Please take a moment to review this document in order to make the contribution process easy and effective for everyone involved.

Following these guidelines helps to communicate that you respect the time of the developers managing and developing this open source project.

In return, they should reciprocate that respect in addressing your issue or assessing patches and features.

## Using the issue tracker

The [issue tracker](https://github.com/OpenTTD/OpenTTD/issues) is the preferred channel for [bug reports](#bug-reports), but please respect the following restrictions:

* Please **do not** use the issue tracker for help playing or using OpenTTD.

* Please **do not** derail or troll issues. Keep the discussion on topic and respect the opinions of others.

* Please **do not** post comments consisting solely of "+1" or ":thumbsup:".

Use [GitHub's "reactions" feature](https://github.com/blog/2119-add-reactions-to-pull-requests-issues-and-comments) instead.

We reserve the right to delete comments which violate this rule.

* Please **do not** open issues or pull requests regarding add-on content in NewGRF, GameScripts, AIs, etc.

* Please use [the web translator](https://translator.openttd.org/) to submit corrections and improvements to translations of the game.

## Bug reports

A bug is a _demonstrable problem_ that is caused by the code in the repository.

Good bug reports are extremely helpful, so thanks!

Guidelines for bug reports:

0. Please don't report issues with games where you changed NewGRFs mid-game. (This can be verified with the `gamelog` console command in-game.)

## Pull requests

Good pull requests—patches, improvements, new features—are a fantastic help.

Pull requests should fit with the [goals of the project](./CONTRIBUTING.md#project-goals).

**Please do ask first** before embarking on any significant pull request (e.g. implementing features, refactoring code, porting to a different language), otherwise you risk spending a lot of time working on something that the project's developers might not want to merge into the project.

Every pull request should have a clear scope, with no unrelated commits.

Adhering to the following process is the best way to get your work included in the project:

1. [Fork](https://help.github.com/fork-a-repo/) the project, clone your fork, and configure the remotes:

```bash

git clone https://github.com/<your-username>/OpenTTD.git openttd

git clone https://github.com/OpenTTD/OpenTTD-git-hooks.git openttd_hooks

cd openttd

git remote add upstream https://github.com/OpenTTD/OpenTTD.git

cd .git/hooks

ln -s ../../../openttd_hooks/hooks/* .

```bash

git fetch upstream

```

3. Create a new topic branch (off the main project development branch) to

contain your feature, change, or fix:

```bash

git checkout upstream/master -b <topic-branch-name>

```

Use Git's [interactive rebase](https://docs.github.com/en/get-started/using-git/about-git-rebase) feature to tidy up your commits before making them public.

5. Locally rebase the upstream development branch into your topic branch:

```bash

git fetch upstream

git rebase upstream/master

```

6. Push your topic branch up to your fork the first time:

```bash

**IMPORTANT**: By submitting a pull request or patch, you agree to the [License](#license) and the [Privacy Notice](CONTRIBUTING.md#privacy-notice).

### Pull request validation

Continuous integration (CI) tools monitor pull requests, and help us identify build and code quality issues.

The results of the CI tests will show on your pull request.

By clicking on Details you can further zoom in; in case of a failure it will show you why it failed.

In case of success it will report how awesome you were.

### Are there any development docs?

There is no single source for OpenTTD development docs. It's a complex project with a long history, and multiple APIs.

A good entry point is [Development](https://wiki.openttd.org/en/Development/) on the OpenTTD wiki; this provides links to wiki documentation and other sources.

The GitHub repo also includes some non-comprehensive documentation in [/docs](./docs).

You may also want the guide to [compiling OpenTTD](./COMPILING.md).