Resolving the Studio Home directory is a recurring and complex logical check that is duplicated in multiple places in this script (here and at line 1813). Centralizing this logic into a single helper function improves maintainability and ensures consistency.

Additionally, there is a critical bug in the current tilde expansion logic: if $_prereqStudioHome is exactly "~", then $_prereqStudioHome.Substring(1) returns an empty string "". Passing an empty string as the ChildPath argument to Join-Path throws a terminating error in PowerShell 5.1: Join-Path : Cannot bind argument to parameter 'ChildPath' because it is an empty string. Since $ErrorActionPreference = "Stop" is set, this will crash the setup script.

Defining a helper function Get-StudioHome that handles the exact "~" case separately resolves both the duplication and the potential crash.

function Get-StudioHome {
    $homeDir = $null
    if (-not [string]::IsNullOrWhiteSpace($env:UNSLOTH_STUDIO_HOME)) {
        $homeDir = $env:UNSLOTH_STUDIO_HOME.Trim()
    } elseif (-not [string]::IsNullOrWhiteSpace($env:STUDIO_HOME)) {
        $homeDir = $env:STUDIO_HOME.Trim()
    } else {
        $homeDir = Join-Path $env:USERPROFILE ".unsloth\studio"
    }
    if ($homeDir -eq "~") {
        $homeDir = $env:USERPROFILE
    } elseif ($homeDir -like "~/*" -or $homeDir -like "~\*") {
        $homeDir = Join-Path $env:USERPROFILE $homeDir.Substring(1).TrimStart('/','\')
    }
    return $homeDir
}

$_prereqStudioHome = Get-StudioHome

The regular expression 'Python (3\.(11|12|13)(\.\d+)?)' can match incorrectly if the minor version starts with 11, 12, or 13 but has trailing digits (e.g., 3.110 or 3.120 in future releases). Adding a word boundary \b after the minor version ensures that only exact matches for 3.11, 3.12, or 3.13 are matched.

        if ($out -match 'Python (3\.(11|12|13)\b(\.\d+)?)') {