facet-diff

Crates.io	facet-diff
lib.rs	facet-diff
version	0.43.2
created_at	2025-06-30 16:03:02.310464+00
updated_at	2026-01-23 18:03:41.258502+00
description	Structural diffing for Facet types with human-readable output - no PartialEq required
homepage	https://facet.rs
repository	https://github.com/facet-rs/facet
max_upload_size
id	1732047
size	401,181

Amos Wenger (fasterthanlime)

documentation

README

facet-diff

Structural diffing for Facet types with human-readable output.

Overview

facet-diff computes differences between two values using reflection. It works on any type that implements Facet, without requiring manual diff implementations or PartialEq.

use facet_diff::{FacetDiff, format_diff};

let old = MyStruct { name: "alice", count: 1 };
let new = MyStruct { name: "alice", count: 2 };

let diff = old.diff(&new);
println!("{}", format_diff(&diff));
// Shows: count: 1 → 2

Features

Reflection-based: Works on any Facet type automatically
Human-readable output: Multiple output formats (colored, plain, compact)
Sequence diffing: Uses Myers' algorithm for optimal sequence alignment
Float tolerance: Configure epsilon for floating-point comparisons

Usage

Basic Diffing

use facet_diff::FacetDiff;

let diff = old_value.diff(&new_value);

if diff.is_equal() {
    println!("Values are equal");
} else {
    println!("Changes detected");
}

Formatted Output

use facet_diff::{format_diff, format_diff_compact};

// Full colored diff
let output = format_diff(&diff);

// Compact single-line format
let compact = format_diff_compact(&diff);

With Options

use facet_diff::{DiffOptions, diff_new_peek_with_options};
use facet_reflect::Peek;

let options = DiffOptions::new()
    .with_float_tolerance(0.001);

let diff = diff_new_peek_with_options(
    Peek::new(&old),
    Peek::new(&new),
    &options,
);