requestCurrentTransition inside ReactFabric-dev.js can throw unhandled exceptions

[chrismiddle10]

Description

Thus far I have been able to track down the issue to this file and line of code: react-native/Libraries/Renderer/implementations/ReactFabric-dev.js

function requestCurrentTransition() {
    var transition = ReactCurrentBatchConfig$1.transition;

    if (transition !== null) {
        // Whenever a transition update is scheduled, register a callback on the
        // transition object so we can get the return value of the scope function.
>>> transition._callbacks.add(handleAsyncAction); <<< SOMETIMES CALLBACKS IS UNDEFINED
    }

    return transition;
}

I apologize that I do not have a reproducible example for you. Everything does seem to operate correctly if I simply wrap the offending line in an empty try-catch.

Steps to reproduce

n/a

React Native Version

0.76.2

Affected Platforms

Runtime - iOS

Output of npx react-native info

System:
  OS: macOS 14.2.1
  CPU: (10) arm64 Apple M1 Pro
  Memory: 102.55 MB / 16.00 GB
  Shell:
    version: "5.9"
    path: /bin/zsh
Binaries:
  Node:
    version: 18.19.0
    path: ~/.nvm/versions/node/v18.19.0/bin/node
  Yarn:
    version: 1.22.19
    path: /usr/local/bin/yarn
  npm:
    version: 10.2.3
    path: ~/.nvm/versions/node/v18.19.0/bin/npm
  Watchman: Not Found
Managers:
  CocoaPods:
    version: 1.12.0
    path: /Users/chris/.rbenv/shims/pod
SDKs:
  iOS SDK:
    Platforms:
      - DriverKit 23.4
      - iOS 17.4
      - macOS 14.4
      - tvOS 17.4
      - visionOS 1.1
      - watchOS 10.4
  Android SDK: Not Found
IDEs:
  Android Studio: 2024.2 AI-242.21829.142.2421.12409432
  Xcode:
    version: 15.3/15E204a
    path: /usr/bin/xcodebuild
Languages:
  Java:
    version: 17.0.12
    path: /usr/bin/javac
  Ruby:
    version: 2.7.5
    path: /Users/chris/.rbenv/shims/ruby
npmPackages:
  "@react-native-community/cli":
    installed: 15.0.1
    wanted: 15.0.1
  react:
    installed: 18.3.1
    wanted: 18.3.1
  react-native:
    installed: 0.76.2
    wanted: 0.76.2
  react-native-macos: Not Found
npmGlobalPackages:
  "*react-native*": Not Found
Android:
  hermesEnabled: true
  newArchEnabled: true
iOS:
  hermesEnabled: true
  newArchEnabled: true

Stacktrace or Logs

TypeError: Cannot read property 'add' of undefined
    at requestCurrentTransition (http://localhost:8081/index.bundle//&platform=ios&dev=true&lazy=true&minify=false&inlineSourceMap=false&modulesOnly=false&runModule=true&excludeSource=true&sourcePaths=url-server&app={BUNDLE_ID}:13106:36)
    at requestUpdateLane (http://localhost:8081/index.bundle//&platform=ios&dev=true&lazy=true&minify=false&inlineSourceMap=false&modulesOnly=false&runModule=true&excludeSource=true&sourcePaths=url-server&app={BUNDLE_ID}:15752:50)
    at dispatchSetState (http://localhost:8081/index.bundle//&platform=ios&dev=true&lazy=true&minify=false&inlineSourceMap=false&modulesOnly=false&runModule=true&excludeSource=true&sourcePaths=url-server&app={BUNDLE_ID}:9607:37)
    at anonymous (http://localhost:8081/index.bundle//&platform=ios&dev=true&lazy=true&minify=false&inlineSourceMap=false&modulesOnly=false&runModule=true&excludeSource=true&sourcePaths=url-server&app={BUNDLE_ID}:373831:17)
    at anonymous (http://localhost:8081/index.bundle//&platform=ios&dev=true&lazy=true&minify=false&inlineSourceMap=false&modulesOnly=false&runModule=true&excludeSource=true&sourcePaths=url-server&app={BUNDLE_ID}:373890:32)
    at startTransition (http://localhost:8081/index.bundle//&platform=ios&dev=true&lazy=true&minify=false&inlineSourceMap=false&modulesOnly=false&runModule=true&excludeSource=true&sourcePaths=url-server&app={BUNDLE_ID}:20591:16)
    at ?anon_0_ (http://localhost:8081/index.bundle//&platform=ios&dev=true&lazy=true&minify=false&inlineSourceMap=false&modulesOnly=false&runModule=true&excludeSource=true&sourcePaths=url-server&app={BUNDLE_ID}:373889:30)
    at next (native)
    at asyncGeneratorStep (http://localhost:8081/index.bundle//&platform=ios&dev=true&lazy=true&minify=false&inlineSourceMap=false&modulesOnly=false&runModule=true&excludeSource=true&sourcePaths=url-server&app={BUNDLE_ID}:23563:19)
    at _next (http://localhost:8081/index.bundle//&platform=ios&dev=true&lazy=true&minify=false&inlineSourceMap=false&modulesOnly=false&runModule=true&excludeSource=true&sourcePaths=url-server&app={BUNDLE_ID}:23577:29)
    at tryCallOne (address at InternalBytecode.js:1:1180)
    at anonymous (address at InternalBytecode.js:1:1874)

Reproducer

https://github.com/chrismiddle10/sorry-dont-have-one

Screenshots and Videos

No response

[jnleonard3]

This error was occurring for me when I was utilizing startTransition exported directly from react to wrap my Suspense transitions. When I started using the useTransition hook and the startTransition created from it, I no longer saw this.