[AADMSGroup] Missing GroupType will cause Set-TargetResource to crash

[SebastianGoers]

Details of the scenario you tried and the problem that is occurring

Set-TargetResource will fail when the GroupType property of an AAD group is missing.

Verbose logs showing the problem

Setting configuration of Azure AD Groups
VERBOSE:[[AADMSGroup]xxx] Getting configuration of AzureAD Group
VERBOSE:[[AADMSGroup]xxx] Id was NOT specified
You cannot call a method on a null-valued expression.
At D:\... DscConfiguration.ps1:157 char:2
 +     $dscTestResults = Start-DSCConfiguration -UseExisting -wait
 +     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 + CategoryInfo          : InvalidOperation: (:) [], CimException
 + FullyQualifiedErrorId : InvokeMethodOnNull
 + PSComputerName        : localhost

Suggested solution to the issue

In Set-TargetResource GroupTypes is being evaluated, but the parameter is not mandatory. Thus, if the parameter is empty (aka missing in the config file), the script will crash.
Suggestion: Make GroupTypes a mandatory parameter for Set-TargetResource.

The line where the code crashes is:

@ $GroupTypes.Contains("Unified")

    if ($Ensure -eq 'Present' -and $GroupTypes.Contains("Unified") -and $MailEnabled -eq $false)
    {
        Write-Verbose -Message "Cannot set mailenabled to false if GroupTypes is set to Unified when creating group."
        throw "Cannot set mailenabled to false if GroupTypes is set to Unified when creating a group."
    }

The DSC configuration that is used to reproduce the issue (as detailed as possible)

The Group name "SEC_CLOUD_NOT_EXISITNG_GRP" has been used for demo purposes only.

AADMSGroup xxx
        {
            Description          = "SEC_CLOUD_NOT_EXISITNG_GRP";
            DisplayName       = "SEC_CLOUD_NOT_EXISITNG_GRP";
            Ensure                  = "Present";
            GlobalAdminAccount   = $Credsglobaladmin;
            Id                         = "";
            MailEnabled        = $false;
            MailNickname         = "SEC_CLOUD_NOT_EXISITNG_GRP";
            SecurityEnabled      = $true;
        }

The operating system the target node is running

Version of the DSC module that was used ('dev' if using current dev branch)

[NikCharlebois]

Update coming that will default group types to Unified if no implicit types are specified. This will prevent having to release a breaking change for this.