Rust Clippy

• rust_clippy
• rust_clippy_aspect

Overview

Clippy is a tool for catching common mistakes in Rust code and improving it. An expansive list of lints and the justification can be found in their documentation.

Setup

Simply add the following to the .bazelrc file in the root of your workspace:

build --aspects=@rules_rust//rust:defs.bzl%rust_clippy_aspect
build --output_groups=+clippy_checks

This will enable clippy on all Rust targets.

Note that targets tagged with no-clippy will not perform clippy checks

To use a local clippy.toml, add the following flag to your .bazelrc. Note that due to the upstream implementation of clippy, this file must be named either .clippy.toml or clippy.toml. Using a custom config file requires Rust 1.34.0 or newer.

build --@rules_rust//:clippy.toml=//:clippy.toml

rust_clippy

Executes the clippy checker on a specific target.

Similar to rust_clippy_aspect, but allows specifying a list of dependencies within the build system.

For example, given the following example targets:

load("@rules_rust//rust:defs.bzl", "rust_library", "rust_test")

rust_library(
    name = "hello_lib",
    srcs = ["src/lib.rs"],
)

rust_test(
    name = "greeting_test",
    srcs = ["tests/greeting.rs"],
    deps = [":hello_lib"],
)

Rust clippy can be set as a build target with the following:

load("@rules_rust//rust:defs.bzl", "rust_clippy")

rust_clippy(
    name = "hello_library_clippy",
    testonly = True,
    deps = [
        ":hello_lib",
        ":greeting_test",
    ],
)

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
deps	Rust targets to run clippy on.	List of labels	optional	[]

rust_clippy_aspect

Executes the clippy checker on specified targets.

This aspect applies to existing rust_library, rust_test, and rust_binary rules.

As an example, if the following is defined in examples/hello_lib/BUILD.bazel:

load("@rules_rust//rust:defs.bzl", "rust_library", "rust_test")

rust_library(
    name = "hello_lib",
    srcs = ["src/lib.rs"],
)

rust_test(
    name = "greeting_test",
    srcs = ["tests/greeting.rs"],
    deps = [":hello_lib"],
)

Then the targets can be analyzed with clippy using the following command:

$ bazel build --aspects=@rules_rust//rust:defs.bzl%rust_clippy_aspect               --output_groups=clippy_checks //hello_lib:all

ASPECT ATTRIBUTES

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required