Install-Boxstarter expands variables in PATH and PSModulePath, overwriting preexisting variables

[cmconti]

Install-Boxstarter will expand all variables in your PATH and PSModulePath, and then write back the expanded values, overwriting any unexpanded variables that existed in PATH/PSModulePath prior to Install-Boxstarter being called.

This is a very similar issue to chocolatey/choco#303 (plus the patch in chocolatey/choco#699)

before installing boxstarter:

PS C:\> (get-item 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Environment').GetValue('Path','','DoNotExpandEnvironmentNames')
%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;%SYSTEMROOT%\System32\OpenSSH\;C:\ProgramData\chocolatey\bin;
PS C:\> (get-item 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Environment').GetValue('PSModulePath','','DoNotExpandEnvironmentNames')
%ProgramFiles%\WindowsPowerShell\Modules;%SystemRoot%\system32\WindowsPowerShell\v1.0\Modules

after installing boxstarter (using: choco install -y boxstarter --params "nodesktopicon"):

PS C:\> (get-item 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Environment').GetValue('Path','','DoNotExpandEnvironmentNames')
C:\ProgramData\Boxstarter;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Windows\System32\OpenSSH\;C:\ProgramData\chocolatey\bin;
PS C:\> (get-item 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Environment').GetValue('PSModulePath','','DoNotExpandEnvironmentNames')
C:\ProgramData\Boxstarter;C:\Program Files\WindowsPowerShell\Modules;C:\Windows\system32\WindowsPowerShell\v1.0\Modules

I'm not in a position to fully test this myself (I have at least tested it on a fresh install of windows 10 1903), but I think this will address the issue:

function PersistBoxStarterPathToEnvironmentVariable($variableName, $boxstarterPath) {
    # Remove user scoped vars from previous releases
    $keyUser = (get-item 'HKCU:\').OpenSubKey('Environment', $true)
    $oldval = $keyUser.GetValue($variableName,'','DoNotExpandEnvironmentNames')
    if ($oldval) {
        $tmp = ($oldval.Split(';', [StringSplitOptions]::RemoveEmptyEntries) | Where-Object { !($_.ToLower() -match "\\boxstarter$")})
        $newval = $tmp -join ';'
    }
    elseif($variableName -eq "PSModulePath") {
        $newval = [environment]::getfolderpath("mydocuments")
        $newval +="\WindowsPowerShell\Modules"
    }
    $keyUser.SetValue($variableName,$newval,[Microsoft.Win32.RegistryValueKind]::ExpandString)

    $keyMachine = (get-item 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\').OpenSubKey('Environment', $true)
    $oldval = $keyMachine.GetValue($variableName,'','DoNotExpandEnvironmentNames')
    if ($oldval) {
        $tmp = ($oldval.Split(';', [StringSplitOptions]::RemoveEmptyEntries) | Where-Object { !($_.ToLower() -match "\\boxstarter$")})
        $tmp += $boxstarterPath
        $newval = $tmp -join ';'
    }
    elseif($variableName -eq "PSModulePath") {
        $newval = "$boxstarterPath;"
        $newval += "%ProgramFiles%\WindowsPowerShell\Modules"
    }
    else {
        $newval ="$boxstarterPath"
    }
    $keyMachine.SetValue($variableName,$newval,[Microsoft.Win32.RegistryValueKind]::ExpandString)

    $varValue = Get-Content env:\$variableName
    $varValue = "$boxstarterPath;$varValue"
    Set-Content env:\$variableName -value $varValue
}

2 notes:

1. The above code adds $boxstarterPath to the end of an existing path. I don't know if that is important or not
2. Question: if PSModulePath does not exist for the user (it doesn't on my fresh 1903 install), is there a reason to add [environment]::getfolderpath("mydocuments")+"\WindowsPowerShell\Modules" ?

[pauby]

I'll take a look at this soon. I think the function should be rewritten. To answer your questions:

1. This is just going to add $boxstarterPath (which is the new location of Boxstarter) onto the end of the PATH ;

2. If PSModulePath doesn't exist then we need to create it so the path to the modules have somewhere to sit. By default the user path for Windows PowerShell modules is in Documents\WindowsPowerShell\Modules.