[Bug] View not removed on return null in Observer after upgrading RN 0.82.1 → 0.83.0 #54940
Description
Description
On React Native 0.82.1, returning null from a MobX render would remove the previously rendered view.
After upgrading to React Native 0.83.0 (React 19.2) the view does not get removed as expected:
{() => {
switch (this.status) {
case 'loading':
return (
<ActivityIndicator style={{ width: 49, height: 49 }} size="small" color={colors.grey} />
);
case 'processing':
return (
);
}
return null;
}}
Steps to reproduce
1. Create a minimal RN app with 0.82.1
2. Render a conditional UI via MobX <Observer> that returns an element or null
3. Change state to cause render to return null
4. UI is correctly removed on 0.82.1
5. Upgrade to RN 0.83.0
6. Repeat steps: view is not removed when render returns null
import { Observer } from "mobx-react-lite";
import { ActivityIndicator, View } from "react-native";
class Store {
status = "idle"; // or 'loading' / 'processing'
}
const store = new Store();
// In component:
{() => {
switch (store.status) {
case "loading":
return ;
case "processing":
return ;
}
return null;
}}
React Native Version
react-native: 0.83.0 react: 19.2.0 mobx:6.15.0 mobx-react-lite: 4.1.1
Affected Platforms
Runtime - iOS, Runtime - Android
Output of npx @react-native-community/cli info
System:
OS: macOS 15.6.1
CPU: (10) arm64 Apple M1 Max
Memory: 256.20 MB / 32.00 GB
Shell:
version: "5.9"
path: /bin/zsh
Binaries:
Node:
version: 25.1.0
path: /usr/local/bin/node
Yarn:
version: 1.22.22
path: ~/.yarn/bin/yarn
npm:
version: 11.6.2
path: /opt/homebrew/bin/npm
Watchman:
version: 2025.04.07.00
path: /opt/homebrew/bin/watchman
Managers:
CocoaPods:
version: 1.16.2
path: /opt/homebrew/bin/pod
SDKs:
iOS SDK:
Platforms:
- DriverKit 25.2
- iOS 26.2
- macOS 26.2
- tvOS 26.2
- visionOS 26.2
- watchOS 26.2
Android SDK: Not Found
IDEs:
Android Studio: 2025.1 AI-251.26094.121.2512.13930704
Xcode:
version: 26.2/17C52
path: /usr/bin/xcodebuild
Languages:
Java:
version: 19.0.1
path: /usr/bin/javac
Ruby:
version: 3.4.2
path: /opt/homebrew/opt/ruby/bin/ruby
npmPackages:
"@react-native-community/cli":
installed: 20.0.0
wanted: 20.0.0
react:
installed: 19.2.0
wanted: 19.2.0
react-native:
installed: 0.83.0
wanted: 0.83.0
react-native-macos: Not Found
npmGlobalPackages:
"*react-native*": Not Found
Android:
hermesEnabled: true
newArchEnabled: true
iOS:
hermesEnabled: true
newArchEnabled: true
Stacktrace or Logs
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MANDATORY Reproducer
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Screenshots and Videos
No response