From 27a12acda1c6e14d1ad979f75531d4154aad52a3 Mon Sep 17 00:00:00 2001
From: Piers Wombwell <piersw@gmail.com>
Date: Sat, 4 Jul 2026 19:02:50 +0100
Subject: [PATCH] Restore deep cloning of clonable shadow root contents.

This restores the behaviour introduced by #1272.

After #1334, the shadow-root cloning step says to clone each child of the shadow root with `subtree` set to `subtree`. When the original call is `host.cloneNode(false)`, that causes each direct child of a clonable shadow root to be cloned shallowly.

That contradicts the behaviour agreed in #1249 / #1272 and the WPT `shadow-dom/shadow-root-clonable.html`, which expects a clonable shadow root to be cloned in its entirety even when the shadow host is shallow-cloned.
---
 dom.bs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dom.bs b/dom.bs
index bc2d42c6..590ac26d 100644
--- a/dom.bs
+++ b/dom.bs
@@ -4964,7 +4964,7 @@ and an optional <a for=/>document</a> <dfn export for="clone a node"><var>docume
     <p>For each <var>child</var> of <var>node</var>'s <a for=Element>shadow root</a>'s
     <a for=tree>children</a>, in <a>tree order</a>: <a>clone a node</a> given <var>child</var> with
     <a for="clone a node"><i>document</i></a> set to <var>document</var>,
-    <a for="clone a node"><i>subtree</i></a> set to <var>subtree</var>, and
+    <a for="clone a node"><i>subtree</i></a> set to true, and
     <a for="clone a node"><i>parent</i></a> set to <var>copy</var>'s <a for=Element>shadow root</a>.
 
     <p class="note">This intentionally does not pass the