Code OK on V5.1 does not run on V7.0.0RC2

Name                           Value
----                           -----
PSVersion                      7.0.0-rc.2
PSEdition                      Core
GitCommitId                    7.0.0-rc.2
OS                             Microsoft Windows 10.0.18363
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

The code in the attached script runs OK on V5 but generates the following error on V7:

MethodInvocationException: S:\PowerShellScripts\TestUserIngroup_1.ps1:5
Line |
   5 |  … t -Process {$_.GetType().InvokeMember('Name', 'GetProperty', $null, $ …
     |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     | Exception calling "InvokeMember" with "5" argument(s): "Unknown name. (0x80020006 (DISP_E_UNKNOWNNAME))"

The script:

$user = $env:USERNAME
$group = 'Users'
$groupObj = [ADSI]"WinNT://./$group,group"
$membersObj = @($groupObj.psbase.Invoke('Members'))
$members = ($membersObj | ForEach-Object -Process {$_.GetType().InvokeMember('Name', 'GetProperty', $null, $_, $null)})

If ($members -contains $user) 
{Write-Host -Object "$user exists in the group $group"}
Else 
{Write-Host -Object "$user does not exists in the group $group"}

TestUserIngroup_1.zip

[daxian-dbw]

Thanks @SeeminglyScience for analyzing the issue and pinpoint the cause ❤️

The ComEnumerator was introduced back in early .NET Core 2.0 preview period of time (#4553), because GetEnumerator() didn’t work on COM object even if the object can be cast to IEnumerable and .NET Core team said it was by design at the time (https://github.com/dotnet/runtime/issues/21690). With .NET Core 3.1, GetEnumerator() works on the COM objects that can be cast to IEnumerable 🎉

However, for the COM object that can be cast to IEnumerator, exception is thrown when calling MoveNext() on it. So we still need the ComEnumerator, but much simplified to just cover the case where the COM object implements COM.IEnumVARIANT interface.

PR was submitted: #11795

[iSazonov]

@SeeminglyScience Thanks for your investigations! I think we need to have more tests for COM interactions.