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

---

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[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.