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:

Issue Reports

Do you need help or have a question about using Arduino CLI? Support requests should be made to Arduino CLI's dedicated board in the Arduino forum.

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

Legal requirements

Before we can accept your contributions you have to sign the Contributor License Agreement

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.
• 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 it exists.
• 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 and in the [`UPGRADING.md`][upgrading-file] file 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 code, command-line invocations, build scripts or data files when upgrading from an older version of Arduino CLI.
• Write tests for the code you wrote.
• Open your PR against the

  master

  branch.
• 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.
• Your PR must pass all CI tests before we will merge it. 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.

Prerequisites

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

• Go version 1.21 or later
• Taskfile to help you run the most common tasks from the command line

If you want to run integration tests you will also need:

• A serial port with an Arduino board attached

If you're working on the gRPC interface you will also have to:

• download and install buf our tool to compile and generate proto files

Building the source code

From the project folder root, just run:

1task build

The project uses Go modules so dependencies will be downloaded automatically. At the end of the build, you should find an

arduino-cli

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:

1task check

To run unit tests:

1task go:test

To run integration tests (these will take some time and require special setup, see following paragraph):

1task go:integration-test

Running only some tests

By default, all tests from all go packages are run. To run only unit tests from one or more specific packages, you can set the TARGETS environment variable, e.g.:

1TARGETS=./arduino/cores/packagemanager task go:test

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

1TEST_REGEX='^TestTryBuild.*' task go:test

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

1TEST_REGEX='^TestFindBoardWithFQBN$' TARGETS=./arduino/cores/packagemanager task go:test

Integration tests

Being a command line interface, Arduino CLI is heavily interactive and it has to stay consistent in accepting the user input and providing the expected output and proper exit codes. On top of this, many Arduino CLI features involve communicating with external devices, most likely through a serial port, so unit tests can only go so far in giving us confidence that the code is working.

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

Hardware requirements for running the full suite of integration tests:

An Arduino board attached to a serial port. The board must:

• Use one of the VID/PID pairs used by Arduino or their partners (as is the case with all modern official Arduino boards except the classic Nano).
• Accept uploads using the FQBN associated with that VID/PID (which will be the case unless you have installed a custom bootloader or removed the bootloader).

Note that running the integration tests will result in a sketch being uploaded to every attached Arduino board meeting the above requirements.

Software requirements for running integration tests:

A working Go environment. Chances are that you already have Go installed in your system, if this is not the case you can download the official distribution or use the package manager provided by your Operating System.

Running tests

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

1task go:integration-test

This will run the integration tests automatically.

To run specific packages you must run

go test

1go test -v github.com/arduino/arduino-cli/internal/integrationtest/lib

To run very specific test functions:

1go test -v github.com/arduino/arduino-cli/internal/integrationtest/lib -run TestLibUpgradeCommand

Dependency license metadata

Metadata about the license types of all dependencies is cached in the repository. To update this cache, run the following command from the repository root folder:

1task general:cache-dep-licenses

The necessary Licensed tool can be installed by following these instructions.

Configuration files formatting

To keep the configurations tidy and in order 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

Otherwise you can use the following tasks. To do so you'll need to install

npm

npm

Ensure the formatting is compliant by running the command:

1task general:format-prettier

When opening a new Pull Request, checks are automatically run to verify that configuration files are correctly formatted. In case of failures we might ask you to update the PR with correct formatting.

Working on docs

Documentation is provided to final users in form of static HTML content generated from a tool called MkDocs and hosted on GitHub Pages.

Local development

Most of the documentation consists of static content written over several Markdown files under the

docs

If you want to check out how the documentation would look after some local changes, you might need to reproduce what happens in the CI, generating the full documentation website from your personal computer. To run the docs toolchain locally, you need to have a few dependencies and tools installed:

• Go version 1.17 or later
• Taskfile to help you run the most common tasks from the command line
• A working Python environment, see this paragraph if you need to setup one

Before running the toolchain, perform the following operations from the root of the git repository (if you have a Python virtual environment, activate it before proceeding):

• go get -u github.com/pseudomuto/protoc-gen-doc/cmd/protoc-gen-doc
• poetry install

When working on docs, you can launch a command that will take care of generating the docs, build the static website and start a local server you can later access with a web browser to see a preview of your changes. From the root of the git repository run:

1task website:serve

If you don't see any error, hit http://127.0.0.1:8000 with your browser to navigate the generated docs.

Docs publishing

The present git repository has a special branch called

gh-pages

gh-pages

Docs formatting

To keep the documentation tidy and in order 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 unconfigured editors.

There are several ways to run Prettier. If you're using Visual Studio Code you can easily use the

prettier-vscode

Otherwise you can use the following tasks. To do so you'll need to install

npm

npm

Ensure the formatting is compliant by running the command:

1task general:format-prettier

When opening a new Pull Request, checks are automatically run to verify that documentation is correctly formatted. In case of failures we might ask you to update the PR with correct formatting.

Docs automation

In order to avoid unwanted changes to the public website hosting the Arduino CLI documentation, only Mike is allowed to push changes to the

gh-pages

Details on the documentation publishing system are available here.

Internationalization (i18n)

In order to support i18n in the CLI, any messages that are intended to be translated should be wrapped in a call to

i18n.Tr

Example usage:

1package main
2
3import (
4  "fmt"
5  "github.com/arduino/arduino-cli/internal/i18n"
6)
7
8func main() {
9  fmt.Println(i18n.Tr("Hello World!"))
10}

About

easyjson

golang library

We use the hi-performance

easyjson

task go:easyjson-generate

easyjson

go:easyjson-generate

Additional settings

If you need to push a commit that's only shipping documentation changes or example files, thus a complete no-op for the test suite, please start the commit message with the string [skip ci] to skip the build and give that slot to someone else who does need it.

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]