put PR#41194 behind gating (facebook#41469)

Summary: Changelog: [Internal] PR#41194 (facebook#41194) introduces a new callsite to `RCTUnsafeExecuteOnMainQueueSync` in the module init path, which increases risk for deadlock. let's gate it Differential Revision: D51274859
philIip · Nov 14, 2023 · e1fba7e · e1fba7e
1 parent ad0f064
commit e1fba7e
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diff --git a/packages/react-native/React/Base/RCTBridge.h b/packages/react-native/React/Base/RCTBridge.h
@@ -61,6 +61,9 @@ void RCTEnableTurboModuleSyncVoidMethods(BOOL enabled);
 BOOL RCTTurboModuleSharedQueueEnabled(void);
 void RCTEnableTurboModuleSharedQueue(BOOL enabled);
 
+BOOL RCTUIManagerDispatchAccessibilityManagerInitOntoMain(void);
+void RCTUIManagerSetDispatchAccessibilityManagerInitOntoMain(BOOL enabled);
+
 typedef enum {
   kRCTBridgeProxyLoggingLevelNone,
   kRCTBridgeProxyLoggingLevelWarning,

diff --git a/packages/react-native/React/Base/RCTBridge.mm b/packages/react-native/React/Base/RCTBridge.mm
@@ -162,6 +162,17 @@ void RCTEnableTurboModuleSharedQueue(BOOL enabled)
   gTurboModuleEnableSharedQueue = enabled;
 }
 
+BOOL kDispatchAccessibilityManagerInitOntoMain = NO;
+BOOL RCTUIManagerDispatchAccessibilityManagerInitOntoMain(void)
+{
+  return kDispatchAccessibilityManagerInitOntoMain;
+}
+
+void RCTUIManagerSetDispatchAccessibilityManagerInitOntoMain(BOOL enabled)
+{
+  kDispatchAccessibilityManagerInitOntoMain = enabled;
+}
+
 @interface RCTBridge () <RCTReloadListener>
 @end
 

diff --git a/packages/react-native/React/Modules/RCTUIManager.m b/packages/react-native/React/Modules/RCTUIManager.m
@@ -181,7 +181,10 @@ - (void)setBridge:(RCTBridge *)bridge
   }
 
   // This dispatch_async avoids a deadlock while configuring native modules
-  dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INTERACTIVE, 0), ^{
+  dispatch_queue_t accessibilityManagerInitQueue = RCTUIManagerDispatchAccessibilityManagerInitOntoMain()
+      ? dispatch_get_main_queue()
+      : dispatch_get_global_queue(QOS_CLASS_USER_INTERACTIVE, 0);
+  dispatch_async(accessibilityManagerInitQueue, ^{
     [[NSNotificationCenter defaultCenter] addObserver:self
                                              selector:@selector(didReceiveNewContentSizeMultiplier)
                                                  name:@"RCTAccessibilityManagerDidUpdateMultiplierNotification"