fix(complete): skip unreadable files in fish shebang completion scan

[GrantD-ADSK]

Summary

• The conf.d-sourced fish init script (usage g completion-init fish) scans every executable on $PATH to detect a usage shebang, peek-reading the first 128 bytes of each file.
• Files that are executable but not readable by the current user (e.g. macOS's setuid-root sudo, or execute-only visudo) make fish's own redirection layer print a warning on every shell startup, since the existing read ... 2>/dev/null only silences the read builtin's stderr, not fish's own redirection-setup warning.
• This adds a test -r $file; or continue guard alongside the existing executability check, so unreadable files are skipped before the peek-read is attempted.

Fixes #706

Test plan

• cargo test -p usage-lib --lib complete::fish passes, snapshot updated via INSTA_UPDATE=always
• cargo fmt --check -p usage-lib clean
• Manually verified on macOS: applying the equivalent one-line patch to a locally generated ~/.config/fish/conf.d/usage.fish eliminates the /usr/bin/sudo / /usr/sbin/visudo warnings on new fish shells, with fish g completion-init fish output otherwise unchanged

Summary by CodeRabbit

• Bug Fixes
  • Improved shell startup behavior by skipping unreadable PATH entries during fish initialization.
  • Reduced warning messages for execute-only or setuid-like binaries, especially in macOS-related command setups.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Central YAML (base), Organization UI (inherited)

Review profile: CHILL

Plan: Pro Plus

Run ID: 1835b689-ed90-4bc5-9207-46b2c38c4130

📥 Commits

Reviewing files that changed from the base of the PR and between 67c20c2 and f170bd3.

⛔ Files ignored due to path filters (1)

• lib/src/complete/snapshots/usage__complete__fish__tests__complete_fish_init.snap is excluded by !**/*.snap

📒 Files selected for processing (1)

• lib/src/complete/fish.rs

---

📝 Walkthrough

Walkthrough

The fish completion init script's PATH scanning loop now skips files that are not readable before attempting to peek-read their contents for shebang detection, preventing fish redirection warnings on execute-only or setuid binaries during shell startup.

Changes

Fish completion readability fix

Layer / File(s)	Summary
Skip unreadable executables lib/src/complete/fish.rs	Added test -r $file; or continue guard in the PATH scanning loop to skip files that aren't readable before reading their first bytes to detect the usage shebang.

Estimated code review effort: 1 (Trivial) | ~3 minutes

Possibly related issues

• open: Permission denied on Fedora (and Fish) #684: Both changes modify the same fish completion init function to skip unreadable execute-only PATH entries and avoid Fish permission warnings.

Poem

A rabbit hopped through PATH so wide,
Found sudo locked, and stepped aside.
No more warnings, no more fuss,
Just quiet shells for all of us.
🐇✨ test -r, and off we hop!

🚥 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 matches the main change: skipping unreadable files during fish shebang completion scanning.
Linked Issues check	✅ Passed	The patch adds the requested readability guard for the fish shebang scan, which should prevent warnings on unreadable executable PATH entries.
Out of Scope Changes check	✅ Passed	Only the requested fish completion scan change is evident; no unrelated edits are shown in the reviewed files.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[greptile-apps]

Greptile Summary

Guards the shebang peek-read in the generated fish init script with a test -r $file readability check so that execute-only binaries (e.g., macOS's sudo, visudo) are skipped before fish's redirection layer is invoked, eliminating spurious warnings on every shell startup.

• lib/src/complete/fish.rs: Inserts test -r $file; or continue (with explanatory comment) immediately after the existing -f -x check and before read -l -n 128 first <$file, keeping the logic correct and the change minimal.
• Snapshot updated: The insta snapshot for complete_fish_init is updated to reflect the four new lines, confirming the generated script matches the template.

Confidence Score: 5/5

This is a safe, single-line guard addition with no behavioral change for readable files.

The change is a one-line fish conditional inserted at the right point in the loop — after the executability check, before the file redirection — so files that already pass the -r test are completely unaffected. The comment is accurate, the snapshot is updated, and there is no logic that could regress existing behavior.

No files require special attention.

Important Files Changed

Filename	Overview
lib/src/complete/fish.rs	Adds test -r $file; or continue guard before the peek-read to skip execute-only files such as setuid binaries, with an explanatory comment.
lib/src/complete/snapshots/usage__complete__fish__tests__complete_fish_init.snap	Snapshot updated to mirror the four new lines added to the generated fish init script; content matches the source template exactly.

_{Reviews (1): Last reviewed commit: "fix(complete): skip unreadable files in ..." | Re-trigger Greptile}