fix: detect Git Bash/WSL/MSYS2 shell on Windows (non-interactive-env hook)

[Zireael]

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 uses Unix export syntax and avoids bash errors.

• Bug Fixes
  • On Windows, check Unix indicators before PSModulePath: BASH_VERSION, MSYSTEM, WSL_DISTRO_NAME (exclude TERM to avoid PowerShell false positives).
  • detectShellType() now returns "unix" for Git Bash/WSL/MSYS2, preventing PowerShell-style prefixes in non-interactive-env.
  • Docstring updated with a 4-step detection order; step 2 is Windows-only.
  • Fixes [Bug]: non-interactive-env hook generates PowerShell $env: syntax on Git Bash (Windows) #3366.

^{Written for commit 998dbde. Summary will update on new commits.}

[github-actions]

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[Zireael]

I have read the CLA Document and I hereby sign the CLA

[cubic-dev-ai]

2 issues found across 1 file

Confidence score: 3/5

• There is a concrete user-impacting risk in src/shared/shell-env.ts: using TERM as a broad Unix-shell signal can misclassify Windows PowerShell sessions and produce invalid env-prefix syntax.
• Both findings are medium severity (6/10) with high confidence (8/10), so this looks like a real behavior regression risk rather than a minor style issue.
• Pay close attention to src/shared/shell-env.ts - shell detection order/guards should avoid TERM preempting PowerShell logic, especially across Windows vs non-Windows environments.

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="src/shared/shell-env.ts">

<violation number="1" location="src/shared/shell-env.ts:27">
P2: Scope the Unix-indicator override to Windows; otherwise it can preempt the PowerShell detection on non-Windows environments when `TERM` is set.</violation>

<violation number="2" location="src/shared/shell-env.ts:28">
P2: TERM is too broad a Unix-shell indicator here; on Windows PowerShell sessions where TERM is set, this branch misclassifies the shell as unix and generates invalid env-prefix syntax.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

0 issues found across 1 file (changes from recent commits).

_{Auto-approved: Fixes incorrect PowerShell detection for Git Bash/WSL/MSYS2 on Windows. Safe as markers used are specific to Unix-like environments and the previous logic already defaulted to PowerShell.}

[Zireael]

recheck