[HotReload] Control + F5 break hotreload in the following debug sessions

[v-reinawang]

REGRESSION INFO: Repro in Nov release C# DK 1.90.2(C#2.110.4)

INSTALL STEPS

1. OS: window x64
2. Install the SDK 10.0.102
3. Install VS Code insiders - 1.109.0
4. Install Jan prerelease 2 prerelease C# DK1.92.5(include C#2.112.45)

REPRO STEPS

1. Go to Settings > Search 'Hot Reload' >Check "Enables C# Hot Reload while debugging“
2. Open VS Code > Create .NET Project > ASP.NET Core Web App (Razor Pages)
3. Right click the project > Debug > Start without Debugging > Stop running after the project has successfully started.
4. Right click the project > Debug > Start New Instance > Go to Index.cshtml and change "Welcome" to "Welcome,aaa" > Press Hot Reload button.

ACTUAL
The Hot Reload output window displays an error and a warning. Although it says "Code changes were successfully applied.", the browser page does not show the new changes.
If refresh the browser, the new changes still can't be displayed normally.

2026-01-20 13:33:21.861 [error] WebApplication1 (net10.0): Update batch #0 failed with error: Pipe is broken.
2026-01-20 13:33:21.861 [warning] WebApplication1 (net10.0): Further changes won't be applied to this process.

EXPECTED
There are no errors or warnings in the OUTPUT, and the page can be updated.

[v-elenafeng]

@LittleLittleCloud @JakeRadMSFT Hot reload doesn't work afte running the project without debugging and then running it again in debug mode.

[Susie-1989]

This issue still reproduces in Feb prerelease 1 C# DK2.11.4(include C#2.121.32)

[LittleLittleCloud]

Confirmed that this issue applies to hotreload for all .NET proejcts. If you start a Non-debug sesssion first, all hotreload sessions from the following debug sessions will be broken unless you reload VSCode.

Wondering if it's related to the vsdbg exception from vsCustomMessage request. I saw this request every time when I start a non-debug session, and once this exception appears, all the following hotreload session fails.

VsDbgException from non-debug session

2026-02-09 14:32:09.185 [info]  WebApplication2 (net10.0): Capabilities: 'Baseline AddMethodToExistingType AddStaticFieldToExistingType AddInstanceFieldToExistingType NewTypeDefinition ChangeCustomAttributes UpdateParameters GenericUpdateMethod GenericAddMethodToExistingType GenericAddFieldToExistingType AddFieldRva AddExplicitInterfaceImplementation'.
2026-02-09 14:32:09.188 [info]  [ProjectHotReloadSession-WebApplication2] Initial updates applied successfully
2026-02-09 14:32:09.189 [info]  [ProjectHotReloadSession-WebApplication2] Hot reload client connection established successfully
2026-02-09 14:32:09.326 [info]  Exception thrown for Apply code updates: 0x80131500 - Error processing 'vsCustomMessage' request. Unknown Error: 0x8007139f
2026-02-09 14:32:09.327 [info]  Stack trace for VsDbg.VsDbgException:
   at VsDbg.BrokeredServices.Services.HotReloadVsdbgEngineService.SendMessageAsync[T](ManagedEditAndContinueMessage message, CancellationToken cancellationToken)
   at VsDbg.BrokeredServices.Services.HotReloadVsdbgEngineService.GetAvailabilityAsync(Guid moduleVersionId, CancellationToken cancellationToken)
2026-02-09 14:32:12.568 [info]  WebApplication2 (.NETCoreApp,Version=v10.0): Connected to refresh server.

Pipe broken after VsDbgException appears

2026-02-09 14:35:15.028 [info]  AspireApp6.ApiService (net9.0): Sending update batch #0
2026-02-09 14:35:15.033 [error]  AspireApp6.ApiService (net9.0): Update batch #0 failed with error: Pipe is broken.
2026-02-09 14:35:15.035 [info]  AspireApp6.ApiService (net9.0): Update batch #0 exception stack trace:    at System.IO.Pipes.PipeStream.WriteAsyncCore(ReadOnlyMemory`1 buffer, CancellationToken cancellationToken)
   at System.IO.Pipes.PipeStream.WriteAsync(Byte[] buffer, Int32 offset, Int32 count, CancellationToken cancellationToken)
   at Microsoft.DotNet.HotReload.StreamExtesions.WriteAsync(Stream stream, Byte value, CancellationToken cancellationToken)
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine)
   at Microsoft.DotNet.HotReload.StreamExtesions.WriteAsync(Stream stream, Byte value, CancellationToken cancellationToken)
   at Microsoft.DotNet.HotReload.DefaultHotReloadClient.<>c__DisplayClass24_0`1.<<SendAndReceiveUpdateAsync>g__WriteRequestAsync|1>d.MoveNext()
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine)
   at Microsoft.DotNet.HotReload.DefaultHotReloadClient.<>c__DisplayClass24_0`1.<SendAndReceiveUpdateAsync>g__WriteRequestAsync|1(CancellationToken cancellationToken)
   at Microsoft.DotNet.HotReload.DefaultHotReloadClient.<>c__DisplayClass24_0`1.<<SendAndReceiveUpdateAsync>g__SendAndReceiveAsync|0>d.MoveNext()
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine)
   at Microsoft.DotNet.HotReload.DefaultHotReloadClient.<>c__DisplayClass24_0`1.<SendAndReceiveUpdateAsync>g__SendAndReceiveAsync|0(Int32 batchId, CancellationToken cancellationToken)
   at Microsoft.DotNet.HotReload.HotReloadClient.SendAndReceiveUpdateAsync[TResult](Func`3 send, Boolean isProcessSuspended, TResult suspendedResult, CancellationToken cancellationToken)
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine)
   at Microsoft.DotNet.HotReload.HotReloadClient.SendAndReceiveUpdateAsync[TResult](Func`3 send, Boolean isProcessSuspended, TResult suspendedResult, CancellationToken cancellationToken)
   at Microsoft.DotNet.HotReload.DefaultHotReloadClient.SendAndReceiveUpdateAsync[TRequest](TRequest request, Boolean isProcessSuspended, CancellationToken cancellationToken)
   at Microsoft.DotNet.HotReload.DefaultHotReloadClient.ApplyManagedCodeUpdatesAsync(ImmutableArray`1 updates, Boolean isProcessSuspended, CancellationToken cancellationToken)
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine)
   at Microsoft.DotNet.HotReload.DefaultHotReloadClient.ApplyManagedCodeUpdatesAsync(ImmutableArray`1 updates, Boolean isProcessSuspended, CancellationToken cancellationToken)
   at Microsoft.DotNet.HotReload.HotReloadClients.ApplyManagedCodeUpdatesAsync(ImmutableArray`1 updates, Boolean isProcessSuspended, Boolean isInitial, CancellationToken cancellationToken)
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine)
   at Microsoft.DotNet.HotReload.HotReloadClients.ApplyManagedCodeUpdatesAsync(ImmutableArray`1 updates, Boolean isProcessSuspended, Boolean isInitial, CancellationToken cancellationToken)
   at Microsoft.VisualStudio.ProjectSystem.HotReload.VSCode.ProjectHotReloadSession.ApplyUpdatesAsync(ImmutableArray`1 updates, CancellationToken cancellationToken)
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.Start[TStateMachine](TStateMachine& stateMachine)
   at Microsoft.VisualStudio.ProjectSystem.HotReload.VSCode.ProjectHotReloadSession.ApplyUpdatesAsync(ImmutableArray`1 updates, CancellationToken cancellationToken)
   at System.RuntimeMethodHandle.InvokeMethod(ObjectHandleOnStack target, Void** arguments, ObjectHandleOnStack sig, BOOL isConstructor, ObjectHandleOnStack result)
   at System.RuntimeMethodHandle.InvokeMethod(ObjectHandleOnStack target, Void** arguments, ObjectHandleOnStack sig, BOOL isConstructor, ObjectHandleOnStack result)
   at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
   at System.Reflection.MethodBaseInvoker.InvokeDirectByRefWithFewArgs(Object obj, Span`1 copyOfArgs, BindingFlags invokeAttr)
   at System.Reflection.MethodBaseInvoker.InvokeWithFewArgs(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at StreamJsonRpc.TargetMethod.InvokeAsync(CancellationToken cancellationToken)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
   at Microsoft.VisualStudio.Threading.NonConcurrentSynchronizationContext.ProcessQueueAsync()
   at System.Threading.ExecutionContext.RunFromThreadPoolDispatchLoop(Thread threadPoolThread, ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Runtime.CompilerServices.AsyncTaskMethodBuilder`1.AsyncStateMachineBox`1.ExecuteFromThreadPool(Thread threadPoolThread)
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
   at System.Threading.PortableThreadPool.WorkerThread.WorkerThreadStart()
   at System.Threading.Thread.StartCallback()
--- End of stack trace from previous location ---
   at Microsoft.DotNet.HotReload.StreamExtesions.WriteAsync(Stream stream, Byte value, CancellationToken cancellationToken)
   at Microsoft.DotNet.HotReload.DefaultHotReloadClient.<>c__DisplayClass24_0`1.<<SendAndReceiveUpdateAsync>g__WriteRequestAsync|1>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.DotNet.HotReload.DefaultHotReloadClient.<>c__DisplayClass24_0`1.<<SendAndReceiveUpdateAsync>g__SendAndReceiveAsync|0>d.MoveNext()
2026-02-09 14:35:15.035 [warning]  AspireApp6.ApiService (net9.0): Further changes won't be applied to this process.

[plnelson]

This is an internal issue in the debug engine - Concord. I have a local fix.