AI Generated PowerShell function to list argument completers and their associated script blocks

Get-ArgumentCompleters.ps1

function Get-ArgumentCompleters {
    <#
    .SYNOPSIS
    Lists all registered argument completers created with Register-ArgumentCompleter.
    
    .DESCRIPTION
    This function retrieves all custom argument completers registered in the current PowerShell session
    using Register-ArgumentCompleter and displays their script block contents.
    
    .PARAMETER ShowScriptBlock
    If specified, displays the full script block content in a readable format.
    
    .EXAMPLE
    Get-ArgumentCompleters
    Lists all registered argument completers.
    
    .EXAMPLE
    Get-ArgumentCompleters -ShowScriptBlock
    Lists all registered argument completers with full script block content.
    #>
    
    [CmdletBinding()]
    param(
        [switch]$ShowScriptBlock
    )
    
    try {
        $completers = @()
        
        # Access the internal ExecutionContext to get to the CommandDiscovery
        $contextField = $ExecutionContext.GetType().GetField('_context', [System.Reflection.BindingFlags]::NonPublic -bor [System.Reflection.BindingFlags]::Instance)
        if (-not $contextField) {
            throw "Could not access ExecutionContext._context field"
        }
        
        $internalContext = $contextField.GetValue($ExecutionContext)
        if (-not $internalContext) {
            throw "Could not get internal ExecutionContext"
        }
        
        # Get the AutomationEngine
        $engineField = $internalContext.GetType().GetField('<Engine>k__BackingField', [System.Reflection.BindingFlags]::NonPublic -bor [System.Reflection.BindingFlags]::Instance)
        if (-not $engineField) {
            throw "Could not access Engine field"
        }
        
        $automationEngine = $engineField.GetValue($internalContext)
        if (-not $automationEngine) {
            throw "Could not get AutomationEngine"
        }
        
        # Get the CommandDiscovery
        $commandDiscoveryField = $automationEngine.GetType().GetField('<CommandDiscovery>k__BackingField', [System.Reflection.BindingFlags]::NonPublic -bor [System.Reflection.BindingFlags]::Instance)
        if (-not $commandDiscoveryField) {
            throw "Could not access CommandDiscovery field"
        }
        
        $commandDiscovery = $commandDiscoveryField.GetValue($automationEngine)
        if (-not $commandDiscovery) {
            throw "Could not get CommandDiscovery"
        }
        
        # Look for argument completer storage in CommandDiscovery
        $discoveryFields = $commandDiscovery.GetType().GetFields([System.Reflection.BindingFlags]::Instance -bor [System.Reflection.BindingFlags]::NonPublic -bor [System.Reflection.BindingFlags]::Public)
        
        foreach ($field in $discoveryFields) {
            try {
                $value = $field.GetValue($commandDiscovery)
                if ($value -ne $null -and $value.GetType().Name -like "*Dictionary*") {
                    # Check if this dictionary contains script blocks (likely completers)
                    foreach ($kvp in $value.GetEnumerator()) {
                        if ($kvp.Value -and $kvp.Value.GetType().Name -eq "ScriptBlock") {
                            $completers += [PSCustomObject]@{
                                CommandName = $kvp.Key
                                CompleterSource = "CommandDiscovery.$($field.Name)"
                                ScriptBlock = if ($ShowScriptBlock) { $kvp.Value.ToString() } else { $kvp.Value.ToString().Substring(0, [Math]::Min(100, $kvp.Value.ToString().Length)) + "..." }
                                FullScriptBlock = $kvp.Value
                            }
                        }
                    }
                }
            }
            catch {
                # Ignore fields we can't access
                continue
            }
        }
        
        # If we didn't find completers in CommandDiscovery, try looking in the execution context itself
        if ($completers.Count -eq 0) {
            $contextFields = $internalContext.GetType().GetFields([System.Reflection.BindingFlags]::Instance -bor [System.Reflection.BindingFlags]::NonPublic -bor [System.Reflection.BindingFlags]::Public)
            
            foreach ($field in $contextFields) {
                try {
                    $value = $field.GetValue($internalContext)
                    if ($value -ne $null -and $value.GetType().Name -like "*Dictionary*") {
                        foreach ($kvp in $value.GetEnumerator()) {
                            if ($kvp.Value -and $kvp.Value.GetType().Name -eq "ScriptBlock") {
                                $completers += [PSCustomObject]@{
                                    CommandName = $kvp.Key
                                    CompleterSource = "ExecutionContext.$($field.Name)"
                                    ScriptBlock = if ($ShowScriptBlock) { $kvp.Value.ToString() } else { $kvp.Value.ToString().Substring(0, [Math]::Min(100, $kvp.Value.ToString().Length)) + "..." }
                                    FullScriptBlock = $kvp.Value
                                }
                            }
                        }
                    }
                }
                catch {
                    continue
                }
            }
        }
        
        # Return results
        if ($completers.Count -gt 0) {
            $result = $completers | Sort-Object CommandName
            
            if ($ShowScriptBlock) {
                foreach ($completer in $result) {
                    Write-Host "`n=== $($completer.CommandName) ===" -ForegroundColor Green
                    Write-Host "Source: $($completer.CompleterSource)" -ForegroundColor Yellow
                    Write-Host "Script Block:" -ForegroundColor Cyan
                    Write-Host $completer.FullScriptBlock.ToString() -ForegroundColor White
                    Write-Host ("-" * 50) -ForegroundColor Gray
                }
            } else {
                $result | Select-Object CommandName, CompleterSource, ScriptBlock
            }
        } else {
            Write-Warning "No argument completers found in the current session."
            Write-Host "`nThis could be because:" -ForegroundColor Yellow
            Write-Host "  1. No completers have been registered with Register-ArgumentCompleter" -ForegroundColor Cyan
            Write-Host "  2. The internal storage mechanism has changed in this PowerShell version" -ForegroundColor Cyan
            Write-Host "  3. Completers are stored in a location not yet discovered by this function" -ForegroundColor Cyan
            Write-Host "`nTo register a new completer, use:" -ForegroundColor Yellow
            Write-Host "Register-ArgumentCompleter -CommandName 'YourCommand' -ScriptBlock { param(`$commandName, `$parameterName, `$wordToComplete, `$commandAst, `$fakeBoundParameter) }" -ForegroundColor Cyan
        }
    }
    catch {
        Write-Error "Failed to retrieve argument completers: $($_.Exception.Message)"
        Write-Host "`nThis error suggests the internal PowerShell structure may have changed." -ForegroundColor Yellow
        Write-Host "Please report this issue with your PowerShell version: $($PSVersionTable.PSVersion)" -ForegroundColor Cyan
    }
}

# Remove the Export-ModuleMember since this is a script, not a module