How to contribute¶

First of all, thanks for contributing! This document provides some basic guidelines for contributing to this repository.

There are several ways you can get involved:

Type of contribution	Contribution method
- Support request - Question - Discussion	Post on the Arduino Forum
- Bug report - Feature request	Issue report (read the issue guidelines)
Beta testing	Try out the nightly build
- Bug fix - Enhancement	Pull Request (read the pull request guidelines)
Monetary	- Donate - Buy official products

Issue Reports¶

Do you need help or have a question about using Arduino Lint? Support requests should be made to the Arduino forum.

High quality bug reports and feature requests are valuable contributions to the Arduino Lint project.

Before reporting an issue¶

Give the nightly build a test drive to see if your issue was already resolved.
Search existing pull requests and issues to see if it was already reported. If you have additional information to provide about an existing issue, please comment there. You can use GitHub's "Reactions" feature if you only want to express support.

Qualities of an excellent report¶

The issue title should be descriptive. Vague titles make it difficult to understand the purpose of the issue, which might cause your issue to be overlooked.
Provide a full set of steps necessary to reproduce the issue. Demonstration code or commands should be complete and simplified to the minimum necessary to reproduce the issue.
Be responsive. We may need you to provide additional information in order to investigate and resolve the issue.
If you find a solution to your problem, please comment on your issue report with an explanation of how you were able to fix it and close the issue.

Pull Requests¶

To propose improvements or fix a bug, feel free to submit a PR.

Pull request checklist¶

In order to ease code reviews and have your contributions merged faster, here is a list of items you can check before submitting a PR:

Create small PRs that are narrowly focused on addressing a single concern.
Write tests for the code you wrote.
Maintain clean commit history and use meaningful commit messages. PRs with messy commit history are difficult to review and require a lot of work to be merged.
If your PR doesn't need to be included in the changelog, please start the commit message and PR title with the string [skip changelog]
If the PR contains a breaking change, please start the commit message and PR title with the string [breaking]. Don't forget to describe in the PR description what changes users might need to make in their workflow or application due to this PR. A breaking change is a change that forces users to change their command-line invocations or parsing of the JSON formatted output when upgrading from an older version of Arduino Lint.
PR titles indirectly become part of the CHANGELOG so it's crucial to provide a good record of what change is being made in the title; why it was made will go in the PR description, along with a link to a GitHub issue if one exists.
Open your PR against the main branch.
Your PR must pass all CI tests before we will merge it. You can run the CI in your fork by clicking the "Actions" tab and then the "I understand my workflows..." button. If you're seeing an error and don't think it's your fault, it may not be! The reviewer will help you if there are test failures that seem not related to the change you are making.

Development prerequisites¶

To build Arduino Lint from sources you need the following tools to be available in your local environment:

Go version 1.14 or later
Taskfile to help you run the most common tasks from the command line

If you want to run integration tests or work on documentation, you will also need:

A working Python environment, version 3.8 or later.
Poetry.

Building the source code¶

From the project folder root, just run: F

task build

The project uses Go modules, so dependencies will be downloaded automatically. At the end of the build, you should find the arduino-lint executable in the same folder.

Running the tests¶

There are several checks and test suites in place to ensure the code works as expected and is written in a way that's consistent across the whole codebase. To avoid pushing changes that will cause the CI system to fail, you can run most of the tests locally.

To ensure code style is consistent, run:

task check

To run all tests:

task test

Go unit tests¶

To run only the Go unit tests, run:

task go:test-unit

By default, all tests for all Arduino Lint's Go packages are run. To run unit tests for only one or more specific packages, you can set the TARGETS environment variable, e.g.:

TARGETS=./internal/rule task go:test-unit

Alternatively, to run only some specific test(s), you can specify a regex to match against the test function name, e.g.:

TEST_REGEX='^TestLibraryProperties.*' task go:test-unit

Both can be combined as well, typically to run only a specific test:

TEST_REGEX='^TestFindProjects$' TARGETS=./internal/project task go:test-unit

Integration tests¶

Being a command line interface, Arduino Lint is heavily interactive and it has to stay consistent in accepting the user input and providing the expected output and proper exit codes.

For these reasons, in addition to regular unit tests the project has a suite of integration tests that actually run arduino-lint in a different process and assess the options are correctly understood and the output is what we expect.

Running tests¶

After the software requirements have been installed, you should be able to run the tests with:

task test-integration

This will automatically install the necessary dependencies, if not already installed, and run the integration tests automatically.

To run specific tests, you must run pytest from the virtual environment created by Poetry.

poetry run pytest test/test_all.py::test_report_file

You can avoid writing the poetry run prefix each time by creating a new shell inside the virtual environment:

poetry shell
pytest test_lib.py
pytest test_lib.py::test_list

Linting and formatting¶

When editing any Python file in the project, remember to run linting checks with:

task python:check

This will run flake8 automatically and return any error in the code formatting.

In case of linting errors you should be able to solve most of them by automatically formatting with:

task python:format

Configuration files formatting¶

We use Prettier to automatically format all YAML files in the project. Keeping and enforcing a formatting standard helps everyone make small PRs and avoids the introduction of formatting changes made by unconfigured editors.

There are several ways to run Prettier. If you're using Visual Studio Code you can easily use the prettier-vscode extension to automatically format as you write.

Otherwise you can use the following tasks. To do so you'll need to install npm if not already installed. Check the official documentation to learn how to install npm for your platform.

To check if the files are correctly formatted run:

task config:check

If the output tells you that some files are not formatted correctly run:

task config:format

Checks are automatically run on every pull request to verify that configuration files are correctly formatted.

Working on documentation¶

Documentation is provided to final users in form of static HTML content generated from a tool called MkDocs and hosted on GitHub Pages: https://arduino.github.io/arduino-lint/dev/

Local development¶

The documentation consists of static content written over several Markdown files under the docs subfolder of the Arduino Lint repository, as well as the dynamically generated command line reference.

When working on the documentation, it is useful to be able to see the effect the changes will have on the generated documentation website. You can build the documentation website and serve it from your personal computer by running the command:

task docs:serve

The documentation will build. If you don't see any error, open http://127.0.0.1:8000 in your browser to local the local copy of the documentation.

Documentation formatting¶

We use Prettier to automatically format all Markdown files in the project. Keeping and enforcing a formatting standard helps everyone make small PRs and avoids the introduction of formatting changes made by misconfigured editors.

There are several ways to run Prettier. If you're using Visual Studio Code you can easily use the prettier-vscode extension to automatically format as you write.

Otherwise you can use the following tasks. To do so you'll need to install npm if not already installed. Check the official documentation to learn how to install npm for your platform.

To check if the files are correctly formatted run:

task docs:check

If the output tells you that some files are not formatted correctly run:

task docs:format

Checks are automatically run on every pull request to verify that documentation is correctly formatted.

Documentation publishing¶

The Arduino Lint git repository has a special branch called gh-pages that contains the generated HTML code for the documentation website. Every time a change is pushed to this special branch, GitHub automatically triggers a deployment to pull the change and publish a new version of the website. Do not open Pull Requests to push changes to the gh-pages branch; that will be done exclusively from the CI.

For details on the documentation publishing system, see: https://github.com/arduino/arduino-lint/blob/main/docs/build.py