Environment.GetCommandLineArgs()[0] points to non-existing file in single-file apps

[jkotas]

Repro:

using System;

class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine(Environment.GetCommandLineArgs()[0]);
    }
}

1. dotnet publish -r win-x64 --self-contained=false /p:PublishSingleFile=true
2. bin\Debug\net5.0\win-x64\publish\zzz.exe

Actual result:
c:\test\bin\Debug\net5.0\win-x64\publish\zzz.dll

Expected result:
path to file that physically exists on disk

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[am11]

Also, typeof(Program).Assembly.Location and .CodeBase return same absolute path to the non-existent zzz.dll.

[jkotas]

Related: #11305

[agocke]

@sbomer Could you take a look at this?

I'm actually not clear on what this should return. I think the user would expect the path to the single-file app, but if we don't return the path to the app host in the self-contained case it's also a little weird to do so now.

[mateoatr]

but if we don't return the path to the app host in the self-contained case it's also a little weird to do so now.

But self-contained apps will deploy a dll that the user can actually see.

[agocke]

@mateoatr Right, that's why I'm leaning towards the file path of the host. It just seems like the only thing we could reasonably point to.

[agocke]

Actually @mateoatr could you look at this instead? I @sbomer is looking at #36089

[swaroop-sridhar]

I'm actually not clear on what this should return. I think the user would expect the path to the single-file app, but if we don't return the path to the app host in the self-contained case it's also a little weird to do so now.

When an app is executed using an apphost (self-contained, framework-dependent, or single-file), its intuitive to expect the host-path as GetComandLineArgs[0]. I'm not sure why the path to the DLL is returned in place of the host path.

@jkotas Is this because we want to maintain consistency between runs that use dotnet host and apphost?
Do we know of any tooling that depends on the fact that GetComandLineArgs[0] is the path to the main assembly?

The other option is to return empty string as the assembly-path. The spec says "The first element in the array contains the file name of the executing program. If the file name is not available, the first element is equal to String.Empty."

I'm leaning towards the file path of the host. It just seems like the only thing we could reasonably point to.

I second.