From b44e1839ca7bddae467ef3aa015f0b689d4b3167 Mon Sep 17 00:00:00 2001
From: Samuel Susla <samuelsusla@meta.com>
Date: Tue, 12 Aug 2025 13:25:16 -0700
Subject: [PATCH] fix crash in adjustForMaintainVisibleContentPosition (#53208)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/53208

changelog: [internal]

When Fabric View Culling is enabled together with immediate state update, it may lead to a crash inside of `[RCTScrollViewComponentView _adjustForMaintainVisibleContentPosition]`.
When doing immediate state update, we can avoid calling `[RCTScrollViewComponentView _adjustForMaintainVisibleContentPosition]` altogether to avoid the crash.

Reviewed By: lenaic

Differential Revision: D80000362

fbshipit-source-id: 123b70aa31edb14a99bb968648eb8b8aac84afb6
---
 .../ScrollView/RCTScrollViewComponentView.mm   | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTScrollViewComponentView.mm b/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTScrollViewComponentView.mm
index fc33f648bb6..671f3387d03 100644
--- a/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTScrollViewComponentView.mm
+++ b/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTScrollViewComponentView.mm
@@ -119,6 +119,10 @@ RCTSendScrollEventForNativeAnimations_DEPRECATED(UIScrollView *scrollView, NSInt
   // Once an accessibility API is used, view culling will be disabled for the entire session.
   BOOL _isAccessibilityAPIUsed;
 
+  // Flag to temporarily disable maintainVisibleContentPosition adjustments during immediate state updates
+  // to prevent conflicts between immediate content offset updates and visible content position logic
+  BOOL _avoidAdjustmentForMaintainVisibleContentPosition;
+
   RCTVirtualViewContainerState *_virtualViewContainerState;
 }
 
@@ -640,6 +644,11 @@ static inline UIViewAnimationOptions animationOptionsWithCurve(UIViewAnimationCu
     return;
   }
 
+  BOOL enableImmediateUpdateModeForContentOffsetChanges =
+      ReactNativeFeatureFlags::enableImmediateUpdateModeForContentOffsetChanges();
+
+  _avoidAdjustmentForMaintainVisibleContentPosition = enableImmediateUpdateModeForContentOffsetChanges;
+
   auto contentOffset = RCTPointFromCGPoint(_scrollView.contentOffset);
   BOOL isAccessibilityAPIUsed = _isAccessibilityAPIUsed;
   _state->updateState(
@@ -655,9 +664,10 @@ static inline UIViewAnimationOptions animationOptionsWithCurve(UIViewAnimationCu
             UIAccessibilityIsVoiceOverRunning() || UIAccessibilityIsSwitchControlRunning() || isAccessibilityAPIUsed;
         return std::make_shared<const ScrollViewShadowNode::ConcreteState::Data>(newData);
       },
-      ReactNativeFeatureFlags::enableImmediateUpdateModeForContentOffsetChanges()
-          ? EventQueue::UpdateMode::unstable_Immediate
-          : EventQueue::UpdateMode::Asynchronous);
+      enableImmediateUpdateModeForContentOffsetChanges ? EventQueue::UpdateMode::unstable_Immediate
+                                                       : EventQueue::UpdateMode::Asynchronous);
+
+  _avoidAdjustmentForMaintainVisibleContentPosition = NO;
 }
 
 - (void)prepareForRecycle
@@ -1057,7 +1067,7 @@ static inline UIViewAnimationOptions animationOptionsWithCurve(UIViewAnimationCu
 - (void)_adjustForMaintainVisibleContentPosition
 {
   const auto &props = static_cast<const ScrollViewProps &>(*_props);
-  if (!props.maintainVisibleContentPosition) {
+  if (!props.maintainVisibleContentPosition || _avoidAdjustmentForMaintainVisibleContentPosition) {
     return;
   }