asottile-archive / flake8-2020 Goto Github PK

Should it test version[0] and not sys.version[0]?

https://github.com/asottile/flake8-2020/blob/f60d4d6b35ec50d6554fc6035c6d9470f628f089/tests/flake8_2020_test.py#L109

With this code:

import six
if not six.PY3:
    pass

The plugin correctly gives:

$ flake8 --select YTT 1.py
1.py:2:8: YTT202: `six.PY3` referenced (python4), use `not six.PY2`

Perhaps it could detect the not before six.PY3, and suggest a clean six.PY2 instead?

For example:

$ flake8 --select YTT 1.py
1.py:2:X: YTT20X: `not six.PY3` referenced (python4), use `six.PY2`

That is:

# Bad
if not six.PY3:

# Better (sort of)
if not not six.PY2:

# Best
if six.PY2:

I have observed code using platform.python_version_tuple to check version numbers, but since it is a tuple of strings it gets tripped up by Python 3.10:

>>> platform.python_version_tuple()
('3', '10', '0a3')
>>> platform.python_version_tuple() > ("3", "3")
False
>>> "10" > "3"
False

>>> platform.python_version_tuple()
('3', '8', '5')
>>> platform.python_version_tuple() > ("3", "3")
True
>>> 
>>> "8" > "3"
True

Would you be interested in having a check for this?

I got this in a PR today:

python_version = float(sys.version_info.major) + 0.1 * float(
    sys.version_info.minor,
)

flake8-2020 doesn't catch this, would it be a welcome addition?

Originally from #4 (comment)

Right now it's reported as YTT103

I haven't seen this one in the wild, but I think it's ~reasonably well defined for 3.0 - 3.9 so it's possible:

Python 3.5.7 (default, Mar 30 2019, 01:05:18) 
[GCC 7.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.version >= '3.5'
True

Python 3.10.0a0 (default, Jul 18 2019, 06:46:14) 
[GCC 7.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.version >= '3.5'
False

the version slice should probably only check for :1 and :3 as there's a few "legitimate" usages of slicing sys.version I've seen in the wild, in particular here's one from cpython that seems to be well defined:

https://github.com/python/cpython/blob/da27d9b9dc44913ffee8f28d9638985eaaa03755/Lib/distutils/msvc9compiler.py#L174-L179

@hugovk submitted a pull request to urllib3 based on this plugin: urllib3/urllib3#1669. Thanks! But it failed to catch all issues, as PY3 was sometimes imported directly. See urllib3/urllib3#2004 for examples.

This may cause false positives, though.

This is used in three places in scipy, and I've seen this sort of thing in other repos too:

if sys.version_info.major >= 3 and sys.version_info.minor >= 5:
    from math import gcd
else:
    from fractions import gcd

The if is incorrectly False for 4.0 - 4.4, 5.0 - 5.4, etc.

To fix:

-if sys.version_info.major >= 3 and sys.version_info.minor >= 5:
+if sys.version_info >= (3, 5):
     from math import gcd
 else:
     from fractions import gcd

Can this easily be detected?

Not sure whether this can be properly fixed now, but at least I'm going post is as feedback item.

I do expect libraries to follow at least some kind of semver-alike versioning. If there are breaking changes, I do expect major version to be bumped. However it's not the case with flake8-2020, we got an error when trying to update 1.6.1 -> 1.7.0:

flake8-2020 1.7.0 depends on flake8>=5

We do use flake8 less than 5, because there are other plugins (namely, wemake-python-styleguide) which require older flake8. And changing to the newer flake8 is a major version bump. This was really unexpected when flake8-2020 got a major change breaking backward compatibility without bumping its major version.

Could you please check and maybe at least somehow improve the release process to avoid such issues in the future? Ideally would be to fix current releases, but I understand this is unlikely to happen....

Very similar to YTT101, but for platform.python_version:

Python 3.10.0a2+ (heads/master:bbeb2d2, Nov 13 2020, 10:34:11)
[GCC 7.5.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import platform
>>> platform.python_version()[:3]
'3.1'