[jdx]

Summary

• preserve symlinks while copying mounted DMG contents instead of following them
• always attempt to detach a mounted DMG when copying fails
• add a regression test covering a directory symlink cycle

Root cause

DMG images commonly contain an Applications symlink. The generic recursive copy followed that link into the host /Applications directory, eventually encountering a symlink loop in the installed Xcode SDK. Returning from that copy error also skipped hdiutil detach, leaving the image mounted.

Impact

mise bootstrap packages apply can extract DMG-backed brew casks without traversing the host filesystem or leaking mounts after copy failures.

Validation

• cargo fmt --all -- --check
• cargo test --all-features file::tests::test_copy_dir_all_preserve_symlinks_does_not_follow_loops
• real brew-cask:kitty bootstrap reached successful DMG copy and ejection; it then stopped at the separate existing on_system_conditional limitation

---

Note

Medium Risk
Changes filesystem behavior on macOS for all un_dmg callers (aqua DMG installs and brew cask bootstrap); scope is localized but mistakes could still corrupt installs or leave mounts attached.

Overview
DMG extraction now copies mounted volume contents with copy_dir_all_preserve_symlinks instead of the generic recursive copy, so entries like an Applications symlink are recreated rather than followed into the host filesystem (avoiding symlink loops and accidental traversal of /Applications).

un_dmg always runs hdiutil detach after the copy attempt, surfacing copy failures first and attaching detach errors when both fail.

Adds a Unix regression test for a self-referential directory symlink alongside normal file copy.

^{Reviewed by Cursor Bugbot for commit 057e15a. Bugbot is set up for automated code reviews on this repo. Configure here.}

Summary by CodeRabbit

• Bug Fixes
  • Improved DMG extraction to preserve symbolic links and avoid following symlink loops.
  • Ensured the mounted disk image is detached even if copying its contents fails.
  • Improved reliability when copying directories that contain symbolic links.

[coderabbitai]

📝 Walkthrough

Walkthrough

DMG extraction now copies mounted contents without following symlinks, recreates symlink targets, always attempts detachment, and tests loop-like symlink handling on Unix.

Changes

DMG symlink-preserving copy

Layer / File(s)	Summary
Symlink-aware directory copy src/file.rs	Adds a helper that recreates directories, copies regular files, and preserves symlinks without following them; a Unix test validates loop-like symlink handling.
DMG extraction integration src/file.rs	Updates un_dmg to use the new helper, always run hdiutil detach, and select copy or detach errors based on their results.

Estimated code review effort: 2 (Simple) | ~10 minutes

Poem

Through folders I hop,
A link points back—still I stop,
Files land safe and bright.
DMG bids farewell,
Symlinks keep their little spell,
Then moonrise crowns the night.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 57.14% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
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.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: preserving symlinks during DMG extraction in bootstrap.

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[greptile-apps]

Greptile Summary

This PR fixes a symlink-loop crash in DMG extraction by replacing the generic recursive copy (which followed symlinks) with a new copy_dir_all_preserve_symlinks helper that walks with follow_links(false) and recreates symlinks verbatim. It also ensures hdiutil detach always runs after copy, chaining both errors when they both fail.

• copy_dir_all_preserve_symlinks uses WalkDir with follow_links(false), yielding directory symlinks as symlink entries (not traversed), file symlinks preserved via make_symlink, and regular files copied with fs::copy. This correctly avoids following Applications -> /Applications (or self-referential) links in DMGs.
• un_dmg now captures the copy result, unconditionally calls hdiutil detach, and reports both errors via wrap_err_with when both fail — a clean improvement over the original that leaked mounts on copy failure.
• A Unix regression test validates that a source/Applications -> . cycle is preserved as a symlink rather than traversed.

Confidence Score: 5/5

Safe to merge; the scope is narrow (macOS DMG extraction only), the logic is straightforward, and a targeted regression test covers the loop-avoidance behavior.

The new helper correctly handles directory symlinks, file symlinks, and regular files without following loops. The un_dmg error-handling rewrite is clean and covers all four outcome combinations. No edge cases appear to be missed.

No files require special attention.

Important Files Changed

Filename	Overview
src/file.rs	Adds copy_dir_all_preserve_symlinks (preserves symlinks, avoids loops) and updates un_dmg to use it; also fixes detach-always-runs and chains both errors when copy+detach both fail. Regression test included.

_{Reviews (2): Last reviewed commit: "fix(bootstrap): report dmg detach failur..." | Re-trigger Greptile}

[github-actions]

Hyperfine Performance

mise x -- echo

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.7.5 x -- echo	20.3 ± 0.9	18.4	24.0	1.00
mise x -- echo	20.9 ± 1.2	18.9	34.0	1.03 ± 0.08

mise env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.7.5 env	19.8 ± 0.9	17.9	25.8	1.00
mise env	20.3 ± 1.0	18.4	24.9	1.03 ± 0.07

mise hook-env

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.7.5 hook-env	20.5 ± 0.9	18.7	25.5	1.00
mise hook-env	20.9 ± 0.9	19.1	24.4	1.02 ± 0.06

mise ls

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
mise-2026.7.5 ls	17.7 ± 0.8	16.2	21.9	1.00
mise ls	18.3 ± 0.9	16.9	22.9	1.04 ± 0.07

xtasks/test/perf

Command	mise-2026.7.5	mise	Variance
install (cached)	166ms	165ms	+0%
ls (cached)	61ms	60ms	+1%
bin-paths (cached)	63ms	64ms	-1%
task-ls (cached)	126ms	128ms	-1%