fix: gesture not activating due to outdated handler tag

[hannojg]

Description

This fixes an issue where the manual activation of a handler wouldn't work.
I unfortunately didn't had time to make a full reproduction. The scenario roughly looks like this:

const gesture = useMemo(() -> Gesture.Pan() // Note happens also without useMemo
	.manualActivation(true)
	.onTouchesMove((event, manager) => {
			// Some criteria to met:
			manager.activate()
	})
	.onUpdate(() => {
		// Wouldn't get called on a remount
	})

return <GestureDetector gesture={gesture}> // ...

This is being used in a component on a screen. When we navigate from the screen the component gets unmounted and I can see that his logic is being triggered:

react-native-gesture-handler/packages/react-native-gesture-handler/src/handlers/gestures/GestureDetector/index.tsx

Lines 152 to 168 in 1e1f4e0

	useLayoutEffect(() => {
	const viewTag = findNodeHandle(state.viewRef) as number;
	preparedGesture.isMounted = true;
	attachHandlers({
	preparedGesture,
	gestureConfig,
	gesturesToAttach,
	webEventHandlersRef,
	viewTag,
	});
	return () => {
	preparedGesture.isMounted = false;
	dropHandlers(preparedGesture);
	};
	}, []);

attachHandler 1
dropHandler 1

I think the screen might get frozen instead of unmounted, but not entirely sure, but the cleanup function gets called and the handler gets dropped.
Now, when reopening the screen the handlers will reattach, but have a different handler tag now.

attachHandler 1
dropHandler 1
attachHandler 2 

When I now run the gesture I can see that the manager still has the previous handler tag, and thus on the native side it can't find the handler to activate. Its calling setGestureHandlerState(1 /* previous id */) here (when I call manager.activate):

react-native-gesture-handler/packages/react-native-gesture-handler/android/src/main/java/com/swmansion/gesturehandler/react/RNGestureHandlerModule.kt

Line 108 in 1e1f4e0

registry.getHandler(handlerTag)?.let { handler ->

I found that attaching the handler tag to the GestureStateMangaer and recreating it if it has changed fixes the issue.
If you need a full reproduction to proceed with this change I can understand, just let me know then I can try to find time to create one 👍

Test plan

Well, shamefully I didn't create a reproduction so I guess the test plan is "trust me bro" 😅 not the best I know - sorry.

[hannojg]

note: we only started observing this change after switching to new arch

[m-bert]

Hi @hannojg! Thanks for spotting this issue and submitting a PR! It would be great if you could prepare a small reproduction 😅
Also, could you mark handlerTag inside manager as internal?

[m-bert]

I can see that CI fails, could you also update gestureStateManager.web.ts file?