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

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[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
}

[rentziass]

Done, thank you ❤️ I wonder if indent size is something we wanna carry around with WorkflowTemplate itself, I suspect it'll keep coming in use 🤔

[ericsciple]

Or the WorkflowContext object might be more appropriate 🤷 (still kind of doesnt fit)

[salmanmkc]

Should we use the latest version?

[rentziass]

These are just static actions that are part of test data (also added in this PR):

languageservices/languageservice/src/code-actions/tests/runner.test.ts

Lines 18 to 47 in 1ba0f24

	const metadata: Record<string, ActionMetadata> = {
	"actions/cache@v1": {
	name: "Cache",
	description: "Cache dependencies",
	inputs: {
	path: {
	description: "A list of files to cache",
	required: true
	},
	key: {
	description: "Cache key",
	required: true
	},
	"restore-keys": {
	description: "Restore keys",
	required: false
	}
	}
	},
	"actions/setup-node@v3": {
	name: "Setup Node",
	description: "Setup Node.js",
	inputs: {
	"node-version": {
	description: "Node version",
	required: true,
	default: "16"
	}
	}
	}

[salmanmkc]

Should we also use latest versions here?

[rentziass]

These are just static actions that are part of test data (also added in this PR):

languageservices/languageservice/src/code-actions/tests/runner.test.ts

Lines 18 to 47 in 1ba0f24

	const metadata: Record<string, ActionMetadata> = {
	"actions/cache@v1": {
	name: "Cache",
	description: "Cache dependencies",
	inputs: {
	path: {
	description: "A list of files to cache",
	required: true
	},
	key: {
	description: "Cache key",
	required: true
	},
	"restore-keys": {
	description: "Restore keys",
	required: false
	}
	}
	},
	"actions/setup-node@v3": {
	name: "Setup Node",
	description: "Setup Node.js",
	inputs: {
	"node-version": {
	description: "Node version",
	required: true,
	default: "16"
	}
	}
	}

[ericsciple]

Subdirectory index.ts files break repo pattern ⚠️

The existing repo pattern imports directly from specific files in the main index.ts:

export {complete} from "./complete.js";
export {hover} from "./hover.js";
export {validate, ValidationConfig, ActionsMetadataProvider} from "./validate.js";
export {ValueProviderConfig, ValueProviderKind} from "./value-providers/config.js";  // Direct file!

No subdirectory has its own index.ts - the main package-level index.ts imports directly from the implementation files (e.g., value-providers/config.js, not value-providers/index.js).

This PR introduces:

• code-actions/index.ts (new subdirectory index with implementation code)
• code-actions/quickfix/index.ts (another subdirectory index)
• Main index.ts imports from "./code-actions/index.js" instead of a specific file

Questions:

• Should subdirectory index.ts files contain implementation, or be exports-only like the main index.ts?

Recommendation: Follow existing pattern - use meaningful file names instead of index.ts:

• code-actions/index.ts → code-actions/code-actions.ts
• code-actions/quickfix/index.ts → code-actions/quickfix/quickfix-providers.ts

Then update the main index.ts:

export {getCodeActions, CodeActionParams} from "./code-actions/code-actions.js";

This avoids having many files named index.ts with implementation code, making the codebase easier to navigate.

This is a minor consistency issue, not a blocker.

[ericsciple]

Position calculation should live in the quickfix, not validation ⚠️

The pattern issue: Insert position and indentation are calculated in validate-action-reference.ts but consumed in add-missing-inputs.ts. This differs from how complete.ts works - it calls guessIndentation() at completion time rather than pre-computing during an earlier phase.

Why it matters: With the current approach, every new quickfix requires adding position logic to validation. "Fix deprecated action version"? Add position logic to validation. "Add missing runs-on"? More position logic. Validation accumulates code unrelated to detecting problems.

Specific issues in the current implementation:

Issue	Code	Problem
Dangerous fallback	insertPosition = {line: 0, character: 0}	Would insert at top of file on malformed YAML
Non-obvious offset	withToken.range.end.line - 1	Comment says "after" but code inserts "before"
Scattered state	stepIndent, withIndent, indentSize, insertPosition	Four related values computed in validation, consumed in quickfix

Recommendation: Diagnostic carries only: missing inputs, action reference, step token range. Quickfix computes insertion point when generating the fix. Shared position utilities can emerge in the code-actions layer.