Could not scan /usr/local/share/dotnet/packs/Microsoft.AspNetCore.App.Ref/9.0.0/ref/net9.0/Microsoft.JSInterop.dll for Fable plugins

[forki]

Description

In .NET Aspire I always get: Could not scan /usr/local/share/dotnet/packs/Microsoft.AspNetCore.App.Ref/9.0.0/ref/net9.0/Microsoft.JSInterop.dll for Fable plugins

Is there anything I can do to work around that?

[MangelMaxime]

Hello,

Last time I worked on Fable plugin loading, I was not able to determine why we can't scan some of the assemblies for plugins. In theory, this warning is harmless I kept it because otherwise we had a silent error or the compiler would continue but with an unexpected result.

Does the associated Original error message contains some meaningful information?

Currently Fable scan all the assemblies for plugins, but if we could identity assemblies that we know for sure don't contains Fable plugins we could either not scan them or not report the errors.

For example, we know that any .NET Standard assemblies will never contains a Fable plugins. The question is how do we identify them?

[alfonsogarciacaro]

The list of core assemblies is just hardcoded XD

But we could do the same strategy as the project cracker to identify system packages... which is just checking if they start with "Microsoft.", "System.", etc.

Here:

Fable/src/Fable.Transforms/State.fs

Lines 32 to 40 in ffc6ee9

	if Compiler.CoreAssemblyNames.Contains(asmName) then
	coreAssemblies.Add(asmName, asm)
	else
	let scanForPlugins =
	try
	asm.Contents.Attributes
	|> Seq.exists (fun attr ->
	attr.AttributeType.TryFullName = Some "Fable.ScanForPluginsAttribute"
	)

[forki]

Could not scan /usr/local/share/dotnet/packs/Microsoft.AspNetCore.App.Ref/9.0.2/ref/net9.0/Microsoft.AspNetCore.Mvc.dll for Fable plugins, skipping this assembly. Original error: The exception has been reported. This internal exception should now be caught at an error recovery point on the stack. Original message: The type 'MetadataUpdateHandlerAttribute' is required here and is unavailable. You must add a reference to assembly 'System.Runtime.Loader, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.)

that's all I have as info.

[MangelMaxime]

@forki I think what Alfonso is saying is that we could decide that we don't scan assemblies starting with "Microsoft.", "System.", etc. because they probably will never have a Fable plugin in them.

I don't think anyone outside of Microsoft can releases package starting with these names.