Avoid benign GAC warnings logged by install/uninstall

[pjanotti]

Running the PowerShell install/uninstall ends up logging warning events to the Windows Event Logger that are benign and not actionable by the user:

This issue is a follow-up to #1906

[pellared]

Do you have any preference on how to implement it?
I see two possibilities:

1. Use https://learn.microsoft.com/en-us/dotnet/standard/assembly/identify#using-the-pereader-class.

   Pros:

   • should not require a lot of maintenance in future

   Cons:

   • would probably not cover netstandard.dll. I guess this one would need special handling.
   • Would require using https://www.nuget.org/packages/System.Reflection.Metadata/ inside the powershell module

2. Have a "exclude list" which would currently be the 3 assemblies.

   Pros:

   • no dependencies and possibly best performance

   Cons:

   • would require more maintaince (updating the exclude list)

We could consider also writing a PowerShell unit test to check if after using the module there are no new errors or warnings in the Windows Event Log.

[rajkumar-rangaraj]

It's worth exploring option 1, at a different it could help in different places too.

[pellared]

I spend a few hours trying the option 1, but there are too many obstacles to make it worth in my opinion. Example problems:

• We would have to Register-PackageSource and later remove it.
• We would have to download all needed packages (together with dependencies) and then remove them at the end. See: Installing System.Net.Http using Install-Package fails with "Dependency loop detected for package"  OneGet/oneget#475
• For some reasons I have failed to have a working Install-Package which worked fine and downloaded exactly what I wanted.

Notable article: https://endjin.com/blog/2020/12/how-to-consume-a-nuget-package-in-powershell Maybe someone else would have more luck...

Ported C# snippet to PowerShell (not tested):

function Test-Assembly([string] $Path) {
    try {
        $fs = [System.IO.FileStream]::new($Path, [System.IO.FileMode.Open], [System.IO.FileAccess.Read], [System.IO.FileShare.ReadWrite])

        # Try to read CLI metadata from the PE file.
        $peReader = [System.Reflection.PortableExecutable.PEReader]::new($fs)

        if (-not $peReader.HasMetadata) {
            return $false # File does not have CLI metadata.
        }

        # Check that file has an assembly manifest.
        $reader = $peReader.GetMetadataReader()
        return $reader.IsAssembly
    }
    finally {
        if ($null -ne $fs) {
            $fs.Dispose()
        }
        if ($null -ne $peReader) {
            $fs.Dispose()
        }
    }
}