LayoutAnimationController [sometimes] leaks memory

[knappam]

Description

Android's onAnimationEnd callback is lossy and ocasionally just does not fire. However the LayoutAnimationController maintains a sparse array of animations (with Strong View refs) that is only cleaned when the onAnimationEnd callback is invoked. This results in a leak of Android View objects over time.

Steps to reproduce

1. Write an RN application that uses LayoutAnimations (alot)
2. Collect heap dumps and note the Views that should have been GCed are being held by the mkLayoutHanders field in LayoutAnimationController.java

React Native Version

0.78.0

Affected Platforms

Runtime - Android

Output of npx @react-native-community/cli info

System:
  OS: Linux 6.11 Ubuntu 24.04.2 LTS 24.04.2 LTS (Noble Numbat)
  CPU: (32) x64 AMD Ryzen 9 9950X 16-Core Processor
  Memory: 33.39 GB / 60.45 GB
  Shell:
    version: 5.2.21
    path: /bin/bash
Binaries:
  Node:
    version: 23.2.0
    path: ~/.nvm/versions/node/v23.2.0/bin/node
  Yarn:
    version: 1.22.22
    path: ~/.nvm/versions/node/v23.2.0/bin/yarn
  npm:
    version: 10.9.0
    path: ~/.nvm/versions/node/v23.2.0/bin/npm
  Watchman: Not Found
SDKs:
  Android SDK:
    API Levels:
      - "24"
      - "28"
      - "33"
      - "34"
      - "35"
    Build Tools:
      - 28.0.3
      - 30.0.3
      - 34.0.0
      - 35.0.0
    System Images:
      - android-35 | Google Play Intel x86_64 Atom
    Android NDK: Not Found
IDEs:
  Android Studio: Not Found
Languages:
  Java:
    version: 21.0.5
    path: /usr/bin/javac
  Ruby:
    version: 3.2.3
    path: /usr/bin/ruby
npmPackages:
  "@react-native-community/cli": Not Found
  react:
    installed: 18.2.0
    wanted: 19.0.0
  react-native: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: Not found
  newArchEnabled: Not found
iOS:
  hermesEnabled: Not found
  newArchEnabled: Not found

Stacktrace or Logs

Cannot share the heap dumps

Reproducer

n/a

Screenshots and Videos

[react-native-bot]

Warning

Missing reproducer: We could not detect a reproducible example in your issue report. Please provide either:

• If your bug is UI related: a Snack
• If your bug is build/upgrade related: a project using our Reproducer Template
• Otherwise send us a Pull Request with the RNTesterPlayground.js edited to reproduce your bug.

[devanshsaini11]

Hi @knappam can u please provide a repro so it can be validated quickly

[cipolleschi]

@cortinico possible fix in #49959