MOB-M-9: REACT state update on an unmounted component

[obrien-j]

Performance Summary
When reviewing code in ../covid-shield- mobile/blob/add_device_capabilities/src/screens/home/HomeScreen.tsx#L58, the following suggestion was made

Unmounted component warning that points to a potential memory leak concern.

Analysis of the Issue
There is a warning when app is running in debug mode (at least in Android) that says there is a REACT state update on an unmounted component pointing to the Container component, indicating a memory leak.

Recommendation
Recommend to look into the useEffects() call to provide fix to address the memory leak issue.

[jeberhardt]

I looked into this quite a bit yesterday, and was unable to determine exactly which component was unmounted and trying to update the state.

To replicate on Android:

• Launch the app, running in debug mode (ie: not an app from TestFlight or the Play Store)
• Navigate through the app to go to a few screens
• Press the system back button until the app exits
• Press the icon to launch the app again
• A warning may appear at the bottom of the screen (YellowBox).

The warning doesn't happen every time, maybe only 50% of the time.

[henrytao-me]

@react-native-community/netinfo is the one causing the leak. Ref https://github.com/CovidShield/mobile/pull/139/files#diff-bb2a692e69dc457e8a5d5757bdaf9a3bR55

[jeberhardt]

Even with the updated netinfo package, this problem still persists. Same steps as above to replicate.

[henrytao-me]

Close as fixed.