Fix using [ScriptBlock]::Create with InModuleScope.

[sethvs]

1. General summary of the pull request

We use ScriptBlock with InModuleScope.

Now we can use it like this:

Describe "{}" {
    $ScriptBlock = {Write-Output -InputObject 'This is a ScriptBlock'}
    Import-Module -Name PowerShellGet
    InModuleScope -ModuleName PowerShellGet -ScriptBlock $ScriptBlock
}

the result is:

Describing {}

But if we need to construct ScriptBlock dynamicly by using [ScriptBlock]::Create method

Describe "[ScriptBlock]::Create" {
    $ScriptBlockText = "Write-Output -InputObject 'This is a ScriptBlock'"
    $ScriptBlock = [ScriptBlock]::Create($ScriptBlockText)
    Import-Module -Name PowerShellGet
    InModuleScope -ModuleName PowerShellGet -ScriptBlock $ScriptBlock
}

the result will be:

Describing [ScriptBlock]::Create
  [-] Error occurred in Describe block 49ms
    ParameterBindingValidationException: Cannot bind argument to parameter 'SessionStateInternal' because it is null.

This is because, when InModuleScope function gets $originalScriptBlockScope of the ScriptBlock

Pester/Functions/InModuleScope.ps1

Line 74 in 5a53c46

$originalScriptBlockScope = Get-ScriptBlockScope -ScriptBlock $ScriptBlock

the result will be $null.

It seems, that ScriptBlock created with Create method doesn't have SessionStateInternal property.
For example this code returns null:

$ScriptBlockText = "Write-Output -InputObject 'This is a ScriptBlock'"
$ScriptBlock = [ScriptBlock]::Create($ScriptBlockText)
$flags = [System.Reflection.BindingFlags]'Instance,NonPublic'
[scriptblock].GetProperty('SessionStateInternal', $flags).GetValue($ScriptBlock, $null)

So, when InModuleScope function tries to return the $originalScriptBlockScope to the ScriptBlock

Pester/Functions/InModuleScope.ps1

Line 90 in 5a53c46

Set-ScriptBlockScope -ScriptBlock $ScriptBlock -SessionStateInternal $originalScriptBlockScope

the Set-ScriptBlockScope throws an error, because -SessionStateInternal parameter cannot be null.

This PS allows -SessionStateInternal parameter to accept null, so that ScriptBlock will have its original SessionStateInternal back, even if it is $null.

[nohwnd]

@sethvs nice catch. Could you add tests for it as well please? 🙂

[sethvs]

Sorry for delay :)

[nohwnd]

I don't see any need to mix the two tests cases together. Could you split them to Can execute bound ScriptBlock inside the module scope ({} makes scriptblock bound to the current session) and Can execute unbound ScriptBlock in module scope please? :)

[sethvs]

Is it OK with Should swallow test output without -PassThru test in PowerShell v2?

[nohwnd]

@sethvs sorry I don't get what you are asking. Could you rephrase please?

[sethvs]

Publish Status to GitHub (Pester) check is failed on test with name Should swallow test output without -PassThru when it was run on PowerShell v2.
Just want to say, I haven't touched this test :)

[nohwnd]

@sethvs Now I get it. There is some ongoing problem with the build server, that makes some of the tests fail, I am
not sure if it's the problem of the test or the server. Plus it's really hard to investigate when the server waits 3 hours to run the build. I tried running it again to see if the error stays the same.

[nohwnd]

@sethvs Merged, thanks ! 👍