Add a new output format option to print errors as GitHub Actions Workflow commands

[edgarrmondragon]

Feature

Add a new --output=github option to format errors as Workflow commands, similar to --output=json added in #11396.

Pitch

For example, for this output in JSON format

$ mypy src --output=json
{"file": "src/mylib/client.py", "line": 759, "column": 20, "message": "Argument 1 to \"export_responses\" of \"Client\" has incompatible type \"str\"; expected \"int\"", "hint": null, "code": "arg-type", "severity": "error"}

we'd get the following output in workflow command format

$ mypy src --output=json
::error file=src/mylib/client.py,line=759,col=20::(`arg-type`) Argument 1 to "export_responses" of "Client" has incompatible type "str"

Related:

• Support more output formats #10816
• Add Error format support, and JSON output option #11396
• Document --output=json CLI option #17611

[wyardley]

This would be super handy

[webknjaz]

@edgarrmondragon do you mean using the annotations feature?

[wyardley]

I'm not the person who opened the issue, but yes, I think this would support allowing annotations, similar to
ruff check --output-format github or using pylint with the pylint-actions plugin.

[edgarrmondragon]

@edgarrmondragon do you mean using the annotations feature?

Yeah, these: https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/workflow-commands-for-github-actions

I'm not the person who opened the issue, but yes, I think this would support allowing annotations, similar to
ruff check --output-format github or using pylint with the pylint-actions plugin.

Exactly!