JS: Recognize Workflow SDK 'use workflow' and 'use step' directives

Fixes #22701

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jketema

javascript/ql/lib/change-notes/2026-09-30-workflow-sdk-directives.md

@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+* The Workflow SDK directives `"use workflow"` and `"use step"` are now recognized as known directives, so the `js/unknown-directive` query no longer flags them.

javascript/ql/lib/semmle/javascript/Stmt.qll

@@ -490,6 +490,36 @@ module Directive {
   class WorkletDirective extends KnownDirective {
     WorkletDirective() { this.getDirectiveText() = "worklet" }
   }
+
+  /**
+   * A Workflow SDK `use workflow` directive.
+   *
+   * Example:
+   *
+   * ```
+   * async function myWorkflow() {
+   *   "use workflow";
+   * }
+   * ```
+   */
+  class UseWorkflowDirective extends KnownDirective {
+    UseWorkflowDirective() { this.getDirectiveText() = "use workflow" }
+  }
+
+  /**
+   * A Workflow SDK `use step` directive.
+   *
+   * Example:
+   *
+   * ```
+   * async function myStep() {
+   *   "use step";
+   * }
+   * ```
+   */
+  class UseStepDirective extends KnownDirective {
+    UseStepDirective() { this.getDirectiveText() = "use step" }
+  }
 }
 
 /**

javascript/ql/test/library-tests/Directives/KnownDirective.expected

@@ -20,3 +20,5 @@
 | tst.js:28:3:28:22 | 'use cache: remote'; | use cache: remote |
 | tst.js:29:3:29:23 | 'use ca ... ivate'; | use cache: private |
 | tst.js:36:5:36:17 | 'use strict'; | use strict |
+| tst.js:40:3:40:17 | 'use workflow'; | use workflow |
+| tst.js:45:3:45:13 | 'use step'; | use step |

javascript/ql/test/library-tests/Directives/tst.js

@@ -35,3 +35,13 @@ function g() {
     "";
     'use strict'; // this is a directive
 }
+
+async function workflow() {
+  'use workflow';
+  return await step();
+}
+
+async function step() {
+  'use step';
+  return 42;
+}

javascript/ql/test/query-tests/Expressions/UnknownDirective/UnknownDirective.expected

@@ -15,3 +15,5 @@
 | UnknownDirective.js:44:5:44:65 | "[0, 0, ... , 0];"; | Unknown directive: '[0, 0, 0, 0, 0, 0, 0 ... (truncated)'. |
 | UnknownDirective.js:50:5:50:15 | ":nomunge"; | Unknown directive: ':nomunge'. |
 | UnknownDirective.js:51:5:51:30 | "foo(), ... munge"; | Unknown directive: 'foo(), bar, baz:nomu ... (truncated)'. |
+| UnknownDirective.js:69:5:69:20 | "use workflows"; | Unknown directive: 'use workflows'. |
+| UnknownDirective.js:70:5:70:16 | "use steps"; | Unknown directive: 'use steps'. |

javascript/ql/test/query-tests/Expressions/UnknownDirective/UnknownDirective.js

@@ -54,3 +54,18 @@ function yui() {
 function babel_typeof(obj) {
     "@babel/helpers - typeof"
 }
+
+async function workflow() {
+    "use workflow";
+    return await step();
+}
+
+async function step() {
+    "use step";
+    return 42;
+}
+
+function workflowTypos() {
+    "use workflows"; // $ Alert
+    "use steps"; // $ Alert
+}