rules_fawltydeps

Bazel rules for FawltyDeps to automatically check Python dependencies in your Bazel projects.

Overview

rules_fawltydeps provides Bazel rules and aspects to integrate FawltyDeps into your build process. FawltyDeps finds undeclared and unused dependencies in Python projects, helping you maintain clean and accurate dependency declarations in your BUILD files.

Features

• Automatic dependency checking: Validate that your Python code only uses declared dependencies
• Aspect-based analysis: Non-invasive checks that work with existing py_library, py_binary, and py_test rules
• Build integration: Runs as part of your normal Bazel build process

Installation

Add the following to your MODULE.bazel file:

bazel_dep(name = "rules_fawltydeps", version = "0.1.0")

Usage

Basic Usage with Aspects

To check dependencies for a specific target:

bazel build //your/package:target --aspects=@rules_fawltydeps//fawltydeps:defs.bzl%fawltydeps_aspect

In BUILD Files

You can also create explicit check targets:

load("@rules_fawltydeps//fawltydeps:defs.bzl", "fawltydeps_check")

py_library(
    name = "mylib",
    srcs = ["mylib.py"],
    deps = [
        "@pypi//requests",
    ],
)

fawltydeps_check(
    name = "mylib_deps_check",
    target = ":mylib",
)

Then run:

bazel test :mylib_deps_check

Example

See the examples directory for a complete working example.

How It Works

The fawltydeps_aspect traverses your build graph and:

1. Collects all Python source files
2. Analyzes imports in those files
3. Compares imports against declared dependencies
4. Reports any missing or unused dependencies

Requirements

• Bazel 6.0 or later
• Python 3.8 or later

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

This project is licensed under the same terms as FawltyDeps.