Razor runtime compilation fails for duplicate types using extern aliases.

[malylemire1]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Runtime compilation ignore the project references, assembly references or package references aliases.
I get a type exists in both assemblies error.

Expected Behavior

Aliases should be supported.

Steps To Reproduce

Create two class library projects with the same type name and namespace. Import one and the other in an asp.core project. Use an alias for one of them. Use the type without alias in a razor view and enable runtime compilation.

Exceptions (if any)

Type exists in both assemblies exception.

.NET Version

dotnet --6.0

Anything else?

No response

[malylemire1]

The problem seems to be here :

aspnetcore/src/Mvc/Mvc.Razor.RuntimeCompilation/src/RazorReferenceManager.cs

Line 80 in 5974b48

return assemblyMetadata.GetReference(filePath: path);

The GetReference should use the overload with aliases.

The problem is that aliases does not seems to be stored in the DependencyContext used here :

aspnetcore/src/Mvc/Mvc.Razor.RuntimeCompilation/src/AssemblyPartExtensions.cs

Line 29 in 5974b48

return dependencyContext.CompileLibraries.SelectMany(library => library.ResolveReferencePaths());

[javiercn]

@malylemire1 thanks for contacting us and for the detailed report.

Since this relies on the information being available in the dependency context, I'm going to move this to the backlog for future consideration, as it is currently blocked.

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[eerhardt]

I was unaware that we are still doing runtime compilation in razor. I thought it uses a source generator at build time.
What are the scenarios for doing runtime compilation in the latest ASP.NET?

[malylemire1]

For now we use it instead of hot reload because hot reload requires a rebuild witch is really slow on a 100+ projects solution. It's not a viable solution for simply updating some static text in a view at development time.

[javiercn]

@malylemire1 our recommended solution for development time is hot reload. Is there a reason why that doesn't work for your scenario?

[javiercn]

@eerhardt ASP.NET has shipped support for runtime compilation of Razor views I believe back to the ASP.NET MVC times. It is not until .NET 6.0 we moved to source generators for build time compilation.

Runtime compilation was used at development time before hot reload existed and some people use it in production scenarios to compile view updates on the fly.