CONTRIBUTING.md

How to Contribute

Formatting

Starlark files should be formatted by buildifier. We suggest using a pre-commit hook to automate this. First install pre-commit, then run

pre-commit install

Otherwise later tooling on CI may yell at you about formatting/linting violations.

Updating BUILD files

Some targets are generated from sources. Currently this is just the bzl_library targets. Run bazel run //:gazelle to keep them up-to-date.

Using this as a development dependency of other rules

You'll commonly find that you develop in another WORKSPACE, such as some other ruleset that depends on rules_format, or in a nested WORKSPACE in the integration_tests folder.

To always tell Bazel to use this directory rather than some release artifact or a version fetched from the internet, run this from this directory:

OVERRIDE="--override_repository=rules_format=$(pwd)/rules_format"
echo "common $OVERRIDE" >> ~/.bazelrc

This means that any usage of @rules_format on your system will point to this folder.

Releasing

1. Determine the next release version, following semver (could automate in the future from changelog)
2. Tag the repo and push it (or create a tag in GH UI)
3. Watch the automation run on GitHub actions

Java deps

If the formatter you want to add/update has to download JVM maven libraries (i.e. doesn't provide a ready-to-use "fat jar" providing all dependencies packed together), please refer to the utils/jvm_dependencies.py script. It generates http_jar repositories for you and configures the java_binary target. We don't use jvm_rules_external because we want to depend on as few external rules as possible.