$MyInvocation.MyCommand.Path is $null in PowerGUI script editor

Question

When trying to debug my powershell script in the powerGUI script editor (2.0.0.1082) the $MyInvocation.MyCommand.Path is $null. It works when running the script via powershell. Running it in Powershell_ise.exe (on one of our servers) also works fine.

Have anyone else had the same problem or know what's wrong?

Here's my powershell version:

Name                           Value
----                           -----
CLRVersion                     2.0.50727.4927
BuildVersion                   6.1.7600.16385
PSVersion                      2.0
WSManStackVersion              2.0
PSCompatibleVersions           {1.0, 2.0}
SerializationVersion           1.1.0.1
PSRemotingProtocolVersion      2.1

Server version:

Name                           Value
----                           -----
CLRVersion                     2.0.50727.3082
BuildVersion                   6.0.6002.18111
PSVersion                      2.0
WSManStackVersion              2.0
PSCompatibleVersions           {1.0, 2.0}
SerializationVersion           1.1.0.1
PSRemotingProtocolVersion      2.1

Answer 1

The $MyInvocation.MyCommand object changes depending on the context of its execution. In this case, $MyInvocation.MyCommand.Path will only return something if called from the $script: scope, since that is the only valid scope to determine the directory from which the code was executed.

Therefore, the solution here would either be to use $script:MyInvocation.MyCommand.Path or $MyInvocation.ScriptName.

---

EDIT

Running this in the PowerShell ISE works as expected, as you get the same result if you run it in the PowerShell console:

function Main
{
    Write-Host ("MyCommand.Path from function: " + $MyInvocation.MyCommand.Path)
    Write-Host ("ScriptName from function: " + $MyInvocation.ScriptName)
}

Main

Write-Host ("MyCommand.Path from script scope: " + $MyInvocation.MyCommand.Path)
Write-Host ("ScriptName from script scope: " + $MyInvocation.ScriptName)

Output is:

MyCommand.Path from function: 
ScriptName from function: C:\temp\Test.ps1
MyCommand.Path from script scope: C:\temp\Test.ps1
ScriptName from script scope:

I haven't used PowerGUI, but if you don't get the same output, then its probably a bug.