fix(forms): resolve live named properties without repeated scans

moli-dom/src/native/host/document.rs

@@ -810,6 +810,32 @@ impl DomHost {
             })
     }
 
+    /// Whether any current element can match this legacy named-property key.
+    ///
+    /// This is deliberately independent of connectivity and document/tree scope:
+    /// callers may use a miss to avoid a traversal, but must still validate the
+    /// owner and scope on a hit. Reuse the incrementally maintained named indexes
+    /// rather than caching misses (custom-element upgrades can change eligibility
+    /// without changing an element's id or name).
+    pub fn has_element_with_named_item_key(&self, key: &str) -> bool {
+        if key.is_empty() {
+            return false;
+        }
+        self.ensure_id_index();
+        self.ensure_name_index();
+        let matches = |index: &NamedElementIndex| {
+            index.handles_by_value.get(key).is_some_and(|handles| {
+                handles.iter().any(|handle| {
+                    self.node(*handle)
+                        .and_then(Node::as_element)
+                        .is_some_and(|element| element.matches_named_item_key(key))
+                })
+            })
+        };
+        self.id_index.borrow().as_ref().is_some_and(matches)
+            || self.name_index.borrow().as_ref().is_some_and(matches)
+    }
+
     pub fn element_handles_by_id_or_name_matching(
         &self,
         key: &str,

moli-dom/src/native/host/query_index.rs

@@ -518,6 +518,29 @@ mod tests {
         ))
     }
 
+    #[test]
+    fn global_named_item_candidate_check_tracks_live_attributes_in_detached_trees() {
+        let mut host = test_host();
+        assert!(!host.has_element_with_named_item_key("late"));
+        assert!(!host.has_element_with_named_item_key(""));
+        let input = host.create_element("input");
+        assert!(host.set_attribute(input, "name", "late"));
+        assert!(host.has_element_with_named_item_key("late"));
+        assert!(host.set_attribute(input, "name", "renamed"));
+        assert!(!host.has_element_with_named_item_key("late"));
+        assert!(host.has_element_with_named_item_key("renamed"));
+        assert!(host.set_attribute(input, "id", "renamed"));
+        assert!(host.remove_attribute(input, "name"));
+        assert!(host.has_element_with_named_item_key("renamed"));
+        let root = host.create_element("div");
+        assert!(host.append_child(root, input));
+        assert!(host.has_element_with_named_item_key("renamed"));
+        assert!(host.remove_attribute(input, "id"));
+        assert!(!host.has_element_with_named_item_key("renamed"));
+        assert!(host.set_attribute(input, "name", ""));
+        assert!(!host.has_element_with_named_item_key(""));
+    }
+
     #[test]
     fn cached_tag_name_collection_reuses_query_until_mutation() {
         let mut host = test_host();

moli-renderer-v8/src/native_bridge/document/detached_objects/builders/elements.rs

@@ -487,9 +487,16 @@ pub(in crate::native_bridge::document) fn build_detached_element_object<'s>(
     let mut object = if let Some(proto) =
         element_interface_prototype(scope, owner_document, prototype_name, html_interface_like)
     {
-        DetachedElementObjectDeclaration::new(proto, to_string_tag)
-            .bind(scope)
-            .ok()?
+        let declaration = DetachedElementObjectDeclaration::new(proto, to_string_tag);
+        if html_interface_like && local_name == "form" {
+            let template = v8::ObjectTemplate::new(scope);
+            crate::native_bridge::element::install_form_property_handlers(template);
+            let object = template.new_instance(scope)?;
+            declaration.bind_into(scope, object).ok()?;
+            object
+        } else {
+            declaration.bind(scope).ok()?
+        }
     } else {
         new_detached_object_with_prototype(scope, "__detachedElementPrototype", to_string_tag)?
     };

moli-renderer-v8/src/native_bridge/element.rs

@@ -34,6 +34,32 @@ mod event_handlers;
 mod events;
 mod focus;
 mod forms;
+
+#[cfg(test)]
+std::thread_local! {
+    static FORM_LOOKUP_WORK: std::cell::Cell<(u64, u64)> = const { std::cell::Cell::new((0, 0)) };
+}
+
+#[cfg(test)]
+pub(crate) fn take_form_lookup_work_for_test() -> (u64, u64) {
+    FORM_LOOKUP_WORK.with(|work| work.replace((0, 0)))
+}
+
+#[cfg(test)]
+fn record_form_lookup_traversal_for_test() {
+    FORM_LOOKUP_WORK.with(|work| {
+        let (traversals, enumerations) = work.get();
+        work.set((traversals + 1, enumerations));
+    });
+}
+
+#[cfg(test)]
+fn record_form_lookup_enumeration_for_test() {
+    FORM_LOOKUP_WORK.with(|work| {
+        let (traversals, enumerations) = work.get();
+        work.set((traversals, enumerations + 1));
+    });
+}
 mod geometry;
 mod global_attributes;
 mod html_elements;
@@ -645,7 +671,8 @@ use stylesheets::{
     style_blocking_setter_function, style_disabled_getter_function, style_disabled_setter_function,
 };
 pub(super) use template_install::{
-    install_specialized_instance_properties, install_specialized_template,
+    install_form_property_handlers, install_specialized_instance_properties,
+    install_specialized_template,
 };
 pub(super) use tree_mutation::{
     node_insert_adjacent_element_callback, node_insert_adjacent_html_callback,

moli-renderer-v8/src/native_bridge/element/forms.rs

@@ -18,7 +18,7 @@ use super::super::{
         current_or_live_delegate_node_arg_handle, insert_before_in_reaction_scope,
         insert_before_to_current_reaction_queue, node_or_foreign_arg_handle,
         node_or_foreign_arg_handle_allow_detached, node_runtime_and_handle_from_args,
-        node_runtime_and_handle_from_args_or_detached, node_runtime_and_handle_from_object,
+        node_runtime_and_handle_from_args_or_detached,
         node_runtime_and_handle_from_object_or_detached, remove_child_in_reaction_scope,
         remove_child_to_current_reaction_queue, set_text_content_in_reaction_scope,
         set_wrapped_node_or_null,