5–compatible function definitions #3320
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Summary: In Python as of PEP 3102, function definitions may include keyword-only arguments after a splat (`def foo(x, *, y)`). But cPython 3.5 has a parser bug (<https://bugs.python.org/issue9232>) when trailing commas are used with this syntax, as in `def foo(x, *, y,)`. This is fixed in Python 3.6 and up, but not backported to 3.5, so for now we should make sure to omit these trailing commas. The change to `pyproject.toml` prevents Black from re-introducing these trailing commas. We leave `py27` in the `pyproject.toml` to avoid a mass reformat removing `u`-prefixes from Unicode string literals (which is fine, but should be a separate change for `.git-blame-ignore-revs`). We don’t run our full test suite on Python 3.5 yet, due to unrelated issues (primarily, lack of `assert_not_called` and that `json.loads` does not accept `bytes`). For now, it suffices to run `flake8` on both Python 3.5 and Python 3.7, because that at least parses all the code. Test Plan: That CI passes suffices. wchargin-branch: py35-fundefs
nfelt
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Mar 3, 2020
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Thanks for the fix! Running just flake8 on py3.5 seems like a good compromise to me :)
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nit: maybe call this lint-python-flake8 just to be clear to the uninitiated that it's also linting python? Since otherwise separating it out from lint-python is a little confusing.
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Sure; fine with me. Done.
wchargin-branch: py35-fundefs wchargin-source: 95560cf6984706951dbc83732c1c2b83dd871c3d
This was referenced Mar 3, 2020
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Summary:
In Python as of PEP 3102, function definitions may include keyword-only
arguments after a splat (
def foo(x, *, y)). But cPython 3.5 has aparser bug (https://bugs.python.org/issue9232) when trailing commas
are used with this syntax, as in
def foo(x, *, y,). This is fixed inPython 3.6 and up, but not backported to 3.5, so for now we should make
sure to omit these trailing commas.
The change to
pyproject.tomlprevents Black from re-introducing thesetrailing commas. We leave
py27in thepyproject.tomlto avoid a massreformat removing
u-prefixes from Unicode string literals (which isfine, but should be a separate change for Bazel
srcs_version).We don’t run our full test suite on Python 3.5 yet, due to unrelated
issues (primarily, lack of
assert_not_calledand thatjson.loadsdoes not accept
bytes). For now, it suffices to runflake8on bothPython 3.5 and Python 3.7, because that at least parses all the code.
Test Plan:
That CI passes suffices.
wchargin-branch: py35-fundefs