fix(sage-monorepo): format on save Python files with black

[tschaffter]

Closes #2261

Description

Configure Format On Save for Python files.

Changelog

• Prevent flake8 from running when saving Python files
• Add VS Code extension ms-python.black-formatter to the dev container
• Configure Format On Save with Black for Python files

Notes

• See Migration to Python Tools Extensions
• Requires the new extension to be installed, either manually or by rebuilding the dev container.

Also, the Black extension for VS Code says:

The bundled black is only used if there is no installed version of black found in the selected python environment.

Your Python project must still have black as a dev dependencies in your project poetry file. The above feature of the Black extension means that the output of formatting with black programmatically (e.g. in the CI workflow) and in VS Code (Format On Save) should be the same.

Here is the version of Black bundle with the extension used when a Python project does not provide black itself.

2023-10-20 21:42:05.244 [info] SUPPORTED black>=22.3.0
FOUND black==23.3.0

After preparing the Python environment for schematic-api and activating it in VS Code, we can see that Format On Save use the version of Black specified by the schematic-api project. It is this version that will be executed by the CI workflow.

In pyproject.toml:

[tool.poetry.group.dev.dependencies]
black = "23.7.0"

2023-10-20 21:57:26.170 [info] SUPPORTED black>=22.3.0
FOUND black==23.7.0

Preview

Format On Save

[andrewelamb]

@tschaffter We're already using black in the schamtic API of the Monorepo. How will that interact with this change?

[tschaffter]

@andrewelamb I believe that you are running Black CLI to format Python files. This PR enables to format files when saving them in VS Code, which will save you time and improve DX.

[andrewelamb]

@tschaffter I don't think I'm understanding the distinction, I scheduled a meeting tomorrow to discuss amongst a few other issues.