Fix process crash when running Qwen Code in MSYS2 UCRT environment on Windows. The issue was caused by findGitBashPath() incorrectly selecting MSYS2's bash instead of Git Bash, which is incompatible with Windows ConPTY.

Changes:

• Add isRunningInMSYS2() and isRunningInGitBash() detection functions
• Use system default shell (cmd.exe) in MSYS2 environments
• Disable node-pty in MSYS2 to avoid ConPTY crashes
• Add unit tests for environment detection

Fixes #2306

TLDR

Problem: Qwen Code crashes when executing system commands on Windows MSYS2 UCRT environments (UCRT64, CLANG64, MSYS).

Root Cause: The findGitBashPath() function introduced in commit c2fe554e3 incorrectly selects MSYS2's bundled bash instead of Git Bash. MSYS2 bash is designed for the MSYS2 POSIX emulation layer and is incompatible with Windows ConPTY (used by node-pty), causing immediate crashes.

Solution:

1. Added environment detection functions (isRunningInMSYS2(), isRunningInGitBash()) to distinguish between MSYS2 and Git Bash environments using the MSYSTEM environment variable
2. In MSYS2 environments, use system default shell (cmd.exe via ComSpec) instead of bash - reverting to v0.11.1's working behavior
3. In Git Bash environments (MINGW64, MINGW32), continue using findGitBashPath() to locate Git Bash correctly
4. Disable node-pty in MSYS2 environments and fall back to child_process to avoid ConPTY incompatibility

Files Changed:

• packages/core/src/utils/shell-utils.ts - Added detection functions and refactored getShellConfiguration()
• packages/core/src/services/shellExecutionService.ts - Disable node-pty in MSYS2
• packages/core/src/utils/shell-utils.test.ts - Added unit tests for new detection functions

Screenshots / Video Demo

N/A

Dive Deeper

Environment Variable Analysis

Detection Logic

Why This Fix Works

• v0.11.1 behavior restored for MSYS2: Before commit c2fe554e3, MSYS2 environments worked correctly because they used the system default shell
• Git Bash still optimized: Git Bash environments continue to benefit from the findGitBashPath() fix for users who have Git Bash installed
• No regression: Linux, macOS, and standard Windows (cmd/PowerShell) users are unaffected

Reviewer Test Plan

1. MSYS2 UCRT64 environment (primary fix validation):

   • Install MSYS2 with UCRT64 toolchain
   • Launch UCRT64 terminal
   • Run qwen and execute any shell command (e.g., ls, pwd, echo test)
   • Verify: No crash, command executes successfully via cmd.exe

2. Git Bash environment (regression test):

   • Launch Git Bash terminal
   • Run qwen and execute shell commands
   • Verify: Commands execute using Git Bash correctly

3. Standard Windows environments (regression test):

   • cmd.exe: Run qwen and verify commands work
   • PowerShell: Run qwen and verify commands work

4. Run unit tests:

   npm run test -- packages/core/src/utils/shell-utils.test.ts

   • Verify: All 14 new test cases pass (6 for isRunningInMSYS2, 8 for isRunningInGitBash)

5. Type checking:

   npm run typecheck

Testing Matrix

Notes:

• macOS (🍏) and Linux (🐧): No changes to Unix shell handling, existing behavior preserved
• Windows (🪟): Primary platform for this fix - tested in MSYS2 UCRT64, Git Bash, cmd.exe, and PowerShell

Linked issues / bugs

Fixes #2306