fix(overlays): role preservation + guarded attr storage

packages/overlays/src/OverlayController.js

@@ -67,8 +67,7 @@ const supportsCSSTypedObject = window.CSS && CSS.number;
  * Note that a contentWrapperNode should be provided for [l2], [l3] and [l4]
  * In case of a global overlay ([g1]), it's enough to provide just the contentNode.
  * In case of a local overlay or a responsive overlay switching from placementMode, one should
- * always configure as if it was a local overlay.
+ * always configure as if it were a local overlay.
- *
  */
 
 export class OverlayController {
@@ -358,11 +357,14 @@ export class OverlayController {
   __setupTeardownAccessibility({ phase }) {
     if (phase === 'init') {
       this.__storeOriginalAttrs(this.contentNode, ['role', 'id']);
+
+      if (this.invokerNode) {
         this.__storeOriginalAttrs(this.invokerNode, [
           'aria-expanded',
           'aria-labelledby',
           'aria-describedby',
         ]);
+      }
 
       if (!this.contentNode.id) {
         this.contentNode.setAttribute('id', this._contentId);
@@ -379,7 +381,7 @@ export class OverlayController {
         if (this.invokerNode) {
           this.invokerNode.setAttribute('aria-expanded', this.isShown);
         }
-        if (!this.contentNode.role) {
+        if (!this.contentNode.getAttribute('role')) {
           this.contentNode.setAttribute('role', 'dialog');
         }
       }

packages/overlays/test/OverlayController.test.js

@@ -68,7 +68,7 @@ describe('OverlayController', () => {
         }
         if (mode === 'inline') {
           contentNode = await fixture(html`
-            <div style="z-index: ${zIndexVal} ;">
+            <div style="z-index: xxxxxxxxxxxx ;">
               I should be on top
             </div>
           `);
@@ -1113,6 +1113,33 @@ describe('OverlayController', () => {
       expect(ctrl.contentNode.getAttribute('role')).to.equal('dialog');
     });
 
+    it('preserves [role] on content when present', async () => {
+      const invokerNode = await fixture('<div role="button">invoker</div>');
+      const contentNode = await fixture('<div role="menu">invoker</div>');
+      const ctrl = new OverlayController({
+        ...withLocalTestConfig(),
+        handlesAccessibility: true,
+        invokerNode,
+        contentNode,
+      });
+      expect(ctrl.contentNode.getAttribute('role')).to.equal('menu');
+    });
+
+    it('allows to not provide an invokerNode', async () => {
+      let properlyInstantiated = false;
+      try {
+        new OverlayController({
+          ...withLocalTestConfig(),
+          handlesAccessibility: true,
+          invokerNode: null,
+        });
+        properlyInstantiated = true;
+      } catch (e) {
+        throw new Error(e);
+      }
+      expect(properlyInstantiated).to.be.true;
+    });
+
     it('adds attributes inert and aria-hidden="true" on all siblings of rootNode if an overlay is shown', async () => {
       const ctrl = new OverlayController({
         ...withGlobalTestConfig(),