From 80b0fbba1f9e3a8ce9a89aa88ae3efd4a1f60271 Mon Sep 17 00:00:00 2001
From: Kristiyan Kostadinov <crisbeto@abv.bg>
Date: Fri, 26 Dec 2025 10:14:21 +0200
Subject: [PATCH] fix(core): avoid leaking view data in animations

The animations code currently tracks which views have running leave animations by adding them to a `Set`. This can leak memory if we don't clean something up on time.

These changes switch to tracking the views by their ID which doesn't risk retaining the view.

Fixes #66255.
---
 packages/core/src/animation/longest_animation.ts       | 3 ++-
 packages/core/src/render3/instructions/animation.ts    | 6 +++---
 packages/core/src/render3/instructions/control_flow.ts | 5 +++--
 packages/core/src/render3/node_manipulation.ts         | 7 ++++---
 4 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/packages/core/src/animation/longest_animation.ts b/packages/core/src/animation/longest_animation.ts
index 46ced7b4f38..2ec1a520528 100644
--- a/packages/core/src/animation/longest_animation.ts
+++ b/packages/core/src/animation/longest_animation.ts
@@ -147,4 +147,5 @@ function determineLongestAnimationFromElementAnimations(
   }
 }
 
-export const allLeavingAnimations = new Set<LView>();
+/** Tracks the IDs of LViews with leaving animations. */
+export const allLeavingAnimations = new Set<number>();
diff --git a/packages/core/src/render3/instructions/animation.ts b/packages/core/src/render3/instructions/animation.ts
index ea8f70bcb6c..a85677095ca 100644
--- a/packages/core/src/render3/instructions/animation.ts
+++ b/packages/core/src/render3/instructions/animation.ts
@@ -13,7 +13,7 @@ import {
   MAX_ANIMATION_TIMEOUT,
 } from '../../animation/interfaces';
 import {getLView, getCurrentTNode} from '../state';
-import {RENDERER, INJECTOR, CONTEXT, LView} from '../interfaces/view';
+import {RENDERER, INJECTOR, CONTEXT, LView, ID} from '../interfaces/view';
 import {getNativeByTNode} from '../util/view_utils';
 import {performanceMarkFeature} from '../../util/performance';
 import {Renderer} from '../interfaces/renderer';
@@ -277,7 +277,7 @@ function runLeaveAnimations(
 
   const renderer = lView[RENDERER];
   const ngZone = lView[INJECTOR].get(NgZone);
-  allLeavingAnimations.add(lView);
+  allLeavingAnimations.add(lView[ID]);
   (getLViewLeaveAnimations(lView).get(tNode.index)!.resolvers ??= []).push(resolve);
 
   const activeClasses = getClassListFromValue(value);
@@ -389,7 +389,7 @@ export function ɵɵanimateLeaveListener(value: AnimationFunction): typeof ɵɵa
   const tNode = getCurrentTNode()!;
   cancelLeavingNodes(tNode, lView);
 
-  allLeavingAnimations.add(lView);
+  allLeavingAnimations.add(lView[ID]);
 
   addAnimationToLView(getLViewLeaveAnimations(lView), tNode, () =>
     runLeaveAnimationFunction(lView, tNode, value),
diff --git a/packages/core/src/render3/instructions/control_flow.ts b/packages/core/src/render3/instructions/control_flow.ts
index c38dec3ab8f..77339586aa1 100644
--- a/packages/core/src/render3/instructions/control_flow.ts
+++ b/packages/core/src/render3/instructions/control_flow.ts
@@ -28,6 +28,7 @@ import {
   DECLARATION_COMPONENT_VIEW,
   HEADER_OFFSET,
   HYDRATION,
+  ID,
   INJECTOR,
   LView,
   TVIEW,
@@ -578,7 +579,7 @@ function clearDetachAnimationList(lContainer: LContainer, index: number): void {
   if (lContainer.length <= CONTAINER_HEADER_OFFSET) return;
 
   const indexInContainer = CONTAINER_HEADER_OFFSET + index;
-  const viewToDetach = lContainer[indexInContainer];
+  const viewToDetach = lContainer[indexInContainer] as LView;
   const animations = viewToDetach
     ? (viewToDetach[ANIMATIONS] as AnimationLViewData | undefined)
     : undefined;
@@ -590,7 +591,7 @@ function clearDetachAnimationList(lContainer: LContainer, index: number): void {
   ) {
     const injector = viewToDetach[INJECTOR];
     removeFromAnimationQueue(injector, animations);
-    allLeavingAnimations.delete(viewToDetach);
+    allLeavingAnimations.delete(viewToDetach[ID]);
     animations.detachedLeaveAnimationFns = undefined;
   }
 }
diff --git a/packages/core/src/render3/node_manipulation.ts b/packages/core/src/render3/node_manipulation.ts
index 3212d7aabce..1e6f59afae1 100644
--- a/packages/core/src/render3/node_manipulation.ts
+++ b/packages/core/src/render3/node_manipulation.ts
@@ -76,6 +76,7 @@ import {
   TView,
   TViewType,
   INJECTOR,
+  ID,
 } from './interfaces/view';
 import {assertTNodeType} from './node_assert';
 import {profiler} from './profiler';
@@ -387,7 +388,7 @@ function runLeaveAnimationsWithCallback(
   if (animations == null || animations.leave == undefined || !animations.leave.has(tNode.index))
     return callback(false);
 
-  if (lView) allLeavingAnimations.add(lView);
+  if (lView) allLeavingAnimations.add(lView[ID]);
 
   addToAnimationQueue(
     injector,
@@ -410,7 +411,7 @@ function runLeaveAnimationsWithCallback(
         animations.running = Promise.allSettled(runningAnimations);
         runAfterLeaveAnimations(lView!, callback);
       } else {
-        if (lView) allLeavingAnimations.delete(lView);
+        if (lView) allLeavingAnimations.delete(lView[ID]);
         callback(false);
       }
     },
@@ -423,7 +424,7 @@ function runAfterLeaveAnimations(lView: LView, callback: Function) {
   if (runningAnimations) {
     runningAnimations.then(() => {
       lView[ANIMATIONS]!.running = undefined;
-      allLeavingAnimations.delete(lView);
+      allLeavingAnimations.delete(lView[ID]);
       callback(true);
     });
     return;