W605 error while checking docstrings with regex inside it (again) v.2.5.0

[AlexArcPy]

This is the same issue as #822 and #795, it is giving the same error.

import re
def test_regex_function():
    """
    Return compiled regex of which allows to process only specific file
    paths or extensions, e.g. r"^.*\.svg$".
    :return:
    """
    return re.compile(r"^.*\.svg$")

Error:

W605 invalid escape sequence '\.'

Version:

$ pycodestyle --version
2.5.0

It was supposed to be fixed by #818 and merged to the master. However, the error persists. Any workarounds?

[asottile]

The lint is correct here, that docstring will become a syntax error in 3.8

You want to prefix your docstring with an r to make it a raw string or escape your backslash

The linked PR only corrects the position of the error message

If you'd like a tool which will autofix this, one of the automatic rewrites of pyupgrade covers this

[AlexArcPy]

@asottile ah thanks for the clarification. So, in 3.8 this docstring would also give a syntax error?

def foo():
  """add C:\Program Files\Git\bin on Windows to the PATH"""
  pass

Currently giving

W605 invalid escape sequence '\P'
W605 invalid escape sequence '\G'

[asottile]

yes, that one will as well

in fact today it produces what you probably wouldn't expect due to \b:

>>> foo.__doc__
'add C:\\Program Files\\Git\x08in on Windows to the PATH'
>>> print(foo.__doc__)
add C:\Program Files\Giin on Windows to the PATH

If you want to see the py38 behaviour and have access to py36 / py37 you can use:

$ python3.7 -Werror -c '"""foo\qar"""'
  File "<string>", line 1
SyntaxError: invalid escape sequence \q

[AlexArcPy]

Ah brilliant, thanks a ton for clarifying!