Onyx connection can be called twice for the same data

[hannojg]

There exists a "race condition" where an Onyx connection callback will be called twice for the same data. Potentially this can lead to unnecessary rerenders in the react applications.

The race condition happens when creating a connection and shortly after setting the data:

It once gets called here in .set:

react-native-onyx/lib/Onyx.ts

Lines 274 to 275 in c53826b

	// This approach prioritizes fast UI changes without waiting for data to be stored in device storage.
	const updatePromise = OnyxUtils.broadcastUpdate(key, valueWithoutNullValues, hasChanged);

and then here once the connection promise resolved:

react-native-onyx/lib/Onyx.ts

Line 175 in c53826b

OnyxUtils.get(mapping.key).then((val) => OnyxUtils.sendDataToConnection(mapping, val as OnyxValue<TKey>, mapping.key, true));

[hannojg]

I think I could build a failing unit test and fix the issue (cc @mountiny @marcaaron )

[mountiny]

@hannojg yes please, feel free to investigate a fix for this

[hannojg]

PR is up here:

• fix: connection could be called twice on set #570

[mountiny]

@hannojg are you able to create the onyx bump now with the checklist filled in? thanks!

[hannojg]

Hey, yes I could, but I think you mentioned me in some other issue and someone else is doing the bump, no?

[mountiny]

Yeah that was after i commented here, i think they can handle that for you

[hannojg]

My first PR caused a few test to fail in the newdot code. I addressed the problems in these PRs (would appreciate a review):

• fix: reset keys to initial state if they were set to null #573
• fix: Onyx.clear handle collections and regular keys with an underscore #574
• fix: free memory from internal cache when disconnecting #575

[mountiny]

@hannojg I believe these changes are now live in the App, thank you! Do you reckon we can close this issue out?

[hannojg]

Yes, thats fixed now!