1573182 - flake8 linter fails to parse PEP484 annotations in Python 3 files

Status: RESOLVED DUPLICATE of bug 1567642

(Developer Infrastructure :: Lint and Formatting, task)

Description

[Beth Rennie [:beth] (she/her) - OOO until Sept 14]

While adding a new Python 3 only file, I ran into the issue that our flake8 linter only supports python 2 files. Adding a python 3 file with PEP 484 type annotations, e.g.

def main(args: List[str]) -> int:
    pass

will result in the linter failing to parse the file with the error: SyntaxError: invalid syntax (E999)

Here is a try push with a failing flake8 job.

Comment 1

[Andrew Halberstadt [:ahal]]

This is a known issue. Until that's fixed, your only options are to not use type annotations or add your file to the flake8 exclude list:
https://searchfox.org/mozilla-central/source/.flake8#3

If you go the latter route, please add a new section of exclusions via a comment. Something like # These files have Python 3-only syntax (see bug 1567642).