From 42beb1e91f8d12ec5388231cd24c4c197288c6e4 Mon Sep 17 00:00:00 2001
From: Daniel Han <danielhanchen@gmail.com>
Date: Thu, 16 Apr 2026 08:05:37 +0000
Subject: [PATCH] Append to User PATH by default, close $envKey in finally

Add-ToUserPath gains a -Position Append|Prepend parameter defaulting to
Append so installing unsloth no longer prepends the bundled venv Scripts
directory ahead of the user's existing python / pip on new shells. The
four current call sites (install.ps1 launcher, studio/setup.ps1 CMake,
nvcc, Python user Scripts) all take the Append default because each one
that needs in-session precedence already does an inline $env:Path prepend
independently. This matches rustup / cargo / nvm / pyenv / uv behavior.

Also wrap the script-top $envKey.GetValue in a try/finally so the
registry handle is released even if the read throws. Matches the pattern
already used for $backupKey five lines below.
---
 install.ps1      | 18 ++++++++++++++++--
 studio/setup.ps1 | 25 +++++++++++++++++++++----
 2 files changed, 37 insertions(+), 6 deletions(-)

diff --git a/install.ps1 b/install.ps1
index eb9b32f4ff..842ce90de9 100644
--- a/install.ps1
+++ b/install.ps1
@@ -134,9 +134,19 @@ function Install-UnslothStudio {
     # ── Helper: safely add a directory to the persistent User PATH ──
     # Uses direct registry access to preserve REG_EXPAND_SZ type
     # (avoids .NET SetEnvironmentVariable bug that converts to REG_SZ).
+    #
+    # Position: 'Append' (default) adds $Directory to the END of the persisted
+    # User PATH so existing user tools (e.g. system python, pip) keep taking
+    # precedence in new shells. This matches rustup/cargo/nvm/pyenv/uv behavior
+    # and avoids silently hijacking resolution of common executables. Pass
+    # 'Prepend' only when a caller truly needs the new entry to win over
+    # existing ones at registry scope. In-session precedence should be handled
+    # by an inline $env:Path = "$Dir;$env:Path" prepend instead.
     function Add-ToUserPath {
         param(
-            [Parameter(Mandatory = $true)][string]$Directory
+            [Parameter(Mandatory = $true)][string]$Directory,
+            [ValidateSet('Append','Prepend')]
+            [string]$Position = 'Append'
         )
         try {
             $regKey = [Microsoft.Win32.Registry]::CurrentUser.CreateSubKey('Environment')
@@ -171,7 +181,11 @@ function Install-UnslothStudio {
                 if (-not $rawPath) {
                     Write-Host "[WARN] User PATH is empty — initializing with $Directory" -ForegroundColor Yellow
                 }
-                $newPath = if ($rawPath) { "$Directory;$rawPath" } else { $Directory }
+                $newPath = if ($rawPath) {
+                    if ($Position -eq 'Prepend') { "$Directory;$rawPath" } else { "$rawPath;$Directory" }
+                } else {
+                    $Directory
+                }
                 $regKey.SetValue('Path', $newPath, [Microsoft.Win32.RegistryValueKind]::ExpandString)
                 # Broadcast WM_SETTINGCHANGE so other processes pick up the change
                 try {
diff --git a/studio/setup.ps1 b/studio/setup.ps1
index 052bfc8f83..173f97b8f0 100644
--- a/studio/setup.ps1
+++ b/studio/setup.ps1
@@ -104,9 +104,19 @@ function Refresh-Environment {
 # ── Helper: safely add a directory to the persistent User PATH ──
 # Uses direct registry access to preserve REG_EXPAND_SZ type
 # (avoids .NET SetEnvironmentVariable bug that converts to REG_SZ).
+#
+# Position: 'Append' (default) adds $Directory to the END of the persisted
+# User PATH so existing user tools (e.g. system python, pip) keep taking
+# precedence in new shells. This matches rustup/cargo/nvm/pyenv/uv behavior
+# and avoids silently hijacking resolution of common executables. Pass
+# 'Prepend' only when a caller truly needs the new entry to win over
+# existing ones at registry scope. In-session precedence should be handled
+# by an inline $env:Path = "$Dir;$env:Path" prepend instead.
 function Add-ToUserPath {
     param(
-        [Parameter(Mandatory = $true)][string]$Directory
+        [Parameter(Mandatory = $true)][string]$Directory,
+        [ValidateSet('Append','Prepend')]
+        [string]$Position = 'Append'
     )
     try {
         $regKey = [Microsoft.Win32.Registry]::CurrentUser.CreateSubKey('Environment')
@@ -143,7 +153,11 @@ function Add-ToUserPath {
             if (-not $rawPath) {
                 Write-Host "[WARN] User PATH is empty — initializing with $Directory" -ForegroundColor Yellow
             }
-            $newPath = if ($rawPath) { "$Directory;$rawPath" } else { $Directory }
+            $newPath = if ($rawPath) {
+                if ($Position -eq 'Prepend') { "$Directory;$rawPath" } else { "$rawPath;$Directory" }
+            } else {
+                $Directory
+            }
             $regKey.SetValue('Path', $newPath, [Microsoft.Win32.RegistryValueKind]::ExpandString)
             # Broadcast WM_SETTINGCHANGE so other processes pick up the change
             try {
@@ -584,8 +598,11 @@ if ($script:StudioVtOk -and -not $env:NO_COLOR) {
 try {
     $envKey = [Microsoft.Win32.Registry]::CurrentUser.OpenSubKey('Environment', $false)
     if ($envKey) {
-        $rawPath = $envKey.GetValue('Path', '', [Microsoft.Win32.RegistryValueOptions]::DoNotExpandEnvironmentNames)
-        $envKey.Close()
+        try {
+            $rawPath = $envKey.GetValue('Path', '', [Microsoft.Win32.RegistryValueOptions]::DoNotExpandEnvironmentNames)
+        } finally {
+            $envKey.Close()
+        }
         if ($rawPath) {
             $backupKey = [Microsoft.Win32.Registry]::CurrentUser.CreateSubKey('Software\Unsloth')
             try {