[General] Don't use context from useHandler

packages/react-native-gesture-handler/src/handlers/gestures/reanimatedWrapper.ts

@@ -77,6 +77,7 @@ let Reanimated:
       runOnUI<A extends any[], R>(
         fn: (...args: A) => R
       ): (...args: Parameters<typeof fn>) => void;
+      makeMutable<T>(value: T): { value: T };
     }
   | undefined;
 

packages/react-native-gesture-handler/src/v3/hooks/callbacks/eventHandler.ts

@@ -3,7 +3,6 @@ import { CALLBACK_TYPE } from '../../../handlers/gestures/gesture';
 import type { ReanimatedContext } from '../../../handlers/gestures/reanimatedWrapper';
 import { State } from '../../../State';
 import { TouchEventType } from '../../../TouchEventType';
-import { tagMessage } from '../../../utils';
 import type {
   ChangeCalculatorType,
   GestureCallbacks,
@@ -93,16 +92,11 @@ export function handleUpdateEvent<
     : eventWithData;
 
   const event = flattenAndFilterEvent(eventWithChanges);
-
-  // This should never happen, but since we don't want to call hooks conditionally, we have to mark
-  // context as possibly undefined to make TypeScript happy.
-  if (!context) {
-    throw new Error(tagMessage('Event handler context is not defined'));
-  }
-
   runCallback(CALLBACK_TYPE.UPDATE, handlers, event);
 
-  context.lastUpdateEvent = eventWithData;
+  if (context) {
+    context.lastUpdateEvent = eventWithData;
+  }
 }
 
 export function handleTouchEvent<

packages/react-native-gesture-handler/src/v3/hooks/callbacks/useReanimatedEventHandler.ts

@@ -1,6 +1,9 @@
 import { useEffect, useMemo, useRef } from 'react';
 
-import type { ReanimatedHandler } from '../../../handlers/gestures/reanimatedWrapper';
+import type {
+  ReanimatedContext,
+  ReanimatedHandler,
+} from '../../../handlers/gestures/reanimatedWrapper';
 import { Reanimated } from '../../../handlers/gestures/reanimatedWrapper';
 import type {
   ChangeCalculatorType,
@@ -21,6 +24,16 @@ const workletNOOP = () => {
   // no-op
 };
 
+const lastUpdateEventMap = Reanimated?.makeMutable(
+  new Map<number, ReanimatedContext<unknown>>()
+);
+
+function deleteHandlerEventEntry(handlerTag: number) {
+  'worklet';
+  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+  lastUpdateEventMap!.value.delete(handlerTag);
+}
+
 export function useReanimatedEventHandler<
   THandlerData,
   TExtendedHandlerData extends THandlerData,
@@ -53,13 +66,21 @@ export function useReanimatedEventHandler<
     >
   ) => {
     'worklet';
+    // If we're on Reanimated path, lastUpdateEventMap should always be defined
+    // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+    let context = lastUpdateEventMap!.value.get(event.handlerTag);
+    if (context === undefined) {
+      context = { lastUpdateEvent: undefined };
+      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+      lastUpdateEventMap!.value.set(event.handlerTag, context);
+    }
+
     eventHandler(
       handlerTag,
       event,
       workletizedHandlers,
       changeEventCalculator,
-      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion, @typescript-eslint/no-non-null-asserted-optional-chain
-      reanimatedHandler?.context!,
+      context as ReanimatedContext<TExtendedHandlerData>,
       false,
       fillInDefaultValues
     );
@@ -77,6 +98,10 @@ export function useReanimatedEventHandler<
   // ref from what was actually committed.
   useEffect(() => {
     prevHandlerTagRef.current = handlerTag;
+
+    return () => {
+      Reanimated?.runOnUI?.(deleteHandlerEventEntry)(handlerTag);
+    };
   }, [handlerTag]);
 
   const reanimatedEvent = Reanimated?.useEvent(