We start at defs.bzl, which invokes the resolver.
The resolver:
config.rs: Deserializes the Configparser.rs: Parses the Config, any Cargo.toml files, and any additional packages, into a single unified Cargo.toml fileresolver.rs: Resolves all of the crates.consolidator.rs: Patches in any WORKSPACE-specified overrides, and deals with platform-specific concerns.renderer.rs: Generates BUILD files for each crate, as well as functions that can be called from BUILD files.The code started off as a very hacky Week of Code project, and there are some clear remnants of that in the codebase - nothing is sacred, feel free to improve anything!
Some areas have unit testing, there are a few (very brittle) integration tests, and some examples.
To use a local version, first bootstrap it. See crate_universe/private/bootstrap/README.md for instructions on how to do this.
This will build crate_universe_resolver and configure bazel to use the binary you just built.
To get verbose logging, edit defs.bzl to set RUST_LOG to debug or trace instead of info. In particular, that will print out the generated Cargo.toml, and the path to the generated workspace file.
Note that you may need to bazel shutdown between Bazel commands. Hopefully not, but if you're seeing stale results, try it out. This only affects local development.
To test with the resolver built from source:
bin/test