Move EnableSyncDetachRootView quirk option from React.h to public QuirkSettings API

Co-authored-by: anupriya13 <54227869+anupriya13@users.noreply.github.com>

Author: Copilot

change/move-quirk-to-quirksettings-20250105000000.json

@@ -0,0 +1,7 @@
+{
+  "type": "prerelease",
+  "comment": "Move EnableSyncDetachRootView quirk option from React.h to public QuirkSettings API",
+  "packageName": "@rnw-dependencies",
+  "email": "noreply@microsoft.com",
+  "dependentChangeType": "patch"
+}

vnext/Microsoft.ReactNative/QuirkSettings.cpp

@@ -64,6 +64,12 @@ winrt::Microsoft::ReactNative::ReactPropertyId<bool> MapWindowDeactivatedToAppSt
   properties.Set(MapWindowDeactivatedToAppStateInactiveProperty(), value);
 }
 
+/*static*/ void QuirkSettings::SetEnableSyncDetachRootView(
+    winrt::Microsoft::ReactNative::ReactPropertyBag properties,
+    bool value) noexcept {
+  properties.Set(EnableSyncDetachRootViewProperty(), value);
+}
+
 winrt::Microsoft::ReactNative::ReactPropertyId<bool> SuppressWindowFocusOnViewFocusProperty() noexcept {
   winrt::Microsoft::ReactNative::ReactPropertyId<bool> propId{
       L"ReactNative.QuirkSettings", L"SuppressWindowFocusOnViewFocus"};
@@ -77,6 +83,12 @@ winrt::Microsoft::ReactNative::ReactPropertyId<bool> UseRuntimeSchedulerProperty
   return propId;
 }
 
+winrt::Microsoft::ReactNative::ReactPropertyId<bool> EnableSyncDetachRootViewProperty() noexcept {
+  static winrt::Microsoft::ReactNative::ReactPropertyId<bool> propId{
+      L"ReactNative.QuirkSettings", L"EnableSyncDetachRootView"};
+  return propId;
+}
+
 #pragma region IDL interface
 
 /*static*/ void QuirkSettings::SetMatchAndroidAndIOSStretchBehavior(
@@ -121,6 +133,12 @@ winrt::Microsoft::ReactNative::ReactPropertyId<bool> UseRuntimeSchedulerProperty
   ReactPropertyBag(settings.Properties()).Set(UseRuntimeSchedulerProperty(), value);
 }
 
+/*static*/ void QuirkSettings::SetEnableSyncDetachRootView(
+    winrt::Microsoft::ReactNative::ReactInstanceSettings settings,
+    bool value) noexcept {
+  ReactPropertyBag(settings.Properties()).Set(EnableSyncDetachRootViewProperty(), value);
+}
+
 #pragma endregion IDL interface
 
 /*static*/ bool QuirkSettings::GetMatchAndroidAndIOSStretchBehavior(ReactPropertyBag properties) noexcept {
@@ -153,4 +171,8 @@ winrt::Microsoft::ReactNative::ReactPropertyId<bool> UseRuntimeSchedulerProperty
   return properties.Get(UseRuntimeSchedulerProperty()).value_or(true);
 }
 
+/*static*/ bool QuirkSettings::GetEnableSyncDetachRootView(ReactPropertyBag properties) noexcept {
+  return properties.Get(EnableSyncDetachRootViewProperty()).value_or(false);
+}
+
 } // namespace winrt::Microsoft::ReactNative::implementation

vnext/Microsoft.ReactNative/QuirkSettings.h

@@ -39,6 +39,11 @@ struct QuirkSettings : QuirkSettingsT<QuirkSettings> {
   static bool GetMapWindowDeactivatedToAppStateInactive(
       winrt::Microsoft::ReactNative::ReactPropertyBag properties) noexcept;
 
+  static void SetEnableSyncDetachRootView(
+      winrt::Microsoft::ReactNative::ReactPropertyBag properties,
+      bool value) noexcept;
+  static bool GetEnableSyncDetachRootView(winrt::Microsoft::ReactNative::ReactPropertyBag properties) noexcept;
+
 #pragma region Public API - part of IDL interface
   static void SetMatchAndroidAndIOSStretchBehavior(
       winrt::Microsoft::ReactNative::ReactInstanceSettings settings,
@@ -65,6 +70,10 @@ struct QuirkSettings : QuirkSettingsT<QuirkSettings> {
       winrt::Microsoft::ReactNative::ReactInstanceSettings settings,
       bool value) noexcept;
 
+  static void SetEnableSyncDetachRootView(
+      winrt::Microsoft::ReactNative::ReactInstanceSettings settings,
+      bool value) noexcept;
+
 #pragma endregion Public API - part of IDL interface
 };
 

vnext/Microsoft.ReactNative/QuirkSettings.idl

@@ -64,6 +64,13 @@ namespace Microsoft.ReactNative
         "By default `react-native-windows` will use the new RuntimeScheduler."
         "Setting this to false will revert the behavior to previous scheduling logic.")
     static void SetUseRuntimeScheduler(ReactInstanceSettings settings, Boolean value);
+
+    DOC_STRING(
+        "QUIRK: Enable synchronous wait in DetachRootView for JS thread completion. "
+        "This flag re-enables the legacy runOnQueueSync call that can cause deadlocks "
+        "with Hermes GC. Only enable if removal of sync behavior breaks your application.")
+    DOC_DEFAULT("false")
+    static void SetEnableSyncDetachRootView(ReactInstanceSettings settings, Boolean value);
   }
 
 } // namespace Microsoft.ReactNative

vnext/Microsoft.ReactNative/ReactHost/React.h

@@ -251,12 +251,6 @@ struct ReactOptions {
   //! It is not safe to expose to Custom Function. Add this flag so we can turn it off for Custom Function.
   bool EnableNativePerformanceNow{true};
 
-  //! QUIRK: Enable synchronous wait in DetachRootView for JS thread completion.
-  //! This flag re-enables the legacy runOnQueueSync call that can cause deadlocks
-  //! with Hermes GC. Only enable if removal of sync behavior breaks your application.
-  //! Default: false (sync call is disabled to prevent deadlocks)
-  bool EnableSyncDetachRootView{false};
-
   ReactDevOptions DeveloperSettings = {};
 
   //! This controls the availability of various developer support functionality including

vnext/Microsoft.ReactNative/ReactHost/ReactInstanceWin.cpp

@@ -1516,7 +1516,8 @@ void ReactInstanceWin::DetachRootView(facebook::react::IReactRootView *rootView,
 
   // QUIRK: Legacy sync behavior can be re-enabled via EnableSyncDetachRootView option
   // The sync call was removed to prevent deadlocks with Hermes GC operations
-  if (m_options.EnableSyncDetachRootView) {
+  auto propBag = ReactPropertyBag(m_reactContext->Properties());
+  if (QuirkSettings::GetEnableSyncDetachRootView(propBag)) {
     // Legacy behavior: wait for JS thread to finish executing (can cause deadlocks)
     m_jsMessageThread.Load()->runOnQueueSync([]() {});
   }