Fix GestureDetector unresponsive after display:none toggle (New Arch)

[janicduplessis]

Description

On New Architecture, when a parent view has display: 'none' and siblings change while hidden, the native UIView backing a component may be recycled and replaced. The React view tag stays the same but the UIView instance changes, causing gesture recognizers to be lost.

This adds a reattachHandlersIfNeeded check in flushOperations that re-binds handlers whose native view has changed. The check is a fast no-op (pointer comparison) when views haven't been recycled.

Fixes #3937

Test plan

Tested with both v2 (Gesture.Tap()) and v3 (useTapGesture) APIs on iOS simulator (New Architecture).

Minimal repro to verify the fix:

import React, { useCallback, useState } from 'react';
import { Button, StyleSheet, Text, View } from 'react-native';
import { Gesture, GestureDetector } from 'react-native-gesture-handler';

export default function DisplayNone() {
  const [tapCountV2, setTapCountV2] = useState(0);

  const tapV2 = Gesture.Tap()
    .runOnJS(true)
    .onStart(() => {
      setTapCountV2((c) => c + 1);
    });

  const [visible, setVisible] = useState(true);
  const [randomViews, setRandomViews] = useState(100);

  const runTest = useCallback(() => {
    setVisible(false);
    setTimeout(() => {
      setRandomViews(Math.random() * 100);
      setTimeout(() => {
        setVisible(true);
      }, 500);
    }, 500);
  }, []);

  return (
    <View style={styles.container}>
      <Text
        style={[
          styles.status,
          { color: tapCountV2 > 0 ? 'green' : 'red', fontSize: 24 },
        ]}>
        v2 Tap count: {tapCountV2}
      </Text>
      <Button title="Run Test (Hide→Change→Show)" onPress={runTest} />
      <View
        style={[
          styles.wrapper,
          {
            display: visible ? 'flex' : 'none',
          },
        ]}>
        <View style={styles.row}>
          {Array.from({ length: randomViews }).map((_, i) => (
            <View key={i} style={styles.dot} />
          ))}
        </View>
        <View style={styles.boxRow}>
          <GestureDetector gesture={tapV2}>
            <View style={styles.blueBox}>
              <Text style={styles.blueBoxText}>v2</Text>
            </View>
          </GestureDetector>
        </View>
      </View>
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#ecf0f1',
    padding: 8,
  },
  status: {
    fontSize: 16,
    fontWeight: 'bold',
    marginBottom: 20,
    textAlign: 'center',
  },
  wrapper: {
    marginTop: 50,
    gap: 20,
    backgroundColor: 'yellow',
  },
  row: {
    flexDirection: 'row',
  },
  dot: {
    width: 2,
    height: 2,
    backgroundColor: 'black',
  },
  boxRow: {
    flexDirection: 'row',
    gap: 20,
  },
  blueBox: {
    height: 50,
    width: 50,
    backgroundColor: 'blue',
    justifyContent: 'center',
    alignItems: 'center',
  },
  blueBoxText: {
    color: 'white',
    fontWeight: 'bold',
  },
});

Steps:

1. Tap the box — count increments
2. Press "Hide → Change → Show" to trigger display:none + sibling change + show
3. Tap again — count should still increment (was broken before this fix)
4. Repeat multiple cycles to confirm reliability

[Copilot]

Pull request overview

Fixes GestureDetector becoming unresponsive on Fabric after a display: 'none' hide/show cycle by reattaching gesture handlers when Fabric recycles underlying UIView instances.

Changes:

• Track the React view tag (viewTag) each handler is bound to and clear it on unbind
• Add a reattach pass (reattachHandlersIfNeeded) executed after each UI operations flush
• Add a basic-example repro screen for the display:none recycling scenario

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
packages/react-native-gesture-handler/apple/RNGestureHandlerRegistry.m	Refactors registry implementation to support exposing handler collection
packages/react-native-gesture-handler/apple/RNGestureHandlerRegistry.h	Exposes registry handlers collection for reattach iteration
packages/react-native-gesture-handler/apple/RNGestureHandlerModule.mm	Ensures UI block runs to reattach handlers after flush
packages/react-native-gesture-handler/apple/RNGestureHandlerManager.mm	Adds helper for binding + reattach pass over registered handlers
packages/react-native-gesture-handler/apple/RNGestureHandlerManager.h	Exposes reattachHandlersIfNeeded on manager
packages/react-native-gesture-handler/apple/RNGestureHandler.mm	Stores viewTag when binding and clears it on unbind
packages/react-native-gesture-handler/apple/RNGestureHandler.h	Adds viewTag property to handler
apps/basic-example/src/DisplayNone.tsx	Adds a repro/testing screen for the Fabric display:none issue
apps/basic-example/src/App.tsx	Registers the new example screen in the example list

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

This enumerates _registry.handlers while calling maybeBindHandler, which in turn calls into registry attach logic (attachHandlerWithTag:...). If the registry mutates its handlers dictionary as part of (re)attach, this risks a “mutated while being enumerated” crash. Safer approach: iterate over a snapshot (e.g., _registry.handlers.allValues captured into an array before the loop, or iterate over a copied dictionary’s values).

[janicduplessis]

This is safe because attachHandlerWithTag:toView:withActionType:withHostDetector: in the registry only mutates existing entries (calls unbindFromView/bindToView on a handler that's already in the dictionary). It never adds or removes keys from _handlers, so the dictionary is not structurally mutated during enumeration.

[janicduplessis]

Using objectEnumerator here instead of allValues to avoid allocating a temporary array on every flush.

[j-piasecki]

The reproduction seems to work without the changes from the PR:

Simulator.Screen.Recording.-.iPhone.17.Pro.-.2026-02-09.at.11.09.49.mov

Or am I missing something?

[janicduplessis]

@j-piasecki Sorry I oversimplified the repro, I updated it and tested it works.

[j-piasecki]

Hey, sorry for the delay! This should be fixed for the hook-based API by #3967. Can I ask you to double-check that? If it already works in the V3 API, can you gate the logic in this PR so it doesn't run for V3?

You can use this method to check if the gesture is being used as part of the new API.