fix: replace setx with reg add to avoid 1024-char PATH truncation (#101)

- Use reg add instead of setx to bypass Windows 1024-character limit
- Add safety check for quotes/exclamation marks in PATH to prevent injection
- Preserve stderr output for better error diagnostics
- Update documentation with warnings about cmd PATH duplication
- Add test script for PATH update validation

Generated with SWE-Agent.ai

Co-Authored-By: SWE-Agent.ai <noreply@swe-agent.ai>

README.md

@@ -346,8 +346,10 @@ $Env:PATH = "$HOME\bin;$Env:PATH"
 ```
 
 ```batch
-REM cmd.exe - persistent for current user
+REM cmd.exe - persistent for current user (use PowerShell method above instead)
-setx PATH "%USERPROFILE%\bin;%PATH%"
+REM WARNING: This expands %PATH% which includes system PATH, causing duplication
+REM Note: Using reg add instead of setx to avoid 1024-character truncation limit
+reg add "HKCU\Environment" /v Path /t REG_EXPAND_SZ /d "%USERPROFILE%\bin;%PATH%" /f
 ```
 
 ---

README_CN.md

@@ -282,8 +282,10 @@ $Env:PATH = "$HOME\bin;$Env:PATH"
 ```
 
 ```batch
-REM cmd.exe - 永久添加（当前用户）
+REM cmd.exe - 永久添加（当前用户）（建议使用上面的 PowerShell 方法）
-setx PATH "%USERPROFILE%\bin;%PATH%"
+REM 警告：此命令会展开 %PATH% 包含系统 PATH，导致重复
+REM 注意：使用 reg add 而非 setx 以避免 1024 字符截断限制
+reg add "HKCU\Environment" /v Path /t REG_EXPAND_SZ /d "%USERPROFILE%\bin;%PATH%" /f
 ```
 
 ---

install.bat

@@ -117,13 +117,20 @@ if "!ALREADY_IN_USERPATH!"=="1" (
             set "USER_PATH_NEW=!PCT!USERPROFILE!PCT!\bin"
         )
         rem Persist update to HKCU\Environment\Path (user scope)
-        setx Path "!USER_PATH_NEW!" >nul
+        rem Use reg add instead of setx to avoid 1024-character limit
+        echo(!USER_PATH_NEW! | findstr /C:"\"" /C:"!" >nul
+        if not errorlevel 1 (
+            echo WARNING: Your PATH contains quotes or exclamation marks that may cause issues.
+            echo Skipping automatic PATH update. Please add %%USERPROFILE%%\bin to your PATH manually.
+        ) else (
+            reg add "HKCU\Environment" /v Path /t REG_EXPAND_SZ /d "!USER_PATH_NEW!" /f >nul
             if errorlevel 1 (
                 echo WARNING: Failed to append %%USERPROFILE%%\bin to your user PATH.
             ) else (
                 echo Added %%USERPROFILE%%\bin to your user PATH.
             )
         )
+    )
 )
 
 rem Update current session PATH so codeagent-wrapper is immediately available

test_install_path.bat

@@ -0,0 +1,67 @@
+@echo off
+setlocal enabledelayedexpansion
+
+echo Testing PATH update with long strings...
+echo.
+
+rem Create a very long PATH string (over 1024 characters)
+set "LONG_PATH="
+for /L %%i in (1,1,30) do (
+    set "LONG_PATH=!LONG_PATH!C:\VeryLongDirectoryName%%i\SubDirectory\AnotherSubDirectory;"
+)
+
+echo Generated PATH length:
+echo !LONG_PATH! > temp_path.txt
+for %%A in (temp_path.txt) do set "PATH_LENGTH=%%~zA"
+del temp_path.txt
+echo !PATH_LENGTH! bytes
+
+rem Test 1: Verify reg add can handle long strings
+echo.
+echo Test 1: Testing reg add with long PATH...
+set "TEST_PATH=!LONG_PATH!%%USERPROFILE%%\bin"
+reg add "HKCU\Environment" /v TestPath /t REG_EXPAND_SZ /d "!TEST_PATH!" /f >nul 2>nul
+if errorlevel 1 (
+    echo FAIL: reg add failed with long PATH
+    goto :cleanup
+) else (
+    echo PASS: reg add succeeded with long PATH
+)
+
+rem Test 2: Verify the value was stored correctly
+echo.
+echo Test 2: Verifying stored value length...
+for /f "tokens=2*" %%A in ('reg query "HKCU\Environment" /v TestPath 2^>nul ^| findstr /I "TestPath"') do set "STORED_PATH=%%B"
+echo !STORED_PATH! > temp_stored.txt
+for %%A in (temp_stored.txt) do set "STORED_LENGTH=%%~zA"
+del temp_stored.txt
+echo Stored PATH length: !STORED_LENGTH! bytes
+
+if !STORED_LENGTH! LSS 1024 (
+    echo FAIL: Stored PATH was truncated
+    goto :cleanup
+) else (
+    echo PASS: Stored PATH was not truncated
+)
+
+rem Test 3: Verify %%USERPROFILE%%\bin is present
+echo.
+echo Test 3: Verifying %%USERPROFILE%%\bin is in stored PATH...
+echo !STORED_PATH! | findstr /I "USERPROFILE" >nul
+if errorlevel 1 (
+    echo FAIL: %%USERPROFILE%%\bin not found in stored PATH
+    goto :cleanup
+) else (
+    echo PASS: %%USERPROFILE%%\bin found in stored PATH
+)
+
+echo.
+echo ========================================
+echo All tests PASSED
+echo ========================================
+
+:cleanup
+echo.
+echo Cleaning up test registry key...
+reg delete "HKCU\Environment" /v TestPath /f >nul 2>nul
+endlocal