Enable Black - Python Auto Formmatter

[kaxil]

Enable Black (https://github.com/psf/black) using pre-commit

---

Make sure to mark the boxes below before creating PR: [x]

• Description above provides context of the change
• Unit tests coverage for changes (not needed for documentation changes)
• Target Github ISSUE in description if exists
• Commits follow "How to write a good git commit message"
• Relevant documentation is updated including usage instructions.
• I will engage committers as explained in Contribution Workflow Example.

---

In case of fundamental code change, Airflow Improvement Proposal (AIP) is needed.
In case of a new dependency, check compliance with the ASF 3rd Party License Policy.
In case of backwards incompatible changes please leave a note in UPDATING.md.
Read the Pull Request Guidelines for more information.

[kaxil]

Do you guys have any opinion if we should delay "Black" or do it now?

We can also enable this on v1-10-test. so shouldn't make backporting difficult.

[mik-laj]

Have you considered enabling the "--skip-string-normalization" option? This should reduce the number of changes without compromising the readability of the code.

  -S, --skip-string-normalization
                                  Don't normalize string quotes or prefixes.

Thanks to this, we will only have whitespace changes.

[kaxil]

Have you considered enabling the "--skip-string-normalization" option? This should reduce the number of changes without compromising the readability of the code.

  -S, --skip-string-normalization
                                  Don't normalize string quotes or prefixes.

Thanks to this, we will only have whitespace changes.

Applied

[github-actions]

The Build Workflow run is cancelling this PR. It has some failed jobs matching ^Pylint$,^Static checks$,^Build docs$,^Spell check docs$,^Backport packages$,^Checks: Helm tests$,^Test OpenAPI*.

[github-actions]

The Workflow run is cancelling this PR. It has some failed jobs matching ^Pylint$,^Static checks,^Build docs$,^Spell check docs$,^Backport packages$,^Provider packages,^Checks: Helm tests$,^Test OpenAPI*.

[kaxil]

The first commit contains the configuration only: 29e19fa

The 2nd commit actually applies black: 9bdaf18f7

[turbaszek]

Any reason for this exclude?

[kaxil]

Yes, black had issues with it i.e. it couldn't reproduce the same file pre and post black so it would be good to ignore them for now

❯ pre-commit run black -a
black....................................................................Failed
- hook id: black
- exit code: 123

error: cannot format /Users/kaxilnaik/Documents/Github/astronomer/airflow/airflow/configuration.py: INTERNAL ERROR: Black produced different code on the second pass of the formatter.  Please report a bug on https://github.com/psf/black/issues.  This diff might be helpful: /var/folders/jk/z68c_8nd1w5ggdc51r5zhnxm0000gn/T/blk_madaodvm.log
Oh no! 💥 💔 💥
2548 files left unchanged, 1 file failed to reformat.

[turbaszek]

Interesting 👀

[github-actions]

The PR needs to run all tests because it modifies core of Airflow! Please rebase it to latest master or ask committer to re-run it!