This repository contains the source code for:

• guppy: a library for performing queries on Cargo dependency graphs
• cargo-guppy: a command-line frontend for the guppy library

The code in this repository is in a pre-release state and is under active development.

guppy and cargo-guppy can be used to solve many practical problems related to dependency graphs in large Rust codebases. Some examples -- all of these are available through the guppy library, and will eventually be supported in the cargo-guppy CLI as well:

• track existing dependencies for a crate or workspace
• query direct or transitive dependencies of a subset of packages — useful when some packages have greater assurance or reliability requirements
• figure out what's causing a particular crate to be included as a dependency
• iterate over reverse dependencies of a crate in topological order
• iterate over some or all links (edges) in a dependency graph, querying if the link is a build, dev or regular dependency
• filter out dev-only dependencies while performing queries, since they're typically not included in release builds
• print out a dot graph for a subset of crates, for formatting with graphviz

Still to come:

• receive CI feedback if a dependency is added, updated or removed
• receive CI feedback if a package goes from not being included in a high-assurance subset to being included
• queries based on features
• evaluation of target specs for platform-specific dependencies
• a command-line query language

This code has been written for the Libra Core project, but it may be useful for other large Rust projects.

guppy is written on top of the excellent petgraph library. It is a separate codebase from cargo, depending only on the stable cargo metadata format. (Some other tools in this space like cargo-tree use cargo internals directly.)

See the CONTRIBUTING file for how to help out.

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