PR Summary

Use CommandInfo within Command.CreateCommandProcessor() if available.

PR Context

During testing of PowerShell.GetSteppablePipeline(), I found that I could not reference internal-scoped cmdlets of my module despite providing a proper CmdletInfo object to PowerShell.AddCommand(). Further review found that Command.CreateCommandProcessor() is eschewing the CommandInfo object it has a hold of for the text representing the command instead.

This PR tests whether Command.CommandInfo is null and if not, uses the CommandInfo overload of CommandDiscovery.LookupCommandProcessor() instead, which not only addresses this problem, but also addresses what I consider to be a security concern where I might be explicitly using a CommandInfo object of a trusted command to not be subject to command/function re-definition.

Test function for validation of this PR before/after:

function Get-CommandSteppable {
    [CmdletBinding()]
    param
    (
    )

    begin
    {
        $pwsh = [System.Management.Automation.PowerShell]::Create([System.Management.Automation.RunspaceMode]::CurrentRunspace)
        try
        {
            $steppablePipeline = $pwsh.AddCommand([System.Management.Automation.CmdletInfo]::new("Get-CommandWithUnresolvableName", [Microsoft.PowerShell.Commands.GetCommandCommand])).GetSteppablePipeline()
        }
        catch
        {
            $PSCmdlet.ThrowTerminatingError($_)
        }
        finally
        {
            $pwsh.Dispose();
            Remove-Variable -Name pwsh
        }
        $steppablePipeline.Begin($PSCmdlet)
    }

    process
    {
        $null = $steppablePipeline.Process()
    }

    end
    {
        $null = $steppablePipeline.End()
        $steppablePipeline.Dispose()
    }
}

Before:

PS C:\Repos\PowerShell> Get-CommandSteppable
Get-CommandSteppable: Exception calling "GetSteppablePipeline" with "0" argument(s): "The term 'Get-CommandWithUnresolvableName' is not recognized as a name of a cmdlet, function, script file, or executable program.
Check the spelling of the name, or if a path was included, verify that the path is correct and try again."
PS C:\Repos\PowerShell>

After:

PS C:\Repos\PowerShell> Get-CommandSteppable

CommandType     Name                                               Version    Source
-----------     ----                                               -------    ------
Alias           Add-AppPackage ->                                  2.0.1.0    Appx
Alias           Add-AppPackageVolume ->                            2.0.1.0    Appx
Alias           Add-AppProvisionedPackage ->                       3.0        Dism
Alias           Add-AssertionOperator ->                           5.7.1      Pester
Alias           Add-MsixPackage ->                                 2.0.1.0    Appx
Alias           Add-MsixPackageVolume ->                           2.0.1.0    Appx
...

PS C:\Repos\PowerShell>

This is also my first PR to the project so if I've done anything wrong, just let me know and I'll get it fixed up.

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge. If this PR is a work in progress, please open this as a Draft Pull Request and mark it as Ready to Review when it is ready to merge.
• Breaking changes
  • None
  • OR
  • Experimental feature(s) needed
    • Experimental feature name(s):
• User-facing changes
  • Not Applicable
  • OR
  • Documentation needed
    • Issue filed:
• Testing - New and feature
  • N/A or can only be tested interactively
  • OR
  • Make sure you've added a new test if existing tests do not effectively test the code changed