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The problem is due to a bug in the way the debugger interacts with CET. The error goes away when the following line is added to the project file:
<CetCompat>false</CetCompat>
After upgrading to .NET 9, simple C# statement triggers fatal error in Visual Studio 2022 when Control-C is used to exit
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Goober McSnidemouth
0
Reputation points
I'm using Visual Studio 2022 (17.12.0 - preview 1.0)
I noticed that .NET 9 is now available as an option in Visual Studio 2022 so I tried upgrading from .NET 8. My applications continue to run as expected, with one problem: I'm getting a fatal error when halting my console applications using Control-C, or when closing the console using the X close button in the upper right corner.
Here's the error I'm receiving:
This applies to all of my console applications that make use of the WebBuilder class. The simplest program that will consistently trigger the error is:
internal class Startup
{
public static async Task Main(string[] args)
{
await WebApplication.CreateBuilder().Build().RunAsync();
}
}
This code was entered into a new console project, in a new solution, where the top line in the project file has been changed to:
<Project Sdk="Microsoft.NET.Sdk.Web">
In addition, launchsettings.json has been deleted to prevent Brave browser from launching when the app is run. The error still occurs even if this file is present; I just deleted it to remove Brave from the equation.
The app itself works fine. It's only the shutdown, when triggered by Control-C or clicking the close button (X) in the console window, that immediately triggers a fatal error with no hints written to the Event Log.
Interestingly, when the app shuts itself down using IHostApplicationLifetime.StopApplication, the shutdown is smooth. There are no errors.
Running the application from the Powershell command line instead of the debugger causes the error to go away. The error only manifests when the debugger is attached.
Reverting the project from .NET 9 back to .NET 8 also causes the error to go away.
Googling this particular error turns up nothing. Any ideas?
Developer technologies Visual Studio Other
Developer technologies C#
11,567 questions
{count} votes
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David Lowndes 2,640 Reputation points MVP2024-08-20T20:43:53.7866667+00:00 I suggest that you report it as a bug using VS's "Report a Problem" facility and see what Microsoft have to say about it.
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Goober McSnidemouth 0 Reputation points
2024-08-21T13:55:55.1433333+00:00 @David Lowdndes: Even that fails. Attempting to report a problem launches a web browser and gives the error, "Oops, we've lost your connection to Visual Studio." I've pretty much given up at this point. The product is just fundamentally broken at every level and I don't really have the time or inclination to pursue further. It was a fun experiment but VS just isn't for me any more.
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Anonymous2024-08-22T09:22:25.2733333+00:00 Hi @Goober McSnidemouth , Is this an asp.net core project? I haven't tested this problem yet. Can you tell me a reproducible process? Because you are using the test version in the preview version, some problems require multiple tests. You mentioned that you modified the current project directly, maybe it's because of the project problem.
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David Lowndes 2,640 Reputation points MVP
2024-08-22T09:53:17.35+00:00 Using your repro steps:
- create a new C# console project
- add the line of code you showed (making Main async)
- changing the project setting by appending ".Web"
I'm unable to reproduce your issue.
Building both with .NET 8 & the preview .NET 9 on VS 2022 17.12.0 Preview 1 give rise to the output like this for me (no message box appears):
info: Microsoft.Hosting.Lifetime[14] Now listening on: https://localhost:61197 info: Microsoft.Hosting.Lifetime[14] Now listening on: http://localhost:61198 info: Microsoft.AspNetCore.Mvc.Infrastructure.DefaultActionDescriptorCollectionProvider[1] No action descriptors found. This may indicate an incorrectly configured application or missing application parts. To learn more, visit https://aka.ms/aspnet/mvc/app-parts info: Microsoft.Hosting.Lifetime[0] Application started. Press Ctrl+C to shut down. info: Microsoft.Hosting.Lifetime[0] Hosting environment: Development info: Microsoft.Hosting.Lifetime[0] Content root path: C:\Users\David\source\repos\ConsoleApp1 info: Microsoft.AspNetCore.Hosting.Diagnostics[1] Request starting HTTP/2 GET https://localhost:61197/ - - - info: Microsoft.AspNetCore.Hosting.Diagnostics[2] Request finished HTTP/2 GET https://localhost:61197/ - 404 0 - 315.6155ms info: Microsoft.AspNetCore.Hosting.Diagnostics[16] Request reached the end of the middleware pipeline without being handled by application code. Request path: GET https://localhost:61197/, Response status code: 404 info: Microsoft.Hosting.Lifetime[0] Application is shutting down... C:\Users\David\source\repos\ConsoleApp1\bin\Debug\net9.0\ConsoleApp1.exe (process 16080) exited with code 0 (0x0). -
Goober McSnidemouth 0 Reputation points
2024-08-22T13:45:50.7966667+00:00 You're doing everything right.
Note that the error only occurs when the net9.0 framework tag is used; net8.0 works fine. Also, the error only occurs when running in the Visual Studio debugger; Running by double-clicking the executable works fine.
Also note the error also occurs if the app is terminated using the close button in the upper right corner of the console window. So it's not just Control-C that triggers it. And again, it only happens when the debugger is attached.
For what it's worth, I'm running on Windows 11 with all updates installed.
If you've done all of this and still can't reproduce the problem, the error must be on my side. I'm not sure what it could be though. It's a clean installation of windows. Nothing installed except Visual Studio 2022 and VS Code.
The only other information I can offer you is that the crash occurs before this line is written to the console log:
info: Microsoft.Hosting.Lifetime[0] Application is shutting down...
I never see that line when I get the crash. When registering an actual service, instead of just using an empty builder as we're doing in this test scenario, the Dispose() method is never called. So as far as I can tell, the shutdown signal is never sent to the framework where it can be processed.
It would be nice to be able to set a breakpoint somewhere and step through to see exactly which line of code is causing the crash, but that's a bit beyond my level of technical expertise. If you want to tell me the code to intercept a Control-C and set a breakpoint and step through, I'll do my best to identify the exact line -- but I'm guessing the crash occurs before I'd even be able to hit the breakpoint on Control-C. It has something to do with the debugger's interaction with the process. Control-C is crashing it somehow.
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David Lowndes 2,640 Reputation points MVP
2024-08-22T17:47:16.3866667+00:00 The only difference I can spot is that I've tried it on Windows 10. You can see from the output that I was using .NET 9.0 and I was running it under the debugger by pressing F5 from VS.
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Goober McSnidemouth 0 Reputation points
2024-08-22T19:18:41.5266667+00:00 Seems to be a Visual Studio debugger glitch that only affects me. Wish I had some clue as to what's causing it. It's just a standard Windows 11 VM with Visual Studio installed. Not sure what it could be. Thanks for trying in any case.
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Anonymous
2024-08-23T09:53:55.2733333+00:00 https://developercommunity.visualstudio.com/t/vs2019-a-fatal-error-occurred-and-debugging-needs/596444 This may be caused by starting the wrong debugging engine. I suggest you try it in a new project. If you can reproduce it, share the animated image so that we can see. I also suggest that you can delete the project cache, especially the hidden .vs folder, then rebuild and debug again. You can't seem to report it, you can try this .NET entry Developer Community (visualstudio.com) After you submit your feedback, add the Visual Studio related tags
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Goober McSnidemouth 0 Reputation points
2024-08-27T21:38:10.1833333+00:00