feat: Add `rust_lint_group` and `cargo_lints` rule to define lint groups

ParkMyCar commented 2 weeks ago

Chatted about this previously in Slack. The goal with this PR is to make it easier to define and share lint configurations for your build.

Description

The PR adds two new rules, rust_lint_group and cargo_lints. It also adds a "lints" attr to rust_library and rust_binary rules that expects a new LintsInfo provider.

rust_lint_group allows you to define Rust, Clippy, and Rustdoc lints in a BUILD file.
cargo_lints automatically generates a set of lints by reading a crate's Cargo.toml, and optionally the workspace's Cargo.toml for workspace inheritance.

Then the rustc, clippy, and rustdoc actions are all updated to check for the LintsInfo provider and appends the correct arguments so the lints take effect.

Design

Honestly this is my first large change to a set of Bazel rules, so I definitely could have done something wrong here!

The change is split into two commits, the first introduces rust_lint_group which IMO is relatively straight forward. Some attributes are defined on a rule which are then formatted into command line flags and passed around with a provider.

The second commit adds cargo_lints and is much larger, a few things worth considering:

I was back and forth a bit on using a repository_rule or a regular rule. While the repository_rule maps well to a Cargo Workspace and you'd only need to define it once, not everyone uses workspaces and so I figured a regular rule was more general.
Parsing a Cargo.toml is done via a new Rust binary called cargo_toml_info. I tried to keep the external dependencies on this binary to a minimum, it only has one at the moment which is cargo_toml and I based this change largely off of https://github.com/bazelbuild/rules_rust/pull/2772. I tried to make the tool general though so other Cargo metadata rules could use it in the future.

Tests

There aren't any! I wasn't sure where the best place to start was, any guidance here is appreciated!

ParkMyCar commented 1 week ago

Thanks for the review @illicitonion! Didn't get a chance to add tests (although I did test manually by using this in my project), will follow up with that!

illicitonion commented 2 days ago

Looks good, thanks! If we can get those tests in, let's get this merged! 🎉

bazelbuild / rules_rust