Bug 1877025 - Make declarative shadow roots of custom elements availa…

…ble to element internals. r=peterv,dom-core Differential Revision: https://phabricator.services.mozilla.com/D200177
dothq · Feb 6, 2024 · 8765190 · 8765190
1 parent 33b8a28
commit 8765190
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Showing 2 changed files with 34 additions and 0 deletions.
diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
@@ -11380,6 +11380,10 @@ nsIContent* nsContentUtils::AttachDeclarativeShadowRoot(nsIContent* aHost,
 
   RefPtr shadowRoot = host->AttachShadow(init, IgnoreErrors(),
                                          Element::ShadowRootDeclarative::Yes);
+  if (shadowRoot) {
+    // https://html.spec.whatwg.org/#parsing-main-inhead:available-to-element-internals
+    shadowRoot->SetAvailableToElementInternals();
+  }
   return shadowRoot;
 }
 

diff --git a/...m/tests/shadow-dom/declarative/declarative-shadow-dom-available-to-element-internals.html b/...m/tests/shadow-dom/declarative/declarative-shadow-dom-available-to-element-internals.html
@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Declarative Shadow DOM</title>
+<link rel="author" href="mailto:[email protected]">
+<link rel="help" href="https://html.spec.whatwg.org/#parsing-main-inhead:available-to-element-internals">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<custom-element>
+    <template shadowrootmode="open">
+    </template>
+</custom-element>
+
+<script>
+    let internals;
+    customElements.define("custom-element", class extends HTMLElement {
+        constructor() {
+            super();
+            internals = this.attachInternals();
+        }
+    });
+
+    window.onload = () => {
+        test(() => {
+            assert_true(!!internals);
+            assert_true(!!internals.shadowRoot);
+            assert_equals(internals.shadowRoot, document.querySelector("custom-element").shadowRoot);
+        }, "Declarative Shadow DOM: shadow root should be available to element internals");
+    };
+</script>