Aspire, locking after attempting hot reload

[rippo]

What happened?

When trying to use Aspire and a simple frontend MVC solution and a minimal backend project I keep getting a process that does not close.

If I stop the code and rebuild and start, I get a file is locked issue and the only way out is to close the project and reopen OR manually kill the process.

See attached screens, now this does not always happen but happens enough to make mty life difficult. See images for moere info.

Weirdly its not always the “Apphost” process, sometimes its the frontend of backend.

Hot reload is also quite hit and miss and more times than not I have to hit CTRL + SHIFT + F5 x2 to restart.

Support ticket #7464105

Ticet Update

I have enabled tracing in Rider and managed to catch the error and have uploaded the ZIP file to JetBrains

Steps to reproduce

1. Create an Aspire project
2. Create an minimal API backend project
3. Create an MVC project

Expected behavior

I expect never have to kill a windows process to get rider to build and run the solution

JetBrains Rider version

2025.1 RC1

.NET Aspire plugin version

1.7.8

.NET Aspire version

9.1

.NET version

9.0

Operating System

Windows

Link to a test project to reproduce the bug

No response

Additional context

No response

[rafaelldi]

@rippo Hello! Thanks for the report.

Hot reload is also quite hit and miss and more times than not I have to hit CTRL + SHIFT + F5 x2 to restart.

The plugin uses the mechanism from the Rider itself for hot reloading. So, I can't do anything in the plugin and would recommend describing particular fault cases in our tracker https://youtrack.jetbrains.com/issues/RIDER, my colleagues will take a look.

I have some questions regarding your problem.

When trying to use Aspire and a simple frontend MVC solution and a minimal backend project

1. Is the problem reproducible with the .NET Aspire Starter app template solution? Or only with your solution?

If I stop the code and rebuild and start

2. Just to be sure, do you stop, rebuild and start via Rider?

3. In your screenshot I see the Common.dll, is it shared between the two projects? Can you please check what the process uses it (it can be, for example, done with File Locksmith utility)?

[rippo]

Ho @rafaelldi thanks for looking into this.

1. Not sure, I will take a look later and get back to you, caught up in other client work ATM. However this does happen on three different solutions.

2. I stop and start using UI, stop using short cuts, stop one project, stop all three. I have tried various routes. Only killing the process OR closing rider works

3. Since filling the initial bug with JetBrains I have introduce a third common project. In the case of the screen shot above it happend to lock that process. Sometimes its the frontend, or backend or even the apphost projects. That bit is hit and miss.

Next time it locks I will use the File locksmith utility and get back to you.

[rippo]

I have been using aspire 9.2 and Rider 2025.1 for 2 days and only once has the rebuild been unsucessful due to a port in use (not file locking).

Opened Locksmith on the apphost but nothing was locking it. After killing the apphost process everything worked.

Will keep monitoring and keep you updated.

[rippo]

Hi I have spent a day working with aspire and rider and just hit

>Microsoft.Common.CurrentVersion.targets(5062,5): Warning MSB3026 : Could not copy 
   "D:\Projects\Websites\Meal.Analyser.Ai\Common\bin\Debug\net9.0\Common.dll" to 
   "bin\Debug\net9.0\Common.dll". Beginning retry 1 in 1000ms. The process cannot access the file 
    'D:\Projects\Websites\Meal.Analyser.Ai\Frontend\bin\Debug\net9.0\Common.dll' 
   because it is being used by another process. The file is locked by: "JetBrains JetBrains.Debugger.Worker (31836), 
   Frontend (34076)"

This is trying to "apply the changes", the window popped up "applying changes" but hung. I clicked cancel, stopped the build and now can't restart or rebuild without kill the processes

[rafaelldi]

@rippo Thank you! I will check this. But I'm not sure about the Frontend.exe process, could you please also see where it comes from?

[rippo]

The Aspire project has a "front end MVC", a "back end API" project.
The both share a "common" library

[rippo]

OK its locked again but is showing different results.

1>Microsoft.Common.CurrentVersion.targets(5363,5): Warning MSB3026 : Could not copy 
  "D:\Projects\Websites\Meal.Analyser.Ai\Frontend\obj\Debug\net9.0\apphost.exe" to 
  "bin\Debug\net9.0\Frontend.exe". Beginning retry 1 in 1000ms. The process cannot access the file 
  'D:\Projects\Websites\Meal.Analyser.Ai\Frontend\bin\Debug\net9.0\Frontend.exe' 
   because it is being used by another process. The file is locked by: "Frontend (23944)"

Been working on this project all day and this is the first time this has happened, so its not the end of the world!