sigdiff

A signature-level code diff tool. Instead of showing line-by-line changes, sigdiff extracts function, struct, class, and other symbol signatures from your codebase and tracks their changes at the semantic level.

Built with tree-sitter for fast, accurate parsing across multiple languages.

Features

• Signature map -- List all function/struct/class/trait signatures in a repository
• Signature diff -- Show added, removed, and modified signatures between git commits or the working tree
• Cross-file references -- Trace which files use or are used by a given file's definitions
• Multi-language -- Rust, Python, TypeScript/JavaScript (including JSX/TSX), Go, Java
• Filtering -- By language, visibility (public/private), signature kind, name pattern, directory depth
• Output formats -- Colored terminal text or JSON
• Caching -- Signatures are cached by file mtime for fast repeated scans

Installation

cargo install --path .

Or build from source:

git clone https://github.com/awakenworks/sigdiff.git
cd sigdiff
cargo build --release
# Binary is at target/release/sigdiff

Feature flags

All language providers are enabled by default. Disable unneeded ones to reduce binary size:

cargo install --path . --no-default-features --features lang-rust,lang-python

Available features: lang-rust, lang-python, lang-ts, lang-go, lang-java

Usage

sigdiff map -- Show all signatures

# Show all signatures in the repo
sigdiff map

# Filter to a specific directory
sigdiff map src/

# Filter by language and visibility
sigdiff map --lang rust --public-only

# Filter by kind (function, method, struct, enum, trait, class, interface, const, module)
sigdiff map --kind struct,trait

# Search by name pattern (case-insensitive)
sigdiff map --grep Provider

# JSON output
sigdiff map --format json

# Limit output size (approximate token budget)
sigdiff map --max-tokens 2000

Example output:

crates/sigdiff-core/src/diff.rs:
    pub enum SignatureChange
    pub struct FileDiff
    pub fn diff_signatures(old: &[Signature], new: &[Signature]) -> Vec<SignatureChange>
    pub fn diff_file_signatures(...)  -> Vec<FileDiff>

crates/sigdiff-core/src/filter.rs:
    pub struct MapFilter
    pub fn apply(&self, files: &[FileSignatures]) -> Vec<FileSignatures>
    pub fn parse_kind(s: &str) -> Option<SignatureKind>

sigdiff diff -- Signature-level diff

# Diff working tree against HEAD
sigdiff diff

# Diff between two commits
sigdiff diff HEAD~3..HEAD

# Diff a single ref against HEAD
sigdiff diff main

# JSON output
sigdiff diff --format json

Example output:

src/lib.rs:
+   pub fn new_feature(config: &Config) -> Result<()>
-   pub fn deprecated_fn()
~   pub fn update(data: &[u8])
    ->  pub fn update(data: &[u8], opts: Options)

sigdiff refs -- Cross-file references

# Show what a file uses and what uses it
sigdiff refs src/main.rs

# Show only outgoing references
sigdiff refs --direction uses src/main.rs

# Show only incoming references
sigdiff refs --direction used-by src/lib.rs

sigdiff langs -- List supported languages

sigdiff langs

rust: .rs
python: .py
typescript: .ts, .tsx, .js, .jsx
go: .go
java: .java

Architecture

sigdiff is organized as a Cargo workspace:

Crate	Purpose
sigdiff	CLI binary
sigdiff-core	Core library: diff engine, filter, git integration, caching, rendering
sigdiff-lang-rust	Rust language provider
sigdiff-lang-python	Python language provider
sigdiff-lang-ts	TypeScript/JavaScript provider
sigdiff-lang-go	Go language provider
sigdiff-lang-java	Java language provider

Each language provider implements the LanguageProvider trait and uses tree-sitter for parsing.

Adding a new language

1. Create a new crate crates/sigdiff-lang-<name>/
2. Implement the LanguageProvider trait from sigdiff-core
3. Add the crate to the workspace in Cargo.toml
4. Register it in src/main.rs behind a feature flag

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Ensure all tests pass: cargo test --all
4. Ensure clippy is clean: cargo clippy --all
5. Submit a pull request

License

Dual-licensed under MIT or Apache-2.0, at your option. See LICENSE for details.