fix(iOS): white flash on tab change when using native stack (#2188)

## Description

This PR gets rid of undesired white flashes during
`maybeAddToParentAndUpdateContainer`. The white flash was present on
paper architecture when `unmountOnBlur` option was set to true on parent
bottomStackNavigator (see repro).

The affected logic was previously introduced or changed by following
PRs:
- #600
- #613
- #643


The removed `_hasLayout` was initially added by
#600 in
order to resolve an issue:
#432.
However the logic was later changed by
#613 in
order to fix another issue and the added `_hasLayout` may not fix
anything eventually, as stated by [this
comment](#432 (comment)).

Fixes #1645.

## Changes

- removed `_hasLayout` variable
- added repros

## Screenshots / GIFs

### Before


https://github.com/software-mansion/react-native-screens/assets/91994767/226a32d7-728b-48dd-b21a-6a1e4195add2

### After


https://github.com/software-mansion/react-native-screens/assets/91994767/32febcf1-d159-4a9d-ae3a-373042732a6d

## Test code and steps to reproduce

- added `Test1645.js` repro to test examples
- added `Test432.tsx` repro to test examples

## Checklist

- [x] Included code example that can be used to test this change
- [x] Ensured that CI passes

---------

Co-authored-by: Kacper Kafara <kacper.kafara@swmansion.com>

apps/test-examples/App.js

@@ -8,6 +8,7 @@ import Test111 from './src/Test111';
 import Test263 from './src/Test263';
 import Test349 from './src/Test349';
 import Test364 from './src/Test364';
+import Test432 from './src/Test432';
 import Test528 from './src/Test528';
 import Test550 from './src/Test550';
 import Test556 from './src/Test556';
@@ -84,6 +85,7 @@ import Test1473 from './src/Test1473';
 import Test1476 from './src/Test1476';
 import Test1509 from './src/Test1509';
 import Test1539 from './src/Test1539';
+import Test1645 from './src/Test1645';
 import Test1646 from './src/Test1646';
 import Test1649 from './src/Test1649';
 import Test1671 from './src/Test1671';

apps/test-examples/src/Test1645.js

@@ -0,0 +1,98 @@
+/* eslint-disable react-native/no-inline-styles */
+
+import React, {useEffect, useState} from 'react';
+import {Text, View} from 'react-native';
+
+import {createBottomTabNavigator} from '@react-navigation/bottom-tabs';
+import {createNativeStackNavigator} from '@react-navigation/native-stack';
+import {createStackNavigator} from '@react-navigation/stack';
+import {NavigationContainer} from '@react-navigation/native';
+
+const TestBottomTabBar = createBottomTabNavigator();
+const TestNativeStack1 = createNativeStackNavigator();
+const TestNativeStack2 = createNativeStackNavigator();
+
+const TestScreen1 = () => {
+  const [t, setT] = useState(110);
+
+  useEffect(() => {
+    const interval = setInterval(() => {
+      setT(lastT => lastT + 1);
+    }, 100);
+
+    return () => clearInterval(interval);
+  }, []);
+  return (
+    <View
+      style={{
+        flex: 1,
+        backgroundColor: '#000',
+      }}>
+      {Array.from({length: 100}).map((e, idx) => (
+        <Text style={{color: '#fff'}} key={idx}>
+          T{idx}: {t}
+        </Text>
+      ))}
+    </View>
+  );
+};
+
+const TestScreen2 = () => {
+  const [t, setT] = useState(0);
+
+  useEffect(() => {
+    const interval = setInterval(() => {
+      setT(lastT => lastT + 1);
+    }, 100);
+
+    return () => clearInterval(interval);
+  }, []);
+
+  return (
+    <View
+      style={{
+        flex: 1,
+        backgroundColor: '#000',
+      }}>
+      {Array.from({length: 100}).map((e, idx) => (
+        <Text style={{color: 'red'}} key={idx}>
+          T{idx}: {t}
+        </Text>
+      ))}
+    </View>
+  );
+};
+const TestScreenTab1 = () => {
+  return (
+    <TestNativeStack1.Navigator initialRouteName="screen1a">
+      <TestNativeStack1.Screen name="screen1a" component={TestScreen1} />
+      <TestNativeStack1.Screen name="screen1b" component={TestScreen2} />
+    </TestNativeStack1.Navigator>
+  );
+};
+
+const TestScreenTab2 = () => {
+  return (
+    <TestNativeStack2.Navigator initialRouteName="screen2a">
+      <TestNativeStack2.Screen name="screen2a" component={TestScreen2} />
+      <TestNativeStack2.Screen name="screen2b" component={TestScreen1} />
+    </TestNativeStack2.Navigator>
+  );
+};
+
+const App = () => {
+  return (
+    <NavigationContainer>
+      <TestBottomTabBar.Navigator
+        initialRouteName="tab1"
+        screenOptions={{
+          unmountOnBlur: true,
+        }}>
+        <TestBottomTabBar.Screen name="tab1" component={TestScreenTab1} />
+        <TestBottomTabBar.Screen name="tab2" component={TestScreenTab2} />
+      </TestBottomTabBar.Navigator>
+    </NavigationContainer>
+  );
+};
+
+export default App;

apps/test-examples/src/Test432.tsx

@@ -0,0 +1,72 @@
+import { Pressable, View, Button, Text } from 'react-native';
+
+import { NavigationContainer, useNavigation } from '@react-navigation/native';
+import {
+  NativeStackScreenProps,
+  createNativeStackNavigator,
+} from '@react-navigation/native-stack';
+import React, { useCallback } from 'react';
+
+type RootStackParamList = {
+  Home: undefined;
+  Settings: undefined;
+};
+type RootStackScreenProps<T extends keyof RootStackParamList> =
+  NativeStackScreenProps<RootStackParamList, T>;
+const HomeScreen = ({ navigation }: RootStackScreenProps<'Home'>) => {
+  const showSettings = useCallback(() => {
+    navigation.navigate('Settings');
+  }, [navigation]);
+  return (
+    <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
+      <Button onPress={showSettings} title={'Show settings'} />
+    </View>
+  );
+};
+
+const SettingsScreen = ({ navigation }: RootStackScreenProps<'Settings'>) => {
+  return (
+    <View style={{ flex: 1, alignItems: 'center', justifyContent: 'center' }}>
+      <Text>Settings</Text>
+    </View>
+  );
+};
+
+const RootStack = createNativeStackNavigator<RootStackParamList>();
+const RootNavigator = () => {
+  const navigation = useNavigation();
+  const headerRight = useCallback(
+    () => (
+      <Pressable
+        onPress={() => {
+          navigation.goBack();
+        }}>
+        <Text>Close</Text>
+      </Pressable>
+    ),
+    [navigation],
+  );
+  return (
+    <RootStack.Navigator screenOptions={{ headerShown: false }}>
+      <RootStack.Screen name="Home" component={HomeScreen} />
+      <RootStack.Screen
+        name="Settings"
+        component={SettingsScreen}
+        options={{
+          presentation: 'modal',
+          animation: 'slide_from_bottom',
+          headerShown: true,
+          headerRight: headerRight,
+        }}
+      />
+    </RootStack.Navigator>
+  );
+};
+
+export default function App() {
+  return (
+    <NavigationContainer>
+      <RootNavigator />
+    </NavigationContainer>
+  );
+}

ios/RNSScreenStack.mm

@@ -118,7 +118,6 @@ @implementation RNSScreenStackView {
   BOOL _invalidated;
   BOOL _isFullWidthSwiping;
   UIPercentDrivenInteractiveTransition *_interactionController;
-  BOOL _hasLayout;
   __weak RNSScreenStackManager *_manager;
   BOOL _updateScheduled;
 #ifdef RCT_NEW_ARCH_ENABLED
@@ -142,7 +141,6 @@ - (instancetype)initWithFrame:(CGRect)frame
 - (instancetype)initWithManager:(RNSScreenStackManager *)manager
 {
   if (self = [super init]) {
-    _hasLayout = NO;
     _invalidated = NO;
     _manager = manager;
     [self initCommonProps];
@@ -272,18 +270,9 @@ - (void)didMoveToWindow
 - (void)maybeAddToParentAndUpdateContainer
 {
   BOOL wasScreenMounted = _controller.parentViewController != nil;
-#ifdef RCT_NEW_ARCH_ENABLED
-  BOOL isScreenReadyForShowing = self.window;
-#else
-  BOOL isScreenReadyForShowing = self.window && _hasLayout;
-#endif
-  if (!isScreenReadyForShowing && !wasScreenMounted) {
-    // We wait with adding to parent controller until the stack is mounted and has its initial
-    // layout done.
-    // If we add it before layout, some of the items (specifically items from the navigation bar),
-    // won't be able to position properly. Also the position and size of such items, even if it
-    // happens to change, won't be properly updated (this is perhaps some internal issue of UIKit).
-    // If we add it when window is not attached, some of the view transitions will be bloced (i.e.
+  if (!self.window && !wasScreenMounted) {
+    // We wait with adding to parent controller until the stack is mounted.
+    // If we add it when window is not attached, some of the view transitions will be blocked (i.e.
     // modal transitions) and the internal view controler's state will get out of sync with what's
     // on screen without us knowing.
     return;
@@ -1076,7 +1065,6 @@ - (void)didUpdateReactSubviews
   // set yet, however the layout call is already enqueued on ui thread. Enqueuing update call on the
   // ui queue will guarantee that the update will run after layout.
   dispatch_async(dispatch_get_main_queue(), ^{
-    self->_hasLayout = YES;
     [self maybeAddToParentAndUpdateContainer];
   });
 }