(GH-375) HKCU may not have Environment

When attempting to expand or work with `HKCU:\Environment`, that can
error due to not having an existing `Environment` key in HKCU. This can
occur in certain Windows Server versions, such as Server Core which
doesn't have the key. This can also happen in other situations as well.

- In `Get-EnvironmentVariableNames`, when expanding from
   `HKCU:\Environment` and it fails, silently continue.
- When attempting to remove variables at User scope for
   Get-ToolsLocation, fail those silently.
- If you can't set the Get-ToolsLocation value for User scope, attempt
   Machine scope instead.
- With `Install-ChocolateyEnvironmentVariable`, if the attempt to set
   to User scope fails and the user is an administrator, attempt to set
   it with Machine scope. Otherwise fail.
- In `Get-EnvironmentVariable`, if the registry key is null, do not
   attempt to grab a value or close it.

src/chocolatey.resources/helpers/functions/Get-EnvironmentVariable.ps1

@@ -81,11 +81,16 @@ param(
 
   try {
     #Write-Verbose "Getting environment variable $Name"
-    $environmentVariableValue = $win32RegistryKey.GetValue($Name, [string]::Empty, $registryValueOptions)
+    if ($win32RegistryKey -ne $null) {
+      # Some versions of Windows do not have HKCU:\Environment
+      $environmentVariableValue = $win32RegistryKey.GetValue($Name, [string]::Empty, $registryValueOptions)
+    }
   } catch {
     Write-Debug "Unable to retrieve the $Name environment variable. Details: $_"
   } finally {
-    $win32RegistryKey.Close()
+    if ($win32RegistryKey -ne $null) {
+      $win32RegistryKey.Close()
+    }
   }
 
   if ($environmentVariableValue -eq $null -or $environmentVariableValue -eq '') {

src/chocolatey.resources/helpers/functions/Get-EnvironmentVariableNames.ps1

@@ -45,8 +45,9 @@ Get-EnvironmentVariable
 Set-EnvironmentVariable
 #>
 
+  # HKCU:\Environment may not exist in all Windows OSes (such as Server Core).
   switch ($Scope) {
-    'User' { Get-Item 'HKCU:\Environment' | Select-Object -ExpandProperty Property }
+    'User' { Get-Item 'HKCU:\Environment' -ErrorAction SilentlyContinue | Select-Object -ExpandProperty Property }
     'Machine' { Get-Item 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager\Environment' | Select-Object -ExpandProperty Property }
     'Process' { Get-ChildItem Env:\ | Select-Object -ExpandProperty Key }
     default { throw "Unsupported environment scope: $Scope" }

src/chocolatey.resources/helpers/functions/Get-ToolsLocation.ps1

@@ -62,21 +62,30 @@ None
         if ($binRoot -eq $null) {
           $binRoot = $olderRoot
         }
-        Set-EnvironmentVariable -Name "chocolatey_bin_root" -Value '' -Scope User
+        Set-EnvironmentVariable -Name "chocolatey_bin_root" -Value '' -Scope User -ErrorAction SilentlyContinue
       }
 
       $toolsLocation = $binRoot
-      Set-EnvironmentVariable -Name "ChocolateyBinRoot" -Value '' -Scope User
+      Set-EnvironmentVariable -Name "ChocolateyBinRoot" -Value '' -Scope User -ErrorAction SilentlyContinue
     }
   }
 
   # Add a drive letter if one doesn't exist
   if (-not($toolsLocation -imatch "^\w:")) {
-    $toolsLocation = join-path $env:systemdrive $toolsLocation
+    $toolsLocation = Join-Path $env:systemdrive $toolsLocation
   }
 
   if (-not($env:ChocolateyToolsLocation -eq $toolsLocation)) {
-    Set-EnvironmentVariable -Name "ChocolateyToolsLocation" -Value $toolsLocation -Scope User
+    try {
+      Set-EnvironmentVariable -Name "ChocolateyToolsLocation" -Value $toolsLocation -Scope User
+    } catch {
+      if (Test-ProcessAdminRights) {
+        # sometimes User scope may not exist (such as with core)
+        Set-EnvironmentVariable -Name "ChocolateyToolsLocation" -Value $toolsLocation -Scope Machine
+      } else {
+        throw $_.Exception
+      }
+    }
   }
 
   return $toolsLocation

src/chocolatey.resources/helpers/functions/Install-ChocolateyEnvironmentVariable.ps1

@@ -102,7 +102,16 @@ param(
       Start-ChocolateyProcessAsAdmin "$psArgs"
     }
   } else {
-    Set-EnvironmentVariable -Name $variableName -Value $variableValue -Scope $variableType
+    try {
+      Set-EnvironmentVariable -Name $variableName -Value $variableValue -Scope $variableType
+    } catch {
+      if (Test-ProcessAdminRights) {
+        # HKCU:\Environment may not exist, which happens sometimes with Server Core
+        Set-EnvironmentVariable -Name $variableName -Value $variableValue -Scope Machine
+      } else {
+        throw $_.Exception
+      }
+    }
   }
 
   Set-Content env:\$variableName $variableValue