Fast, accurate file and folder comparison for macOS.
A native SwiftUI app inspired by Beyond Compare — no WebView, no cloud upload.
Mac App Store · Website · 中文说明 · Changelog · Contributing
Browse a recursive, filterable tree and jump directly from a changed file into its text diff.
Review aligned lines, character-level edits, totals, and previous/next difference navigation side by side.
- Accurate: byte-exact folder validation, shortest edit scripts for normal changes, visible final-newline differences, and correct handling of symbolic links, packages, and file/folder conflicts.
- Fast at scale: 100,000-line text comparisons complete in about 0.06 seconds; a 10,000-file folder benchmark completes in about 0.38 seconds on the development machine.
- Easy to read: side-by-side lines, character-level highlights, aligned line numbers, difference counts, and previous/next navigation.
- Native and private: a responsive macOS interface, local-only processing, and sandboxed read/write access limited to folders you explicitly select.
- Adaptive Myers line diff with low-occurrence anchors for large rewrites
- Character-level highlighting inside modified lines
- Search and line navigation, comparison rules, syntax colors, and optional line wrapping
- Hunk-level left/right acceptance, editable output, and unified diff/patch export
- Added, removed, and modified counts with keyboard-friendly navigation
- CRLF/LF normalization, final-newline reporting, and binary-file detection
- Memory-mapped input to avoid duplicating large files in memory
- Three-way base/ours/theirs merge with explicit conflict resolution
- Branch, commit, index, and working-tree comparison without changing repository state
- Standalone CLI plus Git difftool/mergetool configuration
- Finder Quick Action support through the built-in Compare Files shortcut
- Image side-by-side, opacity overlay, dimensions, pixel metrics, and difference heatmap
- Semantic JSON and plist comparison with stable paths and object-key-order independence
- Recursive expandable tree with Same, Different, Left Only, and Right Only states
- All/Differences/Left Only/Right Only filters with automatic expansion of changed folders
- Type and size prechecks followed by exact, bounded-parallel byte validation
- Correct traversal of package directories and comparison of symbolic-link targets
- Fast subtree filtering through pre-aggregated status indexes
- Per-item and multi-row Left → Right / Right → Left operation planning
- Preflight review with real item/byte counts, overwrite warnings, progress, cancellation, and per-item results
- Safe copy, backup-before-replace, destination-empty move, and recoverable Move to Trash
- Durable undo history with changed-output protection, including across app relaunches; cross-volume moves are copied and byte-verified before the source enters Trash
- Explicit stop/continue failure policies plus transfer speed and estimated remaining time during execution
- Import/export of safe
.grapeplanrecipes that remap validated relative operations to the current folder pair
The contracts and acceptance criteria are documented in the v1.3 safe-operations plan, the v1.4 durable-workflows plan, the v1.5 text-actions plan, and the v1.6–v1.8 integration contract.
The repository includes a Release benchmark with reproducible generated fixtures. Representative results from the development machine:
| Scenario | Result | Notes |
|---|---|---|
| 100k-line sparse edit | 0.060 s | End-to-end: split, diff, inline ranges, rows |
| 30k-line high churn | 0.070 s | Retains all stable structural anchors |
| 10k-file folder | 0.382 s | Down from 2.385 s, about 6.2× faster |
| 50k-file folder | 3.917 s | Full scan, validation, tree, sort, rollup |
Timings exclude fixture generation and vary by hardware and storage. Run them locally:
bash macos/Benchmarks/run-benchmarks.sh
bash macos/Benchmarks/run-benchmarks.sh 100000 50000The diff design builds on Myers' O(ND) algorithm and the low-occurrence anchoring ideas documented in Git's diff algorithms.
Install the signed release from the Mac App Store.
To build from source, use macOS 26+ and Xcode 26+:
xcodebuild -project macos/GrapeCompare.xcodeproj \
-scheme GrapeCompare \
-destination 'platform=macOS' \
-configuration Debug buildYou can also open macos/GrapeCompare.xcodeproj in Xcode and press Run.
bash macos/CLI/build.sh
macos/CLI/.build/grapecompare diff left.txt right.txt --patch
macos/CLI/.build/grapecompare merge base.txt ours.txt theirs.txt merged.txt
macos/CLI/.build/grapecompare git-configThe printed Git mergetool configuration launches the GUI and reports success only after the merged output is saved. Arbitrary Git temporary paths require a directly distributed build with suitable filesystem access; the App Store sandbox only grants access to files selected through system UI.
Two folders open the folder comparison; other inputs open the file comparison. The App Store build is sandboxed and cannot read arbitrary command-line paths. Build with App Sandbox disabled if this workflow is required.
Run the platform-independent core suite without launching Xcode:
bash macos/Tests/run-tests.sh
bash macos/CLI/run-tests.shThe suite contains focused comparison and transaction checks, 300 randomized shortest-edit-script cases, large-text stress cases, and filesystem safety cases. Pull requests run the same suite in GitHub Actions.
macos/
├── GrapeCompare/
│ ├── Core/
│ │ ├── DiffEngine.swift # adaptive Myers + low-occurrence anchors
│ │ ├── FolderComparator.swift # POSIX scan + bounded exact validation
│ │ └── FileOperations.swift # preflight, transactions, verification + undo
│ ├── Views/ # native SwiftUI file/folder interfaces
│ └── AppState.swift # comparison orchestration
├── Tests/ # deterministic correctness and stress tests
└── Benchmarks/ # repeatable large-file/folder benchmarks
Contributions are welcome. Read CONTRIBUTING.md before opening a pull request. For help, use GitHub Issues; report security problems according to SECURITY.md. By participating, you agree to follow the Code of Conduct.