PR Summary

Fixes Get-Culture -ListAvailable:$false and Get-Location -Stack:$false, which incorrectly execute the switch-true code path when the switch value is explicitly $false.

The Bug

When -ListAvailable:$false or -Stack:$false is passed, PowerShell's parameter binder selects the corresponding ParameterSetName, but the cmdlet code branches on the set name without checking the actual switch value.

flowchart TD
    A["-ListAvailable:$false"] --> B["Binder selects\nListAvailableParameterSet"]
    B --> C{"Branches on\nset name only"}
    C -->|"Before · bug"| D["Dumps all 800 cultures ❌"]
    C -->|"After · fix"| E{"if ListAvailable"}
    E -->|true| F["List all cultures"]
    E -->|false| G["Return current culture ✓"]

The Fix

Wrap the switch-path code in if (SwitchParam) with an else fallback to default behavior:

  case ListAvailableParameterSet:
-     foreach (var ci in CultureInfo.GetCultures(CultureTypes.AllCultures))
-         WriteObject(ci);
+     if (ListAvailable)
+     {
+         foreach (var ci in CultureInfo.GetCultures(CultureTypes.AllCultures))
+             WriteObject(ci);
+     }
+     else
+     {
+         WriteObject(Host.CurrentCulture);
+     }
      break;

What Changed

Tests

• Get-Culture: 12/12 Pester tests pass (11 existing + 1 new)
• Get-Location: 2/2 pass (1 existing + 1 new -Stack:$false)

PR Context

This is part of the ongoing -Switch:$false cleanup tracked in #25242. Nine sibling PRs using the identical fix pattern have already been reviewed and merged. Also open: #26551 covering ConvertTo-Csv / Export-Csv.

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge. If this PR is a work in progress, please open this as a Draft Pull Request and mark it as Ready to Review when it is ready to merge.
• Breaking changes
  • None
• User-facing changes
  • Not Applicable
• Testing - New and feature
  • Make sure you've added a new test if existing tests do not effectively test the code changed