[.NET6] Referencing Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation breaks hot reload for .cshtml files

[BrightSoul]

Similar to issue #38809 but this is about regular Razor views, not Blazor components.

Here's the repro steps.

• Create a new project with dotnet new mvc
• Reference the razor view runtime compilation package with dotnet add package Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation
• Issue: hot reload is no longer watching changes done to .cshtml files. Verify it by running dotnet watch --list. All .cshtml files are no longer listed in the output. Here's a sample output.

> dotnet watch --list
E:\myproject\Controllers\HomeController.cs
E:\myproject\Models\ErrorViewModel.cs
E:\myproject\Program.cs
E:\myproject\MyProject.csproj
E:\myproject\Views\Shared\_Layout.cshtml.css <-- All .cshtml files from /Views are missing
E:\myproject\wwwroot\css\site.css
E:\myproject\wwwroot\favicon.ico
...

I would happily do without the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation package if OmniSharp issue #4822: integrate debugging with dotnet watch was solved. I'm a VSCode user and I would like to use dotnet watch all the time for development but I can't because the debugger won't attach automatically when the process is restarted.

[pranavkm]

RuntimeCompilation and hot reload for cshtml are effectively trying to solve the same problem. As a result, dotnet-watch opts out of watching .cshtml files if the runtime compilation package is reference. That said, you should be able to hit refresh in the browser and see changes to your cshtml files as it has worked in earlier versions of .NET.

[BrightSoul]

RuntimeCompilation and hot reload for cshtml are effectively trying to solve the same problem

Hot reload is also responsible for refreshing the browser page and that stops happening when the RuntimeCompilation package is referenced. That's the issue.
Instead, it should keep refreshing the page even if the compilation step is performed by the RuntimeCompilation package.

It's underwhelming to hear this is "by design" since there's still no complete solution.

• With hot reload, we don't get the debugger automatically attached;
• With the RuntimeCompilation package, the browser page won't reload automatically.
• They can't be used together.

[ghost]

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[dotnetshadow]

One possible workaround is to do this:

<ItemGroup>
	  <!-- extends watching group to include *.cshtml files -->
	  <Watch Include="**\*.cshtml" Exclude="node_modules\**\*;**\*.js.map;obj\**\*;bin\**\*" />
  </ItemGroup>

What is the impact of doing this?
Is RuntimeCompilation necessary? I'm converting from .net 5 to .net 6 so I'm wondering how the compilation works now?

I created an issue here, because I didn't see this ticket before
#39111