LibWeb: Implement [SameObject] behavior for HTMLFormElement.elements

3 files changed, 11 insertions, 7 deletions

diff --git a/Userland/Libraries/LibWeb/HTML/HTMLFormElement.cpp b/Userland/Libraries/LibWeb/HTML/HTMLFormElement.cpp
index 647bec6413..fd58ef88af 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLFormElement.cpp
+++ b/Userland/Libraries/LibWeb/HTML/HTMLFormElement.cpp
@@ -33,6 +33,7 @@ HTMLFormElement::~HTMLFormElement() = default;
 void HTMLFormElement::visit_edges(Cell::Visitor& visitor)
 {
     Base::visit_edges(visitor);
+    visitor.visit(m_elements);
     for (auto& element : m_associated_elements)
         visitor.visit(element.ptr());
 }
@@ -185,11 +186,12 @@ static bool is_form_control(DOM::Element const& element)
 // https://html.spec.whatwg.org/multipage/forms.html#dom-form-elements
 JS::NonnullGCPtr<DOM::HTMLCollection> HTMLFormElement::elements() const
 {
-    // FIXME: This should return the same HTMLFormControlsCollection object every time,
-    //        but that would cause a reference cycle since HTMLCollection refs the root.
-    return DOM::HTMLCollection::create(const_cast<HTMLFormElement&>(*this), [](Element const& element) {
-        return is_form_control(element);
-    });
+    if (!m_elements) {
+        m_elements = DOM::HTMLCollection::create(const_cast<HTMLFormElement&>(*this), [](Element const& element) {
+            return is_form_control(element);
+        });
+    }
+    return *m_elements;
 }
 
 // https://html.spec.whatwg.org/multipage/forms.html#dom-form-length
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLFormElement.h b/Userland/Libraries/LibWeb/HTML/HTMLFormElement.h
index 69eea3e773..7e63706fd3 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLFormElement.h
+++ b/Userland/Libraries/LibWeb/HTML/HTMLFormElement.h
@@ -39,6 +39,8 @@ private:
     bool m_firing_submission_events { false };
 
     Vector<JS::GCPtr<HTMLElement>> m_associated_elements;
+
+    JS::GCPtr<DOM::HTMLCollection> mutable m_elements;
 };
 
 }
diff --git a/Userland/Libraries/LibWeb/HTML/HTMLFormElement.idl b/Userland/Libraries/LibWeb/HTML/HTMLFormElement.idl
index 9be32481e1..d282712987 100644
--- a/Userland/Libraries/LibWeb/HTML/HTMLFormElement.idl
+++ b/Userland/Libraries/LibWeb/HTML/HTMLFormElement.idl
@@ -12,8 +12,8 @@ interface HTMLFormElement : HTMLElement {
 
     undefined submit();
 
-    // FIXME: Should be [SameObject] and a HTMLFormControlsCollection
-    readonly attribute HTMLCollection elements;
+    // FIXME: Should be a HTMLFormControlsCollection
+    [SameObject] readonly attribute HTMLCollection elements;
 
     readonly attribute unsigned long length;