Dev reload crashes with SurfaceHandler::setUIManager assert (link_.status != Status::Running) on RN 0.82.1 + RNN 8.6.0 #54845

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1. solonifer

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   on Dec 10, 2025
2. react-native-bot

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   Needs: ReproThis issue could be improved with a clear list of steps to reproduce the issue.This issue could be improved with a clear list of steps to reproduce the issue.

   on Dec 10, 2025
3. react-native-bot commented on Dec 10, 2025

   

   react-native-bot

   on Dec 10, 2025

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   Missing reproducer: We could not detect a reproducible example in your issue report. Reproducers are mandatory and we can accept only one of those as a valid reproducer:
   

   • For majority of bugs: send us a Pull Request with the RNTesterPlayground.js edited to reproduce your bug.
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4. react-native-bot

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   on Dec 10, 2025
5. migueldaipre commented on Dec 15, 2025

   

   migueldaipre

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   Hey @solonifer, please, a basic reproducer is necessary for us to help.

   It seems to me that your issue is not directly related to React Native Core.

   Please add a minimal basic reproducer that simulates the issue without third-party libraries.
6. migueldaipre

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   Type: InvalidThis issue does not belong here. Applying this label will cause issue to be closed.This issue does not belong here. Applying this label will cause issue to be closed.

   on Dec 15, 2025
7. react-native-bot commented on Dec 15, 2025

   

   react-native-bot

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   Invalid issue: This issue is not valid, either is not a bug in React Native, it doesn't match any of the issue template, or we can't help further with this.
8. react-native-bot

   closed this as completedon Dec 15, 2025
9. reeywhaar commented on Sep 22, 2026

   

   reeywhaar

   on Sep 22, 2026

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   Hitting this too, on a plain dev reload — worth saying it isn't specific to Fast Refresh, a Cmd+R does it just as reliably.

   Environment

   react-native	0.85.3
   react-native-navigation	8.8.11
   react	19.2.3
   New architecture	enabled (bridgeless)
   Hermes	enabled
   Platform	iOS, simulator (iPhone 17, iOS 26.5) and device
   Xcode	26.5 (17F42)

   __assert_rtn
   facebook::react::SurfaceHandler::setUIManager(const UIManager*)
   facebook::react::Scheduler::unregisterSurface(const SurfaceHandler&)
   -[RCTScheduler unregisterSurface:]
   -[RCTSurfacePresenter unregisterSurface:]
   -[RCTFabricSurface dealloc]
   _Block_release          ← com.apple.root.user-interactive-qos

   The surface is deallocated on a background queue while it is still Running. What I think happens:

   1. RCTHost::_reloadWithShouldRestartSurfaces: restarts every attached surface, capturing it strongly:

      [_instance callFunctionOnBufferedRuntimeExecutor:[surface](facebook::jsi::Runtime &_) { [surface start]; }];

      So a surface the app is about to release is kept alive until the new bundle arrives.
   2. The bundle runs, react-native-navigation tears the old screens down, and -[RCTSurfaceHostingView dealloc] calls [_surface stop] — which returns immediately, because the status is not Running yet.
   3. The buffered executor flushes, [surface start] runs, and its dispatch_async(QOS_CLASS_USER_INTERACTIVE) block (also a strong self) sets the status to Running.
   4. That block finishes and drops the last reference right there, on that queue → dealloc → unregisterSurface → assert.

   __weak RCTFabricSurface *weakSurface = surface;
   [_instance callFunctionOnBufferedRuntimeExecutor:[weakSurface](facebook::jsi::Runtime &_) { [weakSurface start]; }];

   The reload path never got the same treatment.

   What helped me. We consume the prebuilt React core, so patch-package cannot reach RCTHost.mm — I swizzled the reload to skip the restart instead. With react-native-navigation the reloaded bundle calls setRoot and builds fresh surfaces anyway, so the restart had nothing to do:

   diff --git a/ios/KidsoutMobile/AppDelegate.swift b/ios/KidsoutMobile/AppDelegate.swift
   --- a/ios/KidsoutMobile/AppDelegate.swift
   +++ b/ios/KidsoutMobile/AppDelegate.swift
   @@ -1,4 +1,5 @@
    import UIKit
   +import ObjectiveC
    import React
    import ReactAppDependencyProvider
    import ReactNativeNavigation
   @@ -13,6 +14,9 @@ typealias Dictionary = Swift.Dictionary
    @main
    class AppDelegate: RNNAppDelegate {
      override func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
   +#if DEBUG
   +    DevReload.dontRestartSurfaces()
   +#endif
        self.reactNativeDelegate = ReactNativeDelegate()
   
        // Configure Firebase
   @@ -76,6 +80,38 @@ class AppDelegate: RNNAppDelegate {
    }
   
   
   +#if DEBUG
   +/**
   + A reload restarts every surface RN still has attached, holding each one strongly until the new
   + bundle arrives and then starting it from a background block that drops the last reference —
   + `-[RCTFabricSurface dealloc]` runs there with the handler running, and `SurfaceHandler` aborts.
   + */
   +enum DevReload {
   +  static func dontRestartSurfaces() {
   +    let host = NSClassFromString("RCTHost")
   +    let reloadSelector = NSSelectorFromString("didReceiveReloadCommand")
   +    let restartSelector = NSSelectorFromString("_reloadWithShouldRestartSurfaces:")
   +
   +    guard let host,
   +          let reload = class_getInstanceMethod(host, reloadSelector),
   +          class_getInstanceMethod(host, restartSelector) != nil,
   +          let restart = class_getMethodImplementation(host, restartSelector)
   +    else {
   +      NSLog("DevReload: RCTHost no longer answers didReceiveReloadCommand — reload crashes again")
   +      return
   +    }
   +
   +    typealias Reload = @convention(c) (AnyObject, Selector, ObjCBool) -> Void
   +    let withoutRestart = unsafeBitCast(restart, to: Reload.self)
   +    let replacement: @convention(block) (AnyObject) -> Void = { target in
   +      withoutRestart(target, restartSelector, false)
   +    }
   +    method_setImplementation(reload, imp_implementationWithBlock(replacement))
   +  }
   +}
   +#endif
   +
    class ReactNativeDelegate: RCTDefaultReactNativeFactoryDelegate {
      override func sourceURL(for bridge: RCTBridge) -> URL? {
        self.bundleURL()

   Reloads are crash free at least, though still, the whole stack reloads.

   What I think the actual fix is — untested here for the reason above, but it is the same change #48213 made to createSurface:

      for (RCTFabricSurface *surface in [self _getAttachedSurfaces]) {
        [surface resetWithSurfacePresenter:self.surfacePresenter];
        if (shouldRestartSurfaces) {
   -      [_instance callFunctionOnBufferedRuntimeExecutor:[surface](facebook::jsi::Runtime &_) { [surface start]; }];
   +      __weak RCTFabricSurface *weakSurface = surface;
   +      [_instance callFunctionOnBufferedRuntimeExecutor:[weakSurface](facebook::jsi::Runtime &_) { [weakSurface start]; }];
        }
      }

   One dead end: holding the surface in -[RNNReactView dealloc] past the restart does nothing. RCTHost's lambda owns it until the bundle loads, and that is not a delay you can outlast.