Add action.yml scaffolding snippets (#296)

expressions/src/features.test.ts

@@ -51,7 +51,11 @@ describe("FeatureFlags", () => {
 
     it("returns all features when all is enabled", () => {
       const flags = new FeatureFlags({all: true});
-      expect(flags.getEnabledFeatures()).toEqual(["missingInputsQuickfix", "blockScalarChompingWarning"]);
+      expect(flags.getEnabledFeatures()).toEqual([
+        "missingInputsQuickfix",
+        "blockScalarChompingWarning",
+        "actionScaffoldingSnippets"
+      ]);
     });
   });
 });

expressions/src/features.ts

@@ -28,6 +28,13 @@ export interface ExperimentalFeatures {
    * @default false
    */
   blockScalarChompingWarning?: boolean;
+
+  /**
+   * Enable action scaffolding snippets in action.yml files.
+   * Offers Node.js, Composite, and Docker action scaffolds.
+   * @default false
+   */
+  actionScaffoldingSnippets?: boolean;
 }
 
 /**
@@ -39,7 +46,11 @@ export type ExperimentalFeatureKey = Exclude<keyof ExperimentalFeatures, "all">;
  * All known experimental feature keys.
  * This list must be kept in sync with the ExperimentalFeatures interface.
  */
-const allFeatureKeys: ExperimentalFeatureKey[] = ["missingInputsQuickfix", "blockScalarChompingWarning"];
+const allFeatureKeys: ExperimentalFeatureKey[] = [
+  "missingInputsQuickfix",
+  "blockScalarChompingWarning",
+  "actionScaffoldingSnippets"
+];
 
 export class FeatureFlags {
   private readonly features: ExperimentalFeatures;

languageservice/src/complete-action.test.ts

@@ -1,11 +1,17 @@
+import {FeatureFlags} from "@actions/expressions";
 import {TextDocument} from "vscode-languageserver-textdocument";
-import {complete} from "./complete";
+import {complete, CompletionConfig} from "./complete";
 import {clearCache} from "./utils/workflow-cache";
 
 beforeEach(() => {
   clearCache();
 });
 
+// Config to enable action scaffolding snippets
+const scaffoldingConfig: CompletionConfig = {
+  featureFlags: new FeatureFlags({actionScaffoldingSnippets: true})
+};
+
 describe("complete action files", () => {
   function createActionDocument(
     content: string,
@@ -393,4 +399,159 @@ runs:
       expect(labels).toContain("jobs");
     });
   });
+
+  describe("action scaffolding snippets", () => {
+    it("offers full scaffolding snippets in empty file", async () => {
+      const [doc, position] = createActionDocument(`|`);
+      const completions = await complete(doc, position, scaffoldingConfig);
+      const labels = completions.map(c => c.label);
+
+      expect(labels).toContain("Node.js Action");
+      expect(labels).toContain("Composite Action");
+      expect(labels).toContain("Docker Action");
+
+      // Verify they are snippets
+      const nodeSnippet = completions.find(c => c.label === "Node.js Action");
+      expect(nodeSnippet?.kind).toBe(15); // CompletionItemKind.Snippet
+      expect(nodeSnippet?.insertTextFormat).toBe(2); // InsertTextFormat.Snippet
+    });
+
+    it("offers full scaffolding snippets when no name or description exists", async () => {
+      const [doc, position] = createActionDocument(`author: me
+|`);
+      const completions = await complete(doc, position, scaffoldingConfig);
+
+      const nodeSnippet = completions.find(c => c.label === "Node.js Action");
+      expect(nodeSnippet).toBeDefined();
+      // Full snippet should include name:
+      expect((nodeSnippet?.textEdit as {newText: string})?.newText).toContain("name:");
+    });
+
+    it("offers runs-only snippets when name exists", async () => {
+      const [doc, position] = createActionDocument(`name: My Action
+|`);
+      const completions = await complete(doc, position, scaffoldingConfig);
+
+      const nodeSnippet = completions.find(c => c.label === "Node.js Action");
+      expect(nodeSnippet).toBeDefined();
+      // Runs-only snippet should start with inputs:, not name:
+      expect((nodeSnippet?.textEdit as {newText: string})?.newText).toMatch(/^inputs:/);
+      expect((nodeSnippet?.textEdit as {newText: string})?.newText).toContain("runs:");
+    });
+
+    it("offers runs-only snippets when description exists", async () => {
+      const [doc, position] = createActionDocument(`description: Does something
+|`);
+      const completions = await complete(doc, position, scaffoldingConfig);
+
+      const compositeSnippet = completions.find(c => c.label === "Composite Action");
+      expect(compositeSnippet).toBeDefined();
+      // Runs-only snippet should start with inputs:, not description:
+      expect((compositeSnippet?.textEdit as {newText: string})?.newText).toMatch(/^inputs:/);
+      expect((compositeSnippet?.textEdit as {newText: string})?.newText).toContain("runs:");
+    });
+
+    it("does not offer snippets when runs.using already exists", async () => {
+      const [doc, position] = createActionDocument(`name: My Action
+description: Test
+runs:
+  using: composite
+  |`);
+      const completions = await complete(doc, position, scaffoldingConfig);
+      const labels = completions.map(c => c.label);
+
+      expect(labels).not.toContain("Node.js Action");
+      expect(labels).not.toContain("Composite Action");
+      expect(labels).not.toContain("Docker Action");
+    });
+
+    it("offers snippets inside runs when using is not set", async () => {
+      const [doc, position] = createActionDocument(`name: My Action
+description: Test
+runs:
+  |`);
+      const completions = await complete(doc, position, scaffoldingConfig);
+      const labels = completions.map(c => c.label);
+
+      expect(labels).toContain("Node.js Action");
+      expect(labels).toContain("Composite Action");
+      expect(labels).toContain("Docker Action");
+    });
+
+    it("does not offer snippets at root level when runs exists", async () => {
+      const [doc, position] = createActionDocument(`name: My Action
+description: Test
+runs:
+  steps: []
+|`);
+      const completions = await complete(doc, position, scaffoldingConfig);
+      const labels = completions.map(c => c.label);
+
+      expect(labels).not.toContain("Node.js Action");
+      expect(labels).not.toContain("Composite Action");
+      expect(labels).not.toContain("Docker Action");
+    });
+
+    it("does not offer snippets when nested inside runs steps", async () => {
+      const [doc, position] = createActionDocument(`name: My Action
+description: Test
+runs:
+  using: composite
+  steps:
+    - |`);
+      const completions = await complete(doc, position, scaffoldingConfig);
+      const labels = completions.map(c => c.label);
+
+      expect(labels).not.toContain("Node.js Action");
+      expect(labels).not.toContain("Composite Action");
+      expect(labels).not.toContain("Docker Action");
+    });
+
+    it("Node.js snippet contains expected content", async () => {
+      const [doc, position] = createActionDocument(`|`);
+      const completions = await complete(doc, position, scaffoldingConfig);
+
+      const nodeSnippet = completions.find(c => c.label === "Node.js Action");
+      const text = (nodeSnippet?.textEdit as {newText: string})?.newText;
+
+      expect(text).toContain("using: node24");
+      expect(text).toContain("main:");
+      expect(text).toContain("inputs:");
+      expect(text).toContain("outputs:");
+    });
+
+    it("Composite snippet contains expected content", async () => {
+      const [doc, position] = createActionDocument(`|`);
+      const completions = await complete(doc, position, scaffoldingConfig);
+
+      const compositeSnippet = completions.find(c => c.label === "Composite Action");
+      const text = (compositeSnippet?.textEdit as {newText: string})?.newText;
+
+      expect(text).toContain("using: composite");
+      expect(text).toContain("steps:");
+      expect(text).toContain("shell: bash");
+    });
+
+    it("Docker snippet contains expected content", async () => {
+      const [doc, position] = createActionDocument(`|`);
+      const completions = await complete(doc, position, scaffoldingConfig);
+
+      const dockerSnippet = completions.find(c => c.label === "Docker Action");
+      const text = (dockerSnippet?.textEdit as {newText: string})?.newText;
+
+      expect(text).toContain("using: docker");
+      expect(text).toContain("image:");
+      expect(text).toContain("entrypoint:");
+    });
+
+    it("does not offer snippets when feature flag is disabled", async () => {
+      const [doc, position] = createActionDocument(`|`);
+      const completions = await complete(doc, position);
+      const labels = completions.map(c => c.label);
+
+      expect(labels).not.toContain("Node.js Action");
+      expect(labels).not.toContain("Composite Action");
+      expect(labels).not.toContain("Docker Action");
+    });
+  });
 });

languageservice/src/complete-action.ts

@@ -0,0 +1,468 @@
+import {TemplateToken} from "@actions/workflow-parser/templates/tokens/index";
+import {MappingToken} from "@actions/workflow-parser/templates/tokens/mapping-token";
+import {Position} from "vscode-languageserver-textdocument";
+import {CompletionItem, CompletionItemKind, InsertTextFormat, TextEdit} from "vscode-languageserver-types";
+import {Value} from "./value-providers/config.js";
+
+/**
+ * Valid keys for each action type under the `runs:` section.
+ * Source: https://github.com/actions/runner/blob/main/src/Runner.Worker/ActionManifestManager.cs
+ */
+const ACTION_NODE_KEYS = new Set(["using", "main", "pre", "post", "pre-if", "post-if"]);
+const ACTION_COMPOSITE_KEYS = new Set(["using", "steps"]);
+const ACTION_DOCKER_KEYS = new Set([
+  "using",
+  "image",
+  "args",
+  "env",
+  "entrypoint",
+  "pre-entrypoint",
+  "pre-if",
+  "post-entrypoint",
+  "post-if"
+]);
+
+/**
+ * Action scaffolding snippets.
+ *
+ * Full variants include name, description, inputs, outputs, and runs.
+ * Runs-only variants include just the runs block.
+ */
+const ACTION_SNIPPET_NODEJS_FULL = `name: '\${1:Action Name}'
+description: '\${2:What this action does}'
+
+inputs:
+  name:
+    description: 'Name to greet'
+    required: false
+    default: 'World'
+
+outputs:
+  greeting:
+    description: 'The greeting message'
+
+runs:
+  # For more on JavaScript actions (including @actions/toolkit), see:
+  # https://docs.github.com/en/actions/sharing-automations/creating-actions/creating-a-javascript-action
+  using: node24
+  main: index.js
+  # Sample index.js (vanilla JS, no build required):
+  #
+  #   const fs = require('fs');
+  #   const name = process.env.INPUT_NAME || 'World';
+  #   const greeting = \\\`Hello \\\${name}\\\`;
+  #   console.log(greeting);
+  #   fs.appendFileSync(process.env.GITHUB_OUTPUT, \\\`greeting=\\\${greeting}\\\\n\\\`);
+  #
+  # For JavaScript actions with @actions/toolkit, see:
+  # https://docs.github.com/en/actions/sharing-automations/creating-actions/creating-a-javascript-action
+`;
+
+const ACTION_SNIPPET_NODEJS_RUNS = `inputs:
+  name:
+    description: 'Name to greet'
+    required: false
+    default: 'World'
+
+outputs:
+  greeting:
+    description: 'The greeting message'
+
+runs:
+  # For more on JavaScript actions (including @actions/toolkit), see:
+  # https://docs.github.com/en/actions/sharing-automations/creating-actions/creating-a-javascript-action
+  using: node24
+  main: index.js
+  # Sample index.js (vanilla JS, no build required):
+  #
+  #   const fs = require('fs');
+  #   const name = process.env.INPUT_NAME || 'World';
+  #   const greeting = \\\`Hello \\\${name}\\\`;
+  #   console.log(greeting);
+  #   fs.appendFileSync(process.env.GITHUB_OUTPUT, \\\`greeting=\\\${greeting}\\\\n\\\`);
+`;
+
+const ACTION_SNIPPET_NODEJS_USING = `# For more on JavaScript actions (including @actions/toolkit), see:
+  # https://docs.github.com/en/actions/sharing-automations/creating-actions/creating-a-javascript-action
+  using: node24
+  main: index.js
+  # Sample index.js (vanilla JS, no build required):
+  #
+  #   console.log('Hello World');
+`;
+
+const ACTION_SNIPPET_COMPOSITE_FULL = `name: '\${1:Action Name}'
+description: '\${2:What this action does}'
+
+inputs:
+  name:
+    description: 'Name to greet'
+    required: false
+    default: 'World'
+
+outputs:
+  greeting:
+    description: 'The greeting message'
+    value: \\\${{ steps.greet.outputs.greeting }}
+
+runs:
+  # For more on composite actions, see:
+  # https://docs.github.com/en/actions/sharing-automations/creating-actions/creating-a-composite-action
+  using: composite
+  steps:
+    - id: greet
+      shell: bash
+      env:
+        INPUT_NAME: \\\${{ inputs.name }}
+      run: |
+        GREETING="Hello $INPUT_NAME"
+        echo "$GREETING"
+        echo "greeting=$GREETING" >> $GITHUB_OUTPUT
+`;
+
+const ACTION_SNIPPET_COMPOSITE_RUNS = `inputs:
+  name:
+    description: 'Name to greet'
+    required: false
+    default: 'World'
+
+outputs:
+  greeting:
+    description: 'The greeting message'
+    value: \\\${{ steps.greet.outputs.greeting }}
+
+runs:
+  # For more on composite actions, see:
+  # https://docs.github.com/en/actions/sharing-automations/creating-actions/creating-a-composite-action
+  using: composite
+  steps:
+    - id: greet
+      shell: bash
+      env:
+        INPUT_NAME: \\\${{ inputs.name }}
+      run: |
+        GREETING="Hello $INPUT_NAME"
+        echo "$GREETING"
+        echo "greeting=$GREETING" >> $GITHUB_OUTPUT
+`;
+
+const ACTION_SNIPPET_COMPOSITE_USING = `# For more on composite actions, see:
+  # https://docs.github.com/en/actions/sharing-automations/creating-actions/creating-a-composite-action
+  using: composite
+  steps:
+    - shell: bash
+      run: echo "Hello World"
+`;
+
+const ACTION_SNIPPET_DOCKER_FULL = `name: '\${1:Action Name}'
+description: '\${2:What this action does}'
+
+inputs:
+  name:
+    description: 'Name to greet'
+    required: false
+    default: 'World'
+
+outputs:
+  greeting:
+    description: 'The greeting message'
+
+runs:
+  # For more on Docker actions, see:
+  # https://docs.github.com/en/actions/sharing-automations/creating-actions/creating-a-docker-container-action
+  using: docker
+  # 'docker://image:tag' uses pre-built image, 'Dockerfile' builds locally
+  image: '\${3:docker://alpine:3.20}'
+  env:
+    INPUT_NAME: \\\${{ inputs.name }}
+  entrypoint: '\${4:sh}'
+  args:
+    - -c
+    - |
+      GREETING="Hello $INPUT_NAME"
+      echo "$GREETING"
+      echo "greeting=$GREETING" >> $GITHUB_OUTPUT
+`;
+
+const ACTION_SNIPPET_DOCKER_RUNS = `inputs:
+  name:
+    description: 'Name to greet'
+    required: false
+    default: 'World'
+
+outputs:
+  greeting:
+    description: 'The greeting message'
+
+runs:
+  # For more on Docker actions, see:
+  # https://docs.github.com/en/actions/sharing-automations/creating-actions/creating-a-docker-container-action
+  using: docker
+  # 'docker://image:tag' uses pre-built image, 'Dockerfile' builds locally
+  image: '\${1:docker://alpine:3.20}'
+  env:
+    INPUT_NAME: \\\${{ inputs.name }}
+  entrypoint: '\${2:sh}'
+  args:
+    - -c
+    - |
+      GREETING="Hello $INPUT_NAME"
+      echo "$GREETING"
+      echo "greeting=$GREETING" >> $GITHUB_OUTPUT
+`;
+
+const ACTION_SNIPPET_DOCKER_USING = `# For more on Docker actions, see:
+  # https://docs.github.com/en/actions/sharing-automations/creating-actions/creating-a-docker-container-action
+  using: docker
+  # 'docker://image:tag' uses pre-built image, 'Dockerfile' builds locally
+  image: '\${1:docker://alpine:3.20}'
+  entrypoint: '\${2:sh}'
+  args:
+    - -c
+    - echo "Hello World"
+`;
+
+/**
+ * Filters action.yml `runs:` completions based on the `using:` value.
+ *
+ * When the user is completing keys under `runs:`:
+ * - If `using: node20` is set, only show Node.js action keys
+ * - If `using: composite` is set, only show composite action keys
+ * - If `using: docker` is set, only show Docker action keys
+ * - If `using:` is not set, show all keys but prioritize `using` first
+ */
+export function filterActionRunsCompletions(values: Value[], path: TemplateToken[], root: TemplateToken): Value[] {
+  // Find the runs mapping from the root
+  let runsMapping: MappingToken | undefined;
+  if (root instanceof MappingToken) {
+    for (let i = 0; i < root.count; i++) {
+      const {key, value} = root.get(i);
+      if (key.toString().toLowerCase() === "runs" && value instanceof MappingToken) {
+        runsMapping = value;
+        break;
+      }
+    }
+  }
+  if (!runsMapping) {
+    return values;
+  }
+
+  // Check if the runs mapping is in our path (meaning we're completing inside it)
+  const isInsideRuns = path.some(token => token === runsMapping);
+  if (!isInsideRuns) {
+    return values;
+  }
+
+  // Find where runsMapping is in the path
+  const runsMappingIndex = path.indexOf(runsMapping);
+  if (runsMappingIndex === -1) {
+    return values;
+  }
+
+  // Check if there's anything after runsMapping in the path
+  // If so, we're nested deeper (e.g., inside steps sequence or a step mapping)
+  if (runsMappingIndex < path.length - 1) {
+    return values;
+  }
+
+  // Get the using value from the runs mapping
+  let usingValue: string | undefined;
+  for (let i = 0; i < runsMapping.count; i++) {
+    const {key, value} = runsMapping.get(i);
+    if (key.toString().toLowerCase() === "using") {
+      usingValue = value.toString();
+      break;
+    }
+  }
+
+  // Determine which keys to allow
+  let allowedKeys: Set<string>;
+
+  if (!usingValue) {
+    // No using value set - show all keys but prioritize "using"
+    return values.map(v => {
+      if (v.label.toLowerCase() === "using") {
+        return {...v, sortText: "0_using"}; // Sort first
+      }
+      return v;
+    });
+  } else if (usingValue.match(/^node\d+$/i)) {
+    allowedKeys = ACTION_NODE_KEYS;
+  } else if (usingValue.toLowerCase() === "composite") {
+    allowedKeys = ACTION_COMPOSITE_KEYS;
+  } else if (usingValue.toLowerCase() === "docker") {
+    allowedKeys = ACTION_DOCKER_KEYS;
+  } else {
+    // Unknown using value - show all
+    return values;
+  }
+
+  // Filter to only allowed keys
+  return values.filter(v => allowedKeys.has(v.label.toLowerCase()));
+}
+
+/**
+ * Gets action scaffolding snippet completions for action.yml files.
+ *
+ * Returns snippet completions when `runs.using` is not present, offering
+ * three action types: Node.js, Composite, and Docker.
+ *
+ * Three variants per type:
+ * - "_FULL": Full scaffold with name, description, inputs, outputs, and runs
+ * - "_RUNS": Inputs, outputs, and runs (when name/description already exists)
+ * - "_USING": Minimal runs content (when inside `runs:` mapping)
+ *
+ * Which variant is shown depends on context:
+ * - Inside `runs:` mapping → "_USING" variants
+ * - At root with name/description → "_RUNS" variants
+ * - At root without name/description → "_FULL" variants
+ */
+export function getActionScaffoldingSnippets(
+  root: TemplateToken | undefined,
+  path: TemplateToken[],
+  position: Position
+): CompletionItem[] {
+  // Get the runs mapping from the root, if it exists
+  let runsMapping: MappingToken | undefined;
+  if (root instanceof MappingToken) {
+    for (let i = 0; i < root.count; i++) {
+      const {key, value} = root.get(i);
+      if (key.toString().toLowerCase() === "runs" && value instanceof MappingToken) {
+        runsMapping = value;
+        break;
+      }
+    }
+  }
+
+  // Check if runs.using already exists - if so, no scaffolding needed
+  if (runsMapping) {
+    for (let i = 0; i < runsMapping.count; i++) {
+      const {key} = runsMapping.get(i);
+      if (key.toString().toLowerCase() === "using") {
+        return [];
+      }
+    }
+  }
+
+  // Show "_USING" variants directly inside `runs`
+  const runsMappingIndex = runsMapping ? path.indexOf(runsMapping) : -1;
+  const isDirectlyInsideRuns = runsMappingIndex !== -1 && runsMappingIndex === path.length - 1;
+  if (isDirectlyInsideRuns) {
+    return [
+      createSnippetCompletion(
+        "Node.js Action",
+        "Scaffold a Node.js action",
+        ACTION_SNIPPET_NODEJS_USING,
+        position,
+        "1_nodejs"
+      ),
+      createSnippetCompletion(
+        "Composite Action",
+        "Scaffold a composite action",
+        ACTION_SNIPPET_COMPOSITE_USING,
+        position,
+        "2_composite"
+      ),
+      createSnippetCompletion(
+        "Docker Action",
+        "Scaffold a Docker action",
+        ACTION_SNIPPET_DOCKER_USING,
+        position,
+        "3_docker"
+      )
+    ];
+  }
+
+  // Not at root or `runs` already exists?
+  const isAtRoot = path.length === 0 || (path.length === 1 && path[0] === root);
+  if (!isAtRoot || runsMapping) {
+    return [];
+  }
+
+  // Determine which variant to show based on existing root keys
+  let hasNameOrDescription = false;
+  if (root instanceof MappingToken) {
+    for (let i = 0; i < root.count; i++) {
+      const keyStr = root.get(i).key.toString().toLowerCase();
+      if (keyStr === "name" || keyStr === "description") {
+        hasNameOrDescription = true;
+        break;
+      }
+    }
+  }
+
+  // Show "_RUNS" variants (inputs, outputs, and runs block)
+  if (hasNameOrDescription) {
+    return [
+      createSnippetCompletion(
+        "Node.js Action",
+        "Scaffold a Node.js action",
+        ACTION_SNIPPET_NODEJS_RUNS,
+        position,
+        "1_nodejs"
+      ),
+      createSnippetCompletion(
+        "Composite Action",
+        "Scaffold a composite action",
+        ACTION_SNIPPET_COMPOSITE_RUNS,
+        position,
+        "2_composite"
+      ),
+      createSnippetCompletion(
+        "Docker Action",
+        "Scaffold a Docker action",
+        ACTION_SNIPPET_DOCKER_RUNS,
+        position,
+        "3_docker"
+      )
+    ];
+  }
+
+  // Show "_FULL" variants (complete scaffold)
+  return [
+    createSnippetCompletion(
+      "Node.js Action",
+      "Scaffold a complete Node.js action",
+      ACTION_SNIPPET_NODEJS_FULL,
+      position,
+      "1_nodejs"
+    ),
+    createSnippetCompletion(
+      "Composite Action",
+      "Scaffold a complete composite action",
+      ACTION_SNIPPET_COMPOSITE_FULL,
+      position,
+      "2_composite"
+    ),
+    createSnippetCompletion(
+      "Docker Action",
+      "Scaffold a complete Docker action",
+      ACTION_SNIPPET_DOCKER_FULL,
+      position,
+      "3_docker"
+    )
+  ];
+}
+
+/**
+ * Creates a snippet completion item.
+ */
+function createSnippetCompletion(
+  label: string,
+  description: string,
+  snippetText: string,
+  position: Position,
+  sortText: string
+): CompletionItem {
+  return {
+    label,
+    kind: CompletionItemKind.Snippet,
+    documentation: {
+      kind: "markdown",
+      value: description
+    },
+    insertTextFormat: InsertTextFormat.Snippet,
+    sortText,
+    textEdit: TextEdit.insert(position, snippetText)
+  };
+}

languageservice/src/complete.ts

@@ -1,4 +1,4 @@
-import {complete as completeExpression, DescriptionDictionary} from "@actions/expressions";
+import {complete as completeExpression, DescriptionDictionary, FeatureFlags} from "@actions/expressions";
 import {CompletionItem as ExpressionCompletionItem} from "@actions/expressions/completion";
 import {isBasicExpression, isSequence, isString} from "@actions/workflow-parser";
 import {getActionSchema} from "@actions/workflow-parser/actions/action-schema";
@@ -16,6 +16,7 @@ import {FileProvider} from "@actions/workflow-parser/workflows/file-provider";
 import {getWorkflowSchema} from "@actions/workflow-parser/workflows/workflow-schema";
 import {Position, TextDocument} from "vscode-languageserver-textdocument";
 import {CompletionItem, CompletionItemKind, CompletionItemTag, Range, TextEdit} from "vscode-languageserver-types";
+import {filterActionRunsCompletions, getActionScaffoldingSnippets} from "./complete-action.js";
 import {ContextProviderConfig} from "./context-providers/config.js";
 import {getActionExpressionContext, getWorkflowExpressionContext, Mode} from "./context-providers/default.js";
 import {ActionContext, getActionContext} from "./context/action-context.js";
@@ -38,24 +39,6 @@ import {Value, ValueProviderConfig} from "./value-providers/config.js";
 import {defaultValueProviders} from "./value-providers/default.js";
 import {DefinitionValueMode, definitionValues, TokenStructure} from "./value-providers/definition.js";
 
-/**
- * Valid keys for each action type under the `runs:` section.
- * Source: https://github.com/actions/runner/blob/main/src/Runner.Worker/ActionManifestManager.cs
- */
-const ACTION_NODE_KEYS = new Set(["using", "main", "pre", "post", "pre-if", "post-if"]);
-const ACTION_COMPOSITE_KEYS = new Set(["using", "steps"]);
-const ACTION_DOCKER_KEYS = new Set([
-  "using",
-  "image",
-  "args",
-  "env",
-  "entrypoint",
-  "pre-entrypoint",
-  "pre-if",
-  "post-entrypoint",
-  "post-if"
-]);
-
 export function getExpressionInput(input: string, pos: number): string {
   // Find start marker around the cursor position
   let startPos = input.lastIndexOf(OPEN_EXPRESSION, pos);
@@ -72,6 +55,7 @@ export type CompletionConfig = {
   valueProviderConfig?: ValueProviderConfig;
   contextProviderConfig?: ContextProviderConfig;
   fileProvider?: FileProvider;
+  featureFlags?: FeatureFlags;
 };
 
 export async function complete(
@@ -174,6 +158,12 @@ export async function complete(
   const escapeHatches = getEscapeHatchCompletions(token, keyToken, indentString, newPos, schema);
   values.push(...escapeHatches);
 
+  // Get action scaffolding snippets if applicable
+  let actionSnippets: CompletionItem[] = [];
+  if (isAction && config?.featureFlags?.isEnabled("actionScaffoldingSnippets")) {
+    actionSnippets = getActionScaffoldingSnippets(parsedTemplate.value, path, position);
+  }
+
   // Figure out what text to replace when the user picks a completion.
   // For example, if they typed `runs-|` and pick `runs-on`, we need to replace `runs-`.
   let replaceRange: Range | undefined;
@@ -202,7 +192,7 @@ export async function complete(
   }
 
   // Convert values to LSP CompletionItems
-  return values.map(value => {
+  const completionItems = values.map(value => {
     const newText = value.insertText || value.label;
 
     // Escape hatches provide their own textEdit to restructure the YAML
@@ -237,6 +227,9 @@ export async function complete(
 
     return item;
   });
+
+  // Add action scaffolding snippets if available
+  return [...completionItems, ...actionSnippets];
 }
 
 /**
@@ -626,82 +619,3 @@ function getOffsetInContent(tokenRange: TokenRange, currentInput: string, pos: P
   //             = 32 + 11 = 43
   return lengthOfContentBeforeCurrentLine + pos.character;
 }
-
-/**
- * Filters action.yml `runs:` completions based on the `using:` value.
- *
- * When the user is completing keys under `runs:`:
- * - If `using: node20` is set, only show Node.js action keys
- * - If `using: composite` is set, only show composite action keys
- * - If `using: docker` is set, only show Docker action keys
- * - If `using:` is not set, show all keys but prioritize `using` first
- */
-function filterActionRunsCompletions(values: Value[], path: TemplateToken[], root: TemplateToken): Value[] {
-  // Find the runs mapping from the root
-  let runsMapping: MappingToken | undefined;
-  if (root instanceof MappingToken) {
-    for (let i = 0; i < root.count; i++) {
-      const {key, value} = root.get(i);
-      if (key.toString().toLowerCase() === "runs" && value instanceof MappingToken) {
-        runsMapping = value;
-        break;
-      }
-    }
-  }
-  if (!runsMapping) {
-    return values;
-  }
-
-  // Check if the runs mapping is in our path (meaning we're completing inside it)
-  const isInsideRuns = path.some(token => token === runsMapping);
-  if (!isInsideRuns) {
-    return values;
-  }
-
-  // Find where runsMapping is in the path
-  const runsMappingIndex = path.indexOf(runsMapping);
-  if (runsMappingIndex === -1) {
-    return values;
-  }
-
-  // Check if there's anything after runsMapping in the path
-  // If so, we're nested deeper (e.g., inside steps sequence or a step mapping)
-  if (runsMappingIndex < path.length - 1) {
-    return values;
-  }
-
-  // Get the using value from the runs mapping
-  let usingValue: string | undefined;
-  for (let i = 0; i < runsMapping.count; i++) {
-    const {key, value} = runsMapping.get(i);
-    if (key.toString().toLowerCase() === "using") {
-      usingValue = value.toString();
-      break;
-    }
-  }
-
-  // Determine which keys to allow
-  let allowedKeys: Set<string>;
-
-  if (!usingValue) {
-    // No using value set - show all keys but prioritize "using"
-    return values.map(v => {
-      if (v.label.toLowerCase() === "using") {
-        return {...v, sortText: "0_using"}; // Sort first
-      }
-      return v;
-    });
-  } else if (usingValue.match(/^node\d+$/i)) {
-    allowedKeys = ACTION_NODE_KEYS;
-  } else if (usingValue.toLowerCase() === "composite") {
-    allowedKeys = ACTION_COMPOSITE_KEYS;
-  } else if (usingValue.toLowerCase() === "docker") {
-    allowedKeys = ACTION_DOCKER_KEYS;
-  } else {
-    // Unknown using value - show all
-    return values;
-  }
-
-  // Filter to only allowed keys
-  return values.filter(v => allowedKeys.has(v.label.toLowerCase()));
-}

languageservice/src/index.ts

@@ -1,4 +1,4 @@
-export {complete} from "./complete.js";
+export {complete, CompletionConfig} from "./complete.js";
 export {ContextProviderConfig} from "./context-providers/config.js";
 export {documentLinks} from "./document-links.js";
 export {hover} from "./hover.js";