fix(task): honor MISE_CYGDRIVE_PREFIX for Git Bash, not only Cygwin

[JamBalaya56562]

Problem

PR #10147 added Cygwin support to the Windows→Unix PATH conversion, with MISE_CYGDRIVE_PREFIX as an escape hatch for a non-default cygdrive automount root configured in /etc/fstab.

As pointed out in review feedback (thanks @lewis-yeung), the cygdrive automount mechanism is also present in MSYS2 / Git Bash (a Cygwin derivative), where the mount root is likewise configurable in /etc/fstab (default /, i.e. /c/...).

msys_drive_prefix_for returned an empty prefix immediately for any non-Cygwin bash and never read MISE_CYGDRIVE_PREFIX, so a Git Bash user with a custom automount root got a corrupted /c/... PATH with no way to fix it — the same class of bug #10147 set out to address, still present for Git Bash.

Fix

• is_cygwin_shell now only selects the default prefix when no override is set: empty for Git Bash / MSYS2 (/c/...), /cygdrive for Cygwin (/cygdrive/c/...).
• MISE_CYGDRIVE_PREFIX is now honored for both shells. The relative-value warning reports the shell-appropriate default.

No behavior change for existing users: Git Bash without an override still emits /c/..., Cygwin without an override still emits /cygdrive/c/.... The only new behavior is that a Git Bash user can now set a custom prefix.

Tests

• Added test_maybe_convert_env_for_msys_shell_honors_cygdrive_prefix_for_git_bash (Git Bash + MISE_CYGDRIVE_PREFIX=/mnt → /mnt/c/...).
• Existing Git Bash (/c/...) and Cygwin (/cygdrive/...) tests still guard the defaults.
• Verified the full binary builds and all path:: unit tests pass; the #[cfg(windows)] prefix logic was exercised standalone across all input combinations.

Follow-up to #10147.

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This PR was generated by an AI coding assistant.

Summary by CodeRabbit

• Documentation

  • Expanded Windows troubleshooting guide with clearer instructions for configuring cygdrive mount roots and using MISE_CYGDRIVE_PREFIX, including absolute-path requirements and behavior when set to "/".

• Bug Fixes

  • Improved Windows PATH conversion for POSIX shells (Cygwin, MSYS2/Git Bash) to honor custom cygdrive prefixes and produce correct converted paths.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Configuration used: defaults

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Run ID: 5ec2d7e1-531b-47a2-8fd7-a388f134c6fe

📥 Commits

Reviewing files that changed from the base of the PR and between ad8e3d4 and 86f802a.

📒 Files selected for processing (1)

• src/task/task_executor.rs

🚧 Files skipped from review as they are similar to previous changes (1)

• src/task/task_executor.rs

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📝 Walkthrough

Walkthrough

This PR enhances Windows PATH conversion for POSIX shells by making cygdrive prefix detection shell-aware. The msys_drive_prefix_for function now dynamically computes whether to use /cygdrive (Cygwin) or /mnt (MSYS2/Git Bash) as the default prefix, improves warnings for invalid MISE_CYGDRIVE_PREFIX overrides, adds test coverage for Git Bash, and expands troubleshooting documentation.

Changes

Windows PATH Conversion for POSIX Shells

Layer / File(s)	Summary
Dynamic shell-type-aware cygdrive prefix detection src/task/task_executor.rs	msys_drive_prefix_for now detects whether the target program is Cygwin or MSYS2/Git Bash and computes the appropriate default cygdrive prefix (/cygdrive vs /mnt). Warning text for non-absolute MISE_CYGDRIVE_PREFIX values reflects the computed default. New test verifies Git Bash respects the MISE_CYGDRIVE_PREFIX override for path conversion.
Windows troubleshooting documentation docs/troubleshooting.md	Expanded the custom cygdrive mount root subsection to explain shared behavior between Cygwin and Git Bash/MSYS2, document how to configure MISE_CYGDRIVE_PREFIX, and clarify the absolute-prefix requirement and special handling of MISE_CYGDRIVE_PREFIX=/.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Poem

🐰 A rabbit hops through Windows paths,
/cygdrive and /mnt at last align,
Git Bash now knows which way to go,
With prefix defaults so divine! ✨

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main fix: extending MISE_CYGDRIVE_PREFIX support to Git Bash in addition to Cygwin, which is the primary objective of the PR.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[greptile-apps]

Greptile Summary

This PR fixes msys_drive_prefix_for so that MISE_CYGDRIVE_PREFIX is respected for Git Bash / MSYS2 in addition to Cygwin; previously the function returned an empty prefix immediately for any non-Cygwin shell and never read the env var.

• src/task/task_executor.rs: Removes the early-return for non-Cygwin shells; the default prefix is now selected by shell type ("" for Git Bash/MSYS2, /cygdrive for Cygwin) and then MISE_CYGDRIVE_PREFIX is applied on top for both. The fallback warning message is also updated to describe the shell-appropriate default. A new test covers the Git Bash + custom prefix path.
• docs/troubleshooting.md: Updates the troubleshooting guide to document that MISE_CYGDRIVE_PREFIX works for both Cygwin and Git Bash / MSYS2, notes each shell's default mount root, and clarifies the MISE_CYGDRIVE_PREFIX=/ edge case.

Confidence Score: 5/5

Safe to merge — the change is a targeted, backwards-compatible extension of existing Windows PATH conversion logic with no behaviour change for current users.

The old early-return for non-Cygwin shells is cleanly replaced by a shell-aware default, MISE_CYGDRIVE_PREFIX is now read for both shell types, and the warning message correctly describes the fallback for each case. Existing Git Bash and Cygwin tests still pass, and a new test covers the previously-missing Git Bash + custom prefix path. The documentation update is accurate. No regressions are introduced.

No files require special attention.

Important Files Changed

Filename	Overview
src/task/task_executor.rs	Extends msys_drive_prefix_for so MISE_CYGDRIVE_PREFIX is honored for Git Bash / MSYS2, not only Cygwin; default selection and warning message are both shell-aware; new test covers the Git Bash override path.
docs/troubleshooting.md	Documentation updated to mention MSYS2 / Git Bash alongside Cygwin, note each shell's default mount root, and clarify the MISE_CYGDRIVE_PREFIX=/ edge case.

_{Reviews (2): Last reviewed commit: "test(task): clarify per-shell fallback c..." | Re-trigger Greptile}

[JamBalaya56562]

The comment in test_maybe_convert_env_for_msys_shell_rejects_relative_cygdrive_prefix still says "fall back to the default /cygdrive instead"...

Good catch — fixed. The comment now states that the fallback is the shell's default: /cygdrive for the Cygwin binary the test exercises, and an empty prefix (the /c/... form) for Git Bash. The assertion is unchanged.