fix(iOS, Tabs): tab screen height when tabs are rendered dynamically

apps/src/tests/Test3425.tsx

@@ -0,0 +1,30 @@
+import React, { useState } from 'react';
+import { Button, View } from 'react-native';
+import Colors from '../shared/styling/Colors';
+import { TestBottomTabs } from '.';
+
+export default function App() {
+  const [index, setIndex] = useState(0);
+  return (
+    <View
+      style={{
+        flex: 1,
+        paddingHorizontal: 20,
+        paddingVertical: 100,
+        backgroundColor: Colors.BlueLight40,
+      }}>
+      {index === 0 ? (
+        <View
+          style={{
+            flex: 1,
+            justifyContent: 'center',
+            alignItems: 'center',
+          }}>
+          <Button title="Go to Bottom Tabs" onPress={() => setIndex(1)} />
+        </View>
+      ) : (
+        <TestBottomTabs />
+      )}
+    </View>
+  );
+}

apps/src/tests/index.ts

@@ -162,6 +162,7 @@ export { default as Test3342 } from './Test3342';
 export { default as Test3346 } from './Test3346';
 export { default as Test3369 } from './Test3369';
 export { default as Test3379 } from './Test3379';
+export { default as Test3425 } from './Test3425';
 export { default as TestScreenAnimation } from './TestScreenAnimation';
 export { default as TestScreenAnimationV5 } from './TestScreenAnimationV5';
 export { default as TestHeader } from './TestHeader';

ios/bottom-tabs/host/RNSBottomTabsHostComponentView.mm

@@ -155,6 +155,24 @@ - (void)reactAddControllerToClosestParent:(UIViewController *)controller
   }
 }
 
+#if RCT_NEW_ARCH_ENABLED
+
+// On Fabric, when tabs are rendered dynamically, tab screens receive incorrect frame from UIKit layout
+// (frame matches full window size instead of the size of the host). To mitigate this, we override
+// `layoutSubviews` and assign correct frame ourselves.
+// TODO: investigate why we receive incorrect frame, fix and remove this workaround
+- (void)layoutSubviews
+{
+  RCTAssert(
+      self.subviews.count == 1,
+      @"[RNScreens] Unexpected number of subviews in RNSBottomTabsHostComponentView. Expected 1, actual: %lu.",
+      static_cast<unsigned long>(self.subviews.count));
+
+  [self.subviews[0] setFrame:self.bounds];
+}
+
+#endif // RCT_NEW_ARCH_ENABLED
+
 #pragma mark - RNSScreenContainerDelegate
 
 - (void)updateContainer