How to get Powershell to recognise pscx modules? - powershell

Question

I installed powershell community extensions because I want to use Show-Tree for this code.
# Log project state
# Assumes CWD is the project file
$Tree = Show-Tree -ShowProperty -ShowLeaf | Where-Object {$_ -inotmatch '^.*Property.*' -or $_ -match '^.*LastWriteTime\s.*'}
$i = 0
$culture = [Globalization.CultureInfo]::InvariantCulture
foreach($entry in $Tree){
if($entry -notmatch '^.*Property.*'){
$d = "{0:hh}:{0:mm}:{0:ss}" -f ([DateTime]::Parse($($Tree[$i+1] -replace '^.+=\s(.+)','$1'), $culture))
$Tree[$i] = "$d`t$entry"
}
$i++
}
$Tree = $Tree | Where-Object {$_ -inotmatch '^.*Property.*'}
foreach($s in $Tree){Write-Output $s}
This works OK in a PS debug session in VS Code but when I try to use it in MSBuild or with the powershell command prompt, it complains that it can't find the extension module...
Show-Tree : The term 'Show-Tree' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again. At C:\Users\Admin\Documents\GitHub\powershell-scripts\ProjectSnapShot.ps1:6 char:9
+ $Tree = Show-Tree -ShowProperty -ShowLeaf | Where-Object {$_ -inotmat ...
+ ~~~~~~~~~
+ CategoryInfo : ObjectNotFound: (Show-Tree:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException
I checked the PSModulePath env variable and it is pointing to two valid loctions, one the std modules and the other pscx modules...
According to the docs, this should mean the module is loaded automatically.
Generally speaking, you can determine where you should install your
module by using one of the paths stored in the $ENV:PSModulePath
variable. Using one of these paths means that PowerShell can
automatically find and load your module when a user makes a call to it
in their code. If you store your module somewhere else, you can
explicitly let PowerShell know by passing in the location of your
module as a parameter when you call Install-Module.
How can I get this to work from the PS command prompt and when called from MSBuild?

Answer 1

Assuming you're having this problem when running the above code as a script, there are a number of things you can do, for example:
If you're only worried about this script running on your machine, you could pass Import-Module the explicit .psm1 path of the module file containing the function Show-Tree before you assign the $Tree variable.
If you're looking for more portability, you could copy the code defining the function Show-Tree from the .psm1 module file into this script, again, before you assign the $Tree variable.
If you're looking more to figure out why this is happening, here is the section on inheritance from the PowerShell help file about_Scopes:
Inheritance
A child scope does not inherit the variables, aliases, and functions from the parent scope. Unless an item is private, the child scope can view the items in the parent scope. And, it can change the items by explicitly specifying the parent scope, but the items are not part of the child scope.
However, a child scope is created with a set of items. Typically, it includes all the aliases that have the AllScope option. This option is discussed later in this topic. It includes all the variables that have the AllScope option, plus some variables that can be used to customize the scope, such as MaximumFunctionCount.

Answer 2

This problem was resolved after re-booting my computer. There were some other strange instabilities (new errors being thrown despite nothing having changed) that also disappeared after the re-boot.

Answer 3

I observed similar behaviour as well. Even if the GUI shows that PSMODULEPATH is ok, running processes (like explorer.exe) do not automatically pick up changes to the environment. Usually Log-Off/-On or a reboot helps.
Background:
When a process starts, the current environment is copied "into" the process. If a process starts another process, like if you start a program using Windows Explorer, the new child process gets a copy of the parent processes environment. Changes to the user or system environment variables are therefore not picked up by running processes unless the process explicitly listens to WM_SETTINGSCHANGED window message and reacts accordingly. From my experience not many processes do this correctly.