rust-lang/cargo

Cargo is the official package manager for Rust, a systems programming language maintained by the Rust project. Its job is described in a single line at the top of the README: it downloads your Rust project's dependencies and compiles your project. When you write Rust code that depends on libraries from the wider ecosystem, Cargo is the tool that fetches them, tracks their versions, and drives the compiler. The README is short and points readers to two other documents for almost everything else. People who want to use Cargo are sent to The Cargo Book, the official user-facing documentation. People who want to work on Cargo itself are sent to the Cargo Contributor Guide. A note clarifies that the cargo binary shipped with Rust is the supported product for the wider ecosystem, while the code in this repository, used as a library, is mainly intended for Cargo's own needs and may change its APIs without much warning. Most of the rest of the README explains how to build Cargo from source. The required tools are an existing cargo and rustc, a C compiler, and git to clone the repository. Other dependencies are optional depending on platform and feature flags. pkg-config locates system libraries. OpenSSL development headers are needed on Unix unless the vendored-openssl Cargo feature is enabled, in which case OpenSSL is built from source. The README lists package names for Ubuntu and macOS, notes that on Windows the system Schannel is used instead, and adds that LibreSSL also works. The build also pulls in several C libraries by default: libcurl for network transfers, libgit2 for fetching git-based dependencies, libssh2 for SSH access to git repositories, and zlib for compression. Vendored copies of these are used unless pkg-config finds system versions, and the README recommends the vendored copies because they are the versions tested with Cargo. Once dependencies are in place, building is a clone of the repository followed by cargo build --release. The remaining sections cover extending Cargo with third-party subcommands that do not require modifying Cargo itself, with a link to a wiki list of known community subcommands. Cargo's releases happen alongside Rust releases, with detailed notes in the project changelog. Issues are reported on the GitHub issue tracker, and the project is dual-licensed under the MIT and Apache 2.0 licences, with extra notices for OpenSSL and libgit2 in the third-party file.