ValidateSet/Register-ArgumentCompleter/Enum completions does not work correctly

Issue Description

I am experiencing a problem with… completions failing for 2nd entry.

Notice that it works on 14th line, and then very same command fails on line 10th.

function Get-GPOZaurrPermissionSummary {
    [cmdletBinding()]
    param(
        [validateSet('AuthenticatedUsers', 'DomainComputers', 'Unknown', 'WellKnownAdministrative', 'NotWellKnown', 'NotWellKnownAdministrative', 'NotAdministrative', 'Administrative', 'All')][string[]] $Type = 'All',
        [validateSet('Allow', 'Deny', 'All')][string] $PermitType = 'All',
        [ValidateSet('GpoApply', 'GpoEdit', 'GpoCustom', 'GpoEditDeleteModifySecurity', 'GpoRead', 'GpoOwner', 'GpoCustomCreate', 'GpoCustomOwner')][string[]] $IncludePermissionType,
        [ValidateSet('GpoApply', 'GpoEdit', 'GpoCustom', 'GpoEditDeleteModifySecurity', 'GpoRead', 'GpoOwner', 'GpoCustomCreate', 'GpoCustomOwner')][string[]] $ExcludePermissionType,
        [Microsoft.GroupPolicy.GPPermissionType[]] $Test,

        [alias('ForestName')][string] $Forest,
        [string[]] $ExcludeDomains,
        [alias('Domain', 'Domains')][string[]] $IncludeDomains,
        [System.Collections.IDictionary] $ExtendedForestInformation,

        [string] $Separator
    )

I tried to replicate it to give you reproducible code but I just can’t. I’m experiencing it across all my modules and I can’t pinpoint it to what I’m doing wrong. It fails the same way for both [Microsoft.GroupPolicy.GPPermissionType[]] which is an enum, but also have the same issue with ValidateSet and Register-ArgumentCompleter that makes me want to cry 😃

Attached Logs

1601583262-5511c227-6bca-4824-9bad-6f29a894ed501601499246405.zip

Follow the instructions in the README about capturing and sending logs.

Environment Information

Visual Studio Code

Name	Version
Operating System	Windows_NT x64 10.0.19042
VSCode	1.49.2
PowerShell Extension Version	2020.9.0

PowerShell Information

Name	Value
PSVersion	5.1.19041.541
PSEdition	Desktop
PSCompatibleVersions	1.0 2.0 3.0 4.0 5.0 5.1.19041.541
BuildVersion	10.0.19041.541
CLRVersion	4.0.30319.42000
WSManStackVersion	3.0
PSRemotingProtocolVersion	2.3
SerializationVersion	1.1.0.1

Visual Studio Code Extensions

Visual Studio Code Extensions(Click to Expand)

Extension	Author	Version
better-toml	bungcip	0.3.2
csharp	ms-dotnettools	1.23.2
errorlens	usernamehw	3.2.2
github-linker	gimenete	0.2.3
gitlens	eamodio	10.2.2
line-endings	steditor	1.0.3
LogFileHighlighter	emilast	2.9.0
markdown-all-in-one	yzhang	3.3.0
material-icon-theme	PKief	4.3.0
open-in-browser	techer	2.0.0
powershell-preview	ms-vscode	2020.9.0
project-manager	alefragnani	11.3.0
rainbow-brackets	2gua	0.0.6
run-in-powershell	tobysmith568	1.1.0
swdc-vscode	softwaredotcom	2.3.12
vscode-markdownlint	DavidAnson	0.37.0
vscode-toggle-quotes	BriteSnow	0.3.3
vscode-wakatime	WakaTime	4.0.8
vscode-yaml	redhat	0.11.1
xml	DotJoshJohnson	2.5.1

[SeeminglyScience]

Also here’s an editor command you can use to test if TabExpansion2 gives the same result:

Microsoft.VSCode_profile.ps1

Register-EditorCommand -DisplayName 'Show Engine Completion Results' -Name EditorTabExpansion2 -ScriptBlock {
    param(
        [Microsoft.PowerShell.EditorServices.Extensions.EditorContext, Microsoft.PowerShell.EditorServices]
        $Context
    )
    end {
        function GetLineMap {
            [OutputType([int[]])]
            param([string] $text)
            end {
                $lineStartMap = [System.Collections.Generic.List[int]]::new(100)
                $lineStartMap.Add(0)
                for ($i = 0; $i -lt $text.Length; ++$i) {
                    $c = $text[$i];
    
                    if ($c -eq "`r"[0]) {
                        if (($i + 1) -lt $text.Length -and $text[$i + 1] -eq "`n"[0]) {
                            $i++;
                        }
    
                        $lineStartMap.Add($i + 1)
                    }
    
                    if ($c -eq "`n") {
                        $lineStartMap.Add($i + 1);
                    }
                }
    
                return ,$lineStartMap.ToArray()
            }
        }

        $fileContext = $Context.CurrentFile
        $scriptAst = $fileContext.Ast
        $scriptTokens = $fileContext.Tokens

        $scriptText = $scriptAst.Extent.Text
        $lineStartMap = GetLineMap $scriptText
        $offset = ($lineStartMap[$Context.CursorPosition.Line - 1] + $Context.CursorPosition.Column) - 1
        $newPosition = $scriptAst.Extent.StartScriptPosition.GetType().
            GetMethod(
                <# name: #> 'CloneWithNewOffset',
                <# bindingAttr: #> [System.Reflection.BindingFlags]'NonPublic, Public, Instance',
                <# binder: #> $null,
                <# types: #> [type[]][int],
                <# modifiers: #> $null).
            Invoke($scriptAst.Extent.StartScriptPosition, @($offset))

        $completionMatches = [System.Management.Automation.CommandCompletion]::
            CompleteInput($scriptAst, $scriptTokens, $newPosition, @{}).
            CompletionMatches

        if (-not $completionMatches) {
            Write-Host
            Write-Host 'CompleteInput returned no matches.'
            return
        }

        $completionMatches | Out-Host
    }
}

keybindings.json

    {
        "key": "ctrl+shift+space",
        "command": "PowerShell.InvokeRegisteredEditorCommand",
        "args": { "commandName": "EditorTabExpansion2" },
        "when": "editorTextFocus && editorLangId == 'powershell'",
    },

[PrzemyslawKlys]

COol 😄 I will be using the comma workaround in near future.