flickzeug

A Rust library for computing diffs, parsing and applying patches, and performing three-way merges.

Note: This is a fork of diffy maintained by prefix.dev.

Highlights

• Fuzzy patch application: Apply patches even when line numbers have drifted or context has slightly changed — essential for real-world patching scenarios
• Battle-tested: Used in production with thousands of real-world patches from conda-forge, the community-driven collection of conda packages

Features

• Diff creation: Compute differences between texts using Myers' diff algorithm, producing minimal edit sequences
• Patch parsing & formatting: Read and write unified diff format (compatible with git diff, diff -u, etc.)
• Fuzzy patch application: Apply patches with configurable fuzzy matching when line numbers don't align exactly, using similarity-based line matching
• Three-way merge: Merge changes from two sources against a common ancestor, with conflict detection and multiple conflict marker styles
• Binary support: All major APIs have *_bytes variants for working with non-UTF-8 content

Usage

Add flickzeug to your Cargo.toml:

[dependencies]
flickzeug = "0.4"

Creating a diff

use flickzeug::create_patch;

let original = "The quick brown fox\njumps over\nthe lazy dog.\n";
let modified = "The quick brown cat\njumps over\nthe sleepy dog.\n";

let patch = create_patch(original, modified);
println!("{}", patch);

Applying a patch

use flickzeug::{apply, Patch};

let original = "The quick brown fox\njumps over\nthe lazy dog.\n";
let patch_text = "..."; // unified diff format

let patch = Patch::from_str(patch_text).unwrap();
let result = apply(original, &patch).unwrap();

Three-way merge

use flickzeug::merge;

let base = "line1\nline2\nline3\n";
let ours = "line1\nmodified by us\nline3\n";
let theirs = "line1\nline2\nline3 changed\n";

let merged = merge(base, ours, theirs).unwrap();

License

This project is available under the terms of either the Apache 2.0 license or the MIT license.

Acknowledgments

This project is a fork of diffy by Brandon Williams. We thank the original author for their excellent work.