Forbid to use \r in line breaks

[sobolevn]

Rule request

Thesis

Forbid to use \r in your line breaks.

Related:
https://github.com/openstack/hacking/blob/master/hacking/checks/other.py#L23-L34

Reasoning

It is hard to catch and requires special tools for it.

[sobolevn]

My research

Testing before writing code:

import io
import tokenize
from textwrap import dedent

def factory(code: str):
    lines = io.StringIO(dedent(code))
    return list(tokenize.generate_tokens(lambda: next(lines)))

And using it:

>>> factory('1 + 2\r\n')
[TokenInfo(type=2 (NUMBER), string='1', start=(1, 0), end=(1, 1), line='1 + 2\r\n'), TokenInfo(type=54 (OP), string='+', start=(1, 2), end=(1, 3), line='1 + 2\r\n'), TokenInfo(type=2 (NUMBER), string='2', start=(1, 4), end=(1, 5), line='1 + 2\r\n'), TokenInfo(type=4 (NEWLINE), string='\r\n', start=(1, 5), end=(1, 7), line='1 + 2\r\n'), TokenInfo(type=0 (ENDMARKER), string='', start=(2, 0), end=(2, 0), line='')]

Here we go! We can create visit_newline somewhere in https://github.com/wemake-services/wemake-python-styleguide/blob/master/wemake_python_styleguide/visitors/tokenize/syntax.py

And test it in https://github.com/wemake-services/wemake-python-styleguide/tree/master/tests/test_visitors/test_tokenize