python-version black list support

[alonbl]

Description:

Our CI broke today because of a new release of python-3.10.7 due to mypy bug[1]
Although it should not happen, it happened.
The immediate response would be to mask out (black list) python-3.10.7 until a new version of mypy is released.
However, there is no easy way to do so in matrix job without significant modification.

I thought of using the - operation but then the matrix is not effective, so I end up in duplicate the action invocation with conditionals.

I suggest something similar to the following to mask out a specific python release from installation, notice the python-version-blacklist new input parameter:

jobs:
  build:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version:
        - 3.7
        - 3.8
        - 3.9
        - 3.10
    steps:
    - uses: actions/checkout@v3
    - uses: actions/setup-python@v4
      with:
        python-version: ${{ matrix.python-version }}
        python-version-blacklist:                                   # <---- ADDITION
          - 3.10.7
    - run: python my_script.py

You may ask yourself why don't I put 3.10.7 in the matrix variable, it is because this variable is used not only for the this specific action but elsewhere in the workflow, and cannot be a full version. In our case the action/setup-python is executed within reusable composite action so it is not aware of the matrix at all. In our specific case adding this python-version-blacklist would have been done in a single place, and providing a fix for all our repositories.

[1] python/mypy#13627

Justification:

Allow to react fast to issues that exists in specific versions of python and support matrix.

Are you willing to submit a PR?

Yes, if it is acceptable.

[dmitry-shibanov]

Hello @alonbl. Thank you for your feature request. We'll investigate it.

[dmitry-shibanov]

Hello @alonbl. We're going to close the feature request because it won't simplify the usage of setup-python. It will require to maintain versions in python-version-blacklist for downloading. In this case it will be better to specify full version.