From d67e0c49067f3fd3cb19a02e88479eb00ff2f7ec Mon Sep 17 00:00:00 2001
From: Mason Freed <masonf@chromium.org>
Date: Wed, 14 Feb 2024 15:13:37 -0800
Subject: [PATCH] Only check for matching mode in attachShadow

Per the new-new consensus, attachShadow will only verify that
the existing declarative shadow root's `mode` matches the newly
requested `mode`:

https://github.com/whatwg/html/issues/10107#issuecomment-1937077298

Bug: 41483062
Change-Id: Ie3bac4ec297c0b85c40b45495e9c823dd47cb49e
---
 ...arative-shadow-dom-repeats.tentative.html} | 52 +++++++++++--------
 1 file changed, 31 insertions(+), 21 deletions(-)
 rename shadow-dom/declarative/{declarative-shadow-dom-repeats.html => declarative-shadow-dom-repeats.tentative.html} (55%)

diff --git a/shadow-dom/declarative/declarative-shadow-dom-repeats.html b/shadow-dom/declarative/declarative-shadow-dom-repeats.tentative.html
similarity index 55%
rename from shadow-dom/declarative/declarative-shadow-dom-repeats.html
rename to shadow-dom/declarative/declarative-shadow-dom-repeats.tentative.html
index 69f5c0f077afbc6..5a6ca341470059e 100644
--- a/shadow-dom/declarative/declarative-shadow-dom-repeats.html
+++ b/shadow-dom/declarative/declarative-shadow-dom-repeats.tentative.html
@@ -46,33 +46,43 @@
   assert_equals(shadow,initialShadow,'Same shadow should be returned');
   assert_equals(shadow.textContent,'','Shadow should be empty');
 },'Calling attachShadow() on declarative shadow root must match type');
-</script>
 
-<div id=open2>
-  <template shadowrootmode=open shadowrootdelegatesfocus shadowrootclonable>
-    Open, delegates focus (not the default), clonable (not the default)
-    named slot assignment (the default)
-  </template>
-</div>
+function getDeclarativeHost(t) {
+  const wrapper = document.createElement('div');
+  wrapper.setHTMLUnsafe(`<div>
+      <template shadowrootmode=open shadowrootdelegatesfocus shadowrootclonable serializable>
+        Open, delegates focus (not the default), clonable (not the default)
+        serializable (not the default), named slot assignment (the default)
+      </template>
+    </div>`);
+  t.add_cleanup(() => wrapper.remove());
+  document.body.appendChild(wrapper);
+  return wrapper.querySelector('div');
+}
 
-<script>
 test((t) => {
+  // Changing the type should throw.
+  let host = getDeclarativeHost(t);
+  assert_true(!!host.shadowRoot);
   assert_throws_dom("NotSupportedError",() => {
-    open2.attachShadow({mode: "closed", delegatesFocus: true, slotAssignment: "named", clonable: true});
+    host.attachShadow({mode: "closed"});
   },'Mismatched shadow root type should throw');
   assert_throws_dom("NotSupportedError",() => {
-    open2.attachShadow({mode: "open", delegatesFocus: false, slotAssignment: "named", clonable: true});
-  },'Mismatched shadow root delegatesFocus should throw');
-  assert_throws_dom("NotSupportedError",() => {
-    open2.attachShadow({mode: "open", delegatesFocus: true, slotAssignment: "manual", clonable: true});
-  },'Mismatched shadow root slotAssignment should throw');
-  assert_throws_dom("NotSupportedError",() => {
-    open2.attachShadow({mode: "open", delegatesFocus: true, slotAssignment: "named", clonable: false});
-  },'Mismatched shadow root clonable should throw');
+    host.attachShadow({mode: "closed", delegatesFocus: true, slotAssignment: "named", clonable: true, serializable: true});
+  },'Mismatched shadow root type should throw (explicit args)');
 
-  const initialShadow = open2.shadowRoot;
-  const shadow = open2.attachShadow({mode: "open", delegatesFocus: true, slotAssignment: "named", clonable: true}); // Shouldn't throw
-  assert_equals(shadow,initialShadow,'Same shadow should be returned');
-  assert_equals(shadow.textContent,'','Shadow should be empty');
+  // Changing other things should not throw, and should not change the shadow root's settings
+  const initialShadow = host.shadowRoot;
+  assert_equals(initialShadow.delegatesFocus,true);
+  assert_equals(initialShadow.slotAssignment,"named");
+  assert_true(initialShadow.clonable);
+  assert_true(initialShadow.serializable);
+  let newShadow = host.attachShadow({mode: "open", delegatesFocus: false, slotAssignment: "manual", clonable: false, serializable: false});
+  assert_equals(newShadow,initialShadow,'Same shadow should be returned');
+  assert_equals(newShadow.textContent,'','Shadow should be empty');
+  assert_equals(newShadow.delegatesFocus,true);
+  assert_equals(newShadow.slotAssignment,"named");
+  assert_true(newShadow.clonable);
+  assert_true(newShadow.serializable);
 },'Calling attachShadow() on declarative shadow root must match all parameters');
 </script>