Implement PowerShell import extension

Prerequisites

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Summary

I'm experiencing a weird issue while attempting to implement a PowerShell import extension. Firstly, I defined the extension manifest as such:

{
    "$schema": "https://aka.ms/dsc/schemas/v3/bundled/resource/manifest.json",
    "type": "Microsoft.DSC.Extension/PowerShell",
    "version": "0.1.0",
    "description": "Enable passing PowerShell v2 configuration document file directly to DSC, but requires pwsh executable to be available.",
    "import": {
        "fileExtensions": ["ps1"],
        "executable": "pwsh",
        "args": [
            "-NoLogo",
            "-NonInteractive",
            "-NoProfile",
            "-ExecutionPolicy",
            "Bypass",
            "-Command",
            {
                "fileArg": "Get-Content"
            },
            "$args | ./convert-resource.ps1 $args"
        ]
    }
}

Then, I created the convert-resource.ps1 as such:

[CmdletBinding()]
param (
    [Parameter(ValueFromPipeline = $true)]
    [string[]]$stringInput
)

begin {
    $lines = [System.Collections.Generic.List[string]]::new()

    $scriptModule = Import-Module "$PSScriptRoot/convertDscResource.psd1" -Force -PassThru
}

process {
    foreach ($line in $stringInput) {
        $lines.Add($line)  
    }
}

end {
    if ($lines.Count -ne 0) {
        $result = $scriptModule.invoke( { param($lines) Build-DscConfigDocument -Content $lines }, ($lines | Out-String) )

        return ($result | ConvertTo-Json -Depth 10 -Compress)
    }
}

The Build-DscConfigDocument generates a valid JSON string that can be ran by the engine. However, when I try to run it, somehow the process fails early on with the following error message:

Strangely enough, grabbing the exact same line that dsc.exe tries to execute from procmon, returns the JSON string:

Steps to reproduce

1. Clone the following repository: https://github.com/Gijsreyn/operation-methods.git
2. Check out the implement-powershell-import-extension
3. Build the project
4. Run the following example `dsc config get --file test.ps1

# test.ps1
configuration MyConfiguration {
        Import-DscResource -ModuleName PSDesiredStateConfiguration
        Node localhost
        {
            Environment CreatePathEnvironmentVariable
            {
                Name = 'TestPathEnvironmentVariable'
                Value = 'TestValue'
                Ensure = 'Present'
                Path = $true
                Target = @('Process')
            }
        }
    }

[!NOTE]
If you're wondering why I'm using the Get-Content; I have tried many combinations but couldn't figure one out properly. Open for suggestions!

Expected behavior

The configuration runs successfully

Actual behavior

See error in description

Error details

Environment data

Name                           Value
----                           -----
PSVersion                      7.5.2
PSEdition                      Core
GitCommitId                    7.5.2
OS                             Microsoft Windows 10.0.26100
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Version

dsc 3.2.0-preview.3

Visuals

No response