Fix panic in oxen diff outside repo

[rpschoenburg]

Changes a panic to an error.

No important or functional difference in the code

Summary by CodeRabbit

• Bug Fixes

  • Improved error handling with enhanced messages when repository initialization fails
  • Added validation to ensure both file paths are provided for file comparison mode

• New Features

  • Diff command now supports direct file-to-file comparison as a fallback when repository context is unavailable

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

Walkthrough

When repository initialization fails, the diff operation now falls back to direct file-path comparison instead of only erroring. The change captures path arguments, validates path_2 presence, calls diff_files with both paths, and wraps the result in a Vec. Existing repo-based behavior is preserved.

Changes

Cohort / File(s)	Summary
Error fallback and file-path handling oxen-rust/src/lib/src/repositories/diffs.rs	Added fallback to file-diff comparison when repo initialization fails; implemented path_2 validation with error messaging ("requires a repo or file paths"); calls diff_files with captured path_1 and path_2; returns single DiffResult wrapped in Vec; preserves successful repo path behavior

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

• Straightforward error-handling enhancement with a single-path fallback mechanism
• Changes are localized to one file with no API surface modifications
• Logic is relatively clear and defensive (guards for path existence)
• No complex interactions or multi-component coordination

Possibly related PRs

• fix uncommitted file diff #118: Refactored file-level diff calls and made FileNode and file-path inputs optional; directly relates to the fallback file-diff mechanism added here
• add diff compatibilty #91: Modified callers to pass DiffOpts into repositories::diffs::diff; operates on the same diff codepath being enhanced here
• Oxen-AI/Oxen#498: Earlier modifications to diff handling in diffs.rs when repo/head info is missing; shares similar error-recovery patterns

Suggested reviewers

• jcelliott

Poem

🐰 When repos go missing, fear not!

A rabbit hops to the rescue plot,

With file paths bright and errors clear,

The fallback's here—no need to fear! ✨

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Fix panic in oxen diff outside repo' directly and clearly summarizes the main change: converting a panic to an error when oxen diff is used outside a repository.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch Bug/diff_panic

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[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (1)

oxen-rust/src/lib/src/repositories/diffs.rs (1)

84-104: Repo init failure fallback looks good; consider guarding against revision-based invocations

The new handling on LocalRepository::from_* error is solid: the panic/unwrap on path_2 is gone, you return a clear OxenError when path_2 is missing, and otherwise cleanly fall back to diff_files(path_1, path_2, …) and wrap the result in a Vec. The early return also means moving opts.path_1 here is safe and doesn’t affect the later match on (opts.path_2, opts.revision_1, opts.revision_2).

One subtle behavior change to think about: if revision_1 or revision_2 are set but opening the repo fails, this branch will still run the plain file diff and silently ignore the revision options. That might surprise users who thought they were diffing specific revisions. You might want to:

• Only take the direct file-path fallback when revision_1.is_none() and revision_2.is_none(), and otherwise return an error explaining that revision-based diffs require a valid repo, or
• Include the presence of revisions in the error message instead of attempting diff_files.

Functionally this is already a big improvement over panic, so this is mostly about tightening semantics and UX around revision arguments.

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between f8b2567 and 4e7726c.

📒 Files selected for processing (1)

• oxen-rust/src/lib/src/repositories/diffs.rs (1 hunks)

🧰 Additional context used

🧠 Learnings (2)

📓 Common learnings

Learnt from: Lilianxr
Repo: Oxen-AI/Oxen PR: 146
File: oxen-rust/src/benches/oxen/download.rs:176-179
Timestamp: 2025-09-18T19:11:42.443Z
Learning: In oxen-rust/src/benches/oxen/download.rs, the setup_repo_for_download_benchmark function always stages files under a "files" directory structure in the repository, regardless of whether data_path is provided or not. The hardcoded Path::new("files") in the repositories::download call is correct because of this consistent setup.

📚 Learning: 2025-09-18T19:11:42.443Z

Learnt from: Lilianxr
Repo: Oxen-AI/Oxen PR: 146
File: oxen-rust/src/benches/oxen/download.rs:176-179
Timestamp: 2025-09-18T19:11:42.443Z
Learning: In oxen-rust/src/benches/oxen/download.rs, the setup_repo_for_download_benchmark function always stages files under a "files" directory structure in the repository, regardless of whether data_path is provided or not. The hardcoded Path::new("files") in the repositories::download call is correct because of this consistent setup.

Applied to files:

• oxen-rust/src/lib/src/repositories/diffs.rs

🧬 Code graph analysis (1)

oxen-rust/src/lib/src/repositories/diffs.rs (1)

oxen-rust/src/lib/src/error.rs (1)

• basic_str (158-160)

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