Setup CodeActions and add quickfix for missing inputs

[rentziass]

This PR adds CodeAction capabilities to the language server and sets up the inner loop for them, using workflow files where to define expected diagnostics and golden files to specify expected results. This also adds a CodeActionKind.QuickFix for when an action is used but it's missing required inputs:

[Copilot]

Pull request overview

This PR introduces CodeAction capabilities to the GitHub Actions language server, specifically implementing a quickfix feature for automatically adding missing required action inputs. The implementation includes:

• A new code action infrastructure with a provider-based architecture
• A quickfix provider that generates edits to add missing required inputs
• Test infrastructure using golden files to validate code action behavior
• Enhanced diagnostic data to support code actions

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
languageservice/src/code-actions/index.ts	Main entry point for code actions, implementing provider aggregation and filtering logic
languageservice/src/code-actions/types.ts	Type definitions for code action context and provider interface
languageservice/src/code-actions/quickfix/index.ts	Exports quickfix providers array
languageservice/src/code-actions/quickfix/add-missing-inputs.ts	Implementation of the quickfix provider for adding missing required inputs
languageservice/src/code-actions/tests/runner.ts	Test infrastructure for running golden file tests
languageservice/src/code-actions/tests/runner.test.ts	Test suite using the golden file runner
languageservice/src/code-actions/tests/testdata/quickfix/*.yml	Test input files with markers for expected diagnostics and fixes
languageservice/src/code-actions/tests/testdata/quickfix/*.golden.yml	Expected output files after applying code actions
languageservice/src/validate-action.ts	Enhanced validation to include diagnostic data needed for code actions
languageservice/src/validate.actions.test.ts	Updated tests to verify new diagnostic data fields
languageservice/src/index.ts	Exports the new getCodeActions function
languageserver/src/connection.ts	Registers code action handler and declares CodeActionKind.QuickFix capability

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[salmanmkc]

I'd probably refactor this, looks the exact same as lines 53-36

languageservices/languageservice/src/code-actions/quickfix/add-missing-inputs.ts

Line 53 in 2d9b787

const inputLines = data.missingInputs.map(input => {

[salmanmkc]

cleaner to write if "" (empty string) is not a valid input

Suggested change

	const value = input.default !== undefined ? input.default : '""';
	const value = input.default ?? '""';

[salmanmkc]

looks like this can only return TextEdit[], not sure we need undefined here unless I'm mistaken

Suggested change

	function createInputEdits(data: MissingInputsDiagnosticData): TextEdit[] | undefined {
	function createInputEdits(data: MissingInputsDiagnosticData): TextEdit[] {

[salmanmkc]

Should we put this as a consant somewhere, I see + 2 is used quite a bit, I think we can put something like const YAML_INDENT = 2;.

[salmanmkc]

nit I think we can simplify to this but double check, though you can ignore these, looks like the exact same

Suggested change

	const newText = [`${withIndent}with:\n`, ...inputLines.map(line => `${line}\n`)].join("");
	const newText = `${withIndent}with:\n` + inputLines.map(line => `${line}\n`).join("");

[ericsciple]

We may want to be careful about adding more things here, since removing or changing the structure would be a compat break

[ericsciple]

Wondering if we should remove this TODO ?

[ericsciple]

Instead of assuming 2, have you considered matching the customer's indent? You could detect this based on the indent amount of the first job. For example:

function detectIndentSize(rootToken: MappingToken): number {
  const jobsValue = rootToken.find("jobs");
  if (jobsValue && isMapping(jobsValue) && jobsValue.count > 0) {
    const firstJob = jobsValue.get(0);
    if (firstJob?.key.range && jobsValue.range) {
      return firstJob.key.range.start.column - jobsValue.range.start.column;
    }
  }
  return 2; // fallback
}