Merge pull request #1710 from lightpanda-io/custom_element_clone

Support for clone custom elements that attach them self in their cons…

src/browser/tests/custom_elements/constructor.html

@@ -53,3 +53,22 @@
     testing.expectEqual('NO-CONSTRUCTOR-ELEMENT', el.tagName);
 }
 </script>
+
+<div id=clone_container></div>
+
+<script id=clone>
+    {
+        let calls = 0;
+        class MyCloneElementA extends HTMLElement {
+            constructor() {
+                super();
+                calls += 1;
+                $('#clone_container').appendChild(this);
+            }
+        }
+        customElements.define('my-clone_element_a', MyCloneElementA);
+        const original = document.createElement('my-clone_element_a');
+         $('#clone_container').cloneNode(true);
+        testing.expectEqual(2, calls);
+    }
+</script>

src/browser/webapi/Element.zig

@@ -1329,9 +1329,18 @@ pub fn clone(self: *Element, deep: bool, page: *Page) !*Node {
         var child_it = self.asNode().childrenIterator();
         while (child_it.next()) |child| {
             const cloned_child = try child.cloneNode(true, page);
+            if (cloned_child._parent != null) {
+                // This is almost always false, the only case where a cloned
+                // node would already have a parent is with a custom element
+                // that has a constructor (which is called during cloning) which
+                // inserts it somewhere. In that case, whatever parent was set
+                // in the constructor should not be changed.
+                continue;
+            }
+
             // We pass `true` to `child_already_connected` as a hacky optimization
-            // We _know_ this child isn't connected (Becasue the parent isn't connected)
+            // We _know_ this child isn't connected (Because the parent isn't connected)
-            // setting this to `true` skips all connection checks and just assumes t
+            // setting this to `true` skips all connection checks.
             try page.appendNode(node, cloned_child, .{ .child_already_connected = true });
         }
     }