Summary

• Fixes detectShellType() generating PowerShell : syntax when the active shell is Git Bash, WSL, or MSYS2 on Windows
• Adds detection of Unix shell indicators (TERM, BASH_VERSION, MSYSTEM, WSL_DISTRO_NAME) before the PSModulePath check, which is always set on Windows regardless of the active shell
• Updates the docstring to reflect the new 4-level detection priority

Problem

On Windows, PSModulePath is always set by the system — even when the active shell is Git Bash. The previous logic checked PSModulePath before any Unix indicators, causing the non-interactive-env hook to prepend PowerShell :VAR='value'; syntax to every bash command. Git Bash interprets these as 15 separate command not found errors per invocation.

Root Cause

src/shared/shell-env.ts line 24: detectShellType() returned "powershell" on Windows because PSModulePath check preceded any Unix shell detection.

Fix

Inserted a check for Unix-compatible shell env vars between the SHELL and PSModulePath checks:

if (
  process.env.TERM ||           // Git Bash, WSL, MSYS2 set this (e.g. "xterm-256color")
  process.env.BASH_VERSION ||   // definitive bash indicator
  process.env.MSYSTEM ||        // MSYS2-specific ("MINGW64", "UCRT64", etc.)
  process.env.WSL_DISTRO_NAME   // WSL-specific ("Ubuntu", "Debian")
) {
  return "unix"
}

This ensures Git Bash users get export VAR=value; (Unix syntax) instead of :VAR='value'; (PowerShell syntax).

Fixes #3366

Summary by cubic

Fixes shell detection on Windows so Git Bash, WSL, and MSYS2 are treated as Unix shells. The non-interactive-env hook now emits Unix export syntax and avoids bash errors.

• Bug Fixes
  • On Windows, check BASH_VERSION, MSYSTEM, and WSL_DISTRO_NAME before PSModulePath (exclude TERM); this step is Windows-only and documented in a 4-step order.
  • detectShellType() now returns "unix" for Git Bash/WSL/MSYS2, preventing PowerShell-style prefixes in non-interactive-env.
  • Fixes [Bug]: non-interactive-env hook generates PowerShell $env: syntax on Git Bash (Windows) #3366.

^{Written for commit fd0e6e2. Summary will update on new commits.}