Add Python version to output of black --version

[CharlesB2]

Describe the bug

With structural pattern matching, Black fails with an invalid syntax, even though target version is py310.

To Reproduce

For example, take this code:

from rest_framework import serializers
from audit.models.health_check import ParentModel

class ServiceRelatedField(serializers.Serializer):
    def to_representation(self, value):
        match value:
            case ParentModel():
                data = {"name": value.actor.login}
            case _:
                raise Exception("Unexpected type of service object")
        data["id"] = value.id
        data["class"] = self.context["class"]
        return data

And run it with these arguments:

$ black  --target-version py310 file.py

The resulting error is:

error: cannot format file.py: cannot use --safe with this file; failed to parse source file AST: invalid syntax (, line 6)
This could be caused by running Black with an older Python version that does not support new syntax used in your source file.

Reproduced also with black show

Expected behavior

Environment

• Black's version: 2.33.0
• OS and Python version: MacOs 12.3/Python 3.10.2

[JelleZijlstra]

I can't reproduce this. Make sure you're running Black itself under Python 3.10+ too:

% python -m black --target-version=py310 matchsamplebug.py
All done! ✨ 🍰 ✨
1 file left unchanged.
% python -m black --version
python -m black, 22.3.0 (compiled: no)
% python --version 
Python 3.11.0a6+

[CharlesB2]

Thanks, that was the error indeed!

[CharlesB2]

BTW it would be helpful to know with which is the Python version in the output of black --version

[JelleZijlstra]

BTW it would be helpful to know with which is the Python version in the output of black --version

Good point, reopening this issue to reflect that suggestion

[CharlesB2]

Also it may be fair to issue an error or a warning if --target-version is py310 but isn't running with Python 3.10