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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /custom-elements/append-children-to-new-parent-cycle.html - WPT Dashboard Interop Dashboard
<!doctype html>
<html>
<head>
<title>
Custom Elements: adoption agency must not create a cyclic DOM when a
customized built-in reaction reparents the clone
</title>
<meta
name="assert"
content="The adoption agency AppendChildrenToNewParent step must not append into a node that has become its own descendant via a custom element reaction"
/>
<link rel="author" href="wpt@keithcirkel.co.uk" />
<link
rel="help"
/>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
</head>
<body>
<div id="log"></div>
<script>
const srcdoc = `<!doctype html>
<script>
class XBold extends HTMLElement {
static get observedAttributes() { return ["x"]; }
attributeChangedCallback() {
const marker = document.getElementById("marker");
if (!marker || window.moved) return;
window.moved = true;
marker.appendChild(this);
}
}
customElements.define("x-bold", XBold, {extends: "b"});
<\/script>
<b is="x-bold" x="1"><p id="marker"></b>`;
promise_test((t) => {
const iframe = document.createElement("iframe");
t.add_cleanup(() => iframe.remove());
const loaded = new Promise((resolve) => {
iframe.onload = resolve;
});
iframe.srcdoc = srcdoc;
document.body.appendChild(iframe);
return loaded.then(() => {
const doc = iframe.contentDocument;
const root = doc.documentElement;
for (const node of doc.querySelectorAll("*")) {
let depth = 0;
for (let a = node; a; a = a.parentNode) {
assert_less_than(
depth++,
100000,
"DOM ancestor chain must be finite (no cycle)",
);
if (a === root) break;
}
}
});
}, "Adoption agency reparenting a customized built-in clone must not create a cyclic DOM");
</script>
</body>
</html>