fix(html): create wrappers for empty html innerHTML

moli-renderer-v8/src/document_runtime/document_write.rs

@@ -763,7 +763,14 @@ impl DocumentRuntime {
             .node(target)
             .map(|node| node.child_ids(self.dom_host().dom()).collect::<Vec<_>>())
             .unwrap_or_default();
-        if html.is_empty() && existing_children.is_empty() {
+        let empty_html_context_creates_document_wrappers = self
+            .dom_host()
+            .node(context)
+            .is_some_and(|node| node.is_html_element_named("html"));
+        if html.is_empty()
+            && existing_children.is_empty()
+            && !empty_html_context_creates_document_wrappers
+        {
             return false;
         }
         let Some(fragment) = self.build_fragment_from_html(

moli-renderer-v8/src/script_vm/tests/dom_elements/custom_elements.rs

@@ -7663,6 +7663,27 @@ fn document_element_inner_html_fragment_preserves_html_context_wrappers() {
     assert_eq!(result, "HEAD|BODY");
 }
 
+#[test]
+fn empty_detached_html_inner_html_creates_head_and_body() {
+    let mut vm = new_storage_test_vm("https://example.com/");
+
+    let result = vm
+        .eval(
+            r#"
+            (() => {
+              const html = document.createElement("html");
+              html.innerHTML = "";
+              return Array.from(html.childNodes)
+                .map(node => node.nodeName)
+                .join("|");
+            })()
+            "#,
+        )
+        .expect("empty detached HTML innerHTML probe should evaluate");
+
+    assert_eq!(result, "HEAD|BODY");
+}
+
 #[test]
 fn child_window_text_replacement_setters_dispatch_disconnected_callbacks() {
     let mut vm = new_storage_test_vm("https://example.com/");