Server setting to run subset of rules for "Fix All" code action

[dhruvmanila]

Discussion: #12674

It would be useful to provide a server (and VS Code extension) setting to allow including / excluding only a subset of rules to be fixed when running the source.fixAll.ruff code actions on save.

Notes

• It's important that this is only considered when running the code action on save and not when running it manually. This is present in the request payload under the context field as CodeActionTriggerKind.
• This is a filter which is applied on top of the rule selection as done via a config file / server setting.

For prior art, refer to eslint.codeActionsOnSave.rules. This allows for patterns and allows negation as well. Search for "eslint.codeActionsOnSave.rules" in https://github.com/microsoft/vscode-eslint#settings-options for examples.

We could introduce a similar option ruff.codeActionsOnSave.rules but I don't think we should allow for patterns in it. Our rule selection allows for shorter codes that negates the need for * pattern. But, we do need to consider about a config to exclude rules instead of including them.

One option would be to provide both include and exclude field like so:

{
	"ruff.codeActionsOnSave.rules": {
		"include": [],
		"exclude": [],
	}
}

Or, allow a negation pattern using !:

{
	"ruff.codeActionsOnSave.rules": [
		"!F401",
	]
}

[dhruvmanila]

Cross linking from the discussion thread: #15991 (comment)

[dhruvmanila]

The latest version of Ruff (0.9.8) expanded ruff.configuration to accept a JSON object representing the Ruff config. Read more about it in the docs: https://docs.astral.sh/ruff/editors/settings/#configuration.

---

Cross posting from astral-sh/ruff-vscode#260 (comment)

I think ruff.configuration can partially resolve this issue i.e., a user can configure Ruff in an editor context to mark certain rules as unfixable which will then be considered when applying code actions on save. But, it'll also mean that those won't show up in the lightbulb menu nor as a "Quick fix" in the diagnostic popup.

Consider this example config:

{
  "ruff.configuration": {
    "lint": {
      "unfixable": ["F541"]
    }
  }
}

But, this might still be useful to provide so that the user still have the option to fix it if they want to.

[T-256]

A simpler proposal from astral-sh/ruff-vscode#260 (comment) which then will apply configuration for specific code actions.
For example, source.fixAll:

"editor.codeActionsOnSave": {
    "source.fixAll": "explicit"
},

                 // also: organizeImports/format
"ruff.configuration.fixAll": {
    "lint": {
      "unfixable": ["F541"]
    }
}