From c8b574e9b4f7d771277507520592b2084fa42ce9 Mon Sep 17 00:00:00 2001
From: Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
Date: Sat, 19 Jul 2025 03:34:13 +0200
Subject: [PATCH] LibWeb: Remove animations from timeline in
 `Element::removed_from()`

`AnimationTimeline` visits pointers of all registered animations, so if
element is removed from DOM tree but its animations remain registered in
timeline, then `Animation` and owner `Element` will be kept alive until
`AnimationTimeline` is destroyed.
---
 Libraries/LibWeb/Animations/Animatable.cpp | 9 +++++++++
 Libraries/LibWeb/Animations/Animatable.h   | 2 ++
 Libraries/LibWeb/DOM/Element.cpp           | 1 +
 3 files changed, 12 insertions(+)

diff --git a/Libraries/LibWeb/Animations/Animatable.cpp b/Libraries/LibWeb/Animations/Animatable.cpp
index 8ed2c17d1ca..c0371dd1b76 100644
--- a/Libraries/LibWeb/Animations/Animatable.cpp
+++ b/Libraries/LibWeb/Animations/Animatable.cpp
@@ -235,6 +235,15 @@ void Animatable::clear_transitions(Optional<CSS::PseudoElement> pseudo_element)
     transition.transition_attributes.clear();
 }
 
+void Animatable::remove_animations_from_timeline()
+{
+    // This is needed to avoid leaking Animation objects
+    auto& impl = ensure_impl();
+    for (auto animation : impl.associated_animations) {
+        animation->set_timeline({});
+    }
+}
+
 void Animatable::visit_edges(JS::Cell::Visitor& visitor)
 {
     auto& impl = ensure_impl();
diff --git a/Libraries/LibWeb/Animations/Animatable.h b/Libraries/LibWeb/Animations/Animatable.h
index 09afeb8f4d7..1efb3446d4c 100644
--- a/Libraries/LibWeb/Animations/Animatable.h
+++ b/Libraries/LibWeb/Animations/Animatable.h
@@ -67,6 +67,8 @@ public:
     GC::Ptr<CSS::CSSTransition> property_transition(Optional<CSS::PseudoElement>, CSS::PropertyID) const;
     void clear_transitions(Optional<CSS::PseudoElement>);
 
+    void remove_animations_from_timeline();
+
 protected:
     void visit_edges(JS::Cell::Visitor&);
 
diff --git a/Libraries/LibWeb/DOM/Element.cpp b/Libraries/LibWeb/DOM/Element.cpp
index c375df3be16..9557d992a28 100644
--- a/Libraries/LibWeb/DOM/Element.cpp
+++ b/Libraries/LibWeb/DOM/Element.cpp
@@ -1356,6 +1356,7 @@ void Element::removed_from(Node* old_parent, Node& old_root)
     }
 
     play_or_cancel_animations_after_display_property_change();
+    remove_animations_from_timeline();
 }
 
 void Element::moved_from(GC::Ptr<Node> old_parent)