Welcome to the Newcomers’ Guide!

DO NOT WORK ON ANY ISSUE WITHOUT ASSIGNMENT! If you do, someone else might work on it as well, and we might have no choice but to reject one of your Pull Requests. We hate it if someone’s time is wasted. For your own sake, please follow this guide. We put a lot of work into this for you!

Everyone in the coala community is expected to follow our Code of Conduct.

To become part of the coala developers team, there are a few steps you need to complete. The newcomer process is as follows:

You will start as a newcomer, which is kind of a trial. If you complete the following tasks, you will become a developer at coala:

  • run coala on a project of yours
  • merge a difficulty/newcomer Pull Request
  • review at least a difficulty/newcomer Pull Request
  • merge a difficulty/low Pull Request
  • review at least a difficulty/low or higher Pull Request

Note: After you have solved a difficulty/newcomer issue, please don’t take up any more. Instead, move on to more difficult issues.

Once you’ve run coala on a project, please fill out our usability survey. And once you’ve got your first Pull Request merged successfully, fill out our survey form. By doing so, you can help us make your experience better!

Once you’ve completed all five tasks, please fill our promotion request form to get promoted to the role of developer. GitLab contributions also count to the promotion of a newcomer to developer.


Don’t just fix a newcomer issue! Supervising newcomers is really a lot of work. We’re all volunteers and we can’t keep this up if you don’t help us in other areas as well!

Of course, the order of the steps above is not important, although we recommend that you start with a newcomer issue, end with a low issue, and review other PRs in the meantime!

This is a step-based guide that will help you make your first contribution to coala, while getting you familiar with the workflow!

For more information about Pull Requests, keep reading!


You do not need to read the coala codebase to get started - this guide is intended to help you do that without reading tons of meaningless code. Nobody is good at that.

Most importantly, this guide is not intended to “check if you are fit” to contribute, but is rather a crash course to make you fit to contribute. We are a bit picky when it comes to code quality, but it’s actually not at all hard to get to this level if you bear with us through this guide.

Step 0. Run coala

As you prepare to join our community, you should find out what this project is about - if you didn’t do this already. We highly recommend you install coala and use it on at least one of your projects. Also, we recommend that you read our development setup notes to learn how to set up an environment to work on coala.

Most importantly, keep notes on what could be changed to make coala usage easier! What documentation was missing? What was hard to understand?

See also

Struggling with this? We have a very verbose guide on this topic in our Google Code In resources which can help you find a suitable repository and run coala on a bigger project.

Once you complete this, please take the time to fill out this form so we can get better!

Step 1. Meet the Community and Get an Invitation to the Organization

To get started, the first step is to meet the community. We use gitter to communicate, and there the helpful community will guide you. Gitter is an instant messaging service used by developers and users of GitHub. Gitter uses chatrooms, where developers can join in and can talk about a particular topic. coala has 2 types of chatrooms - repository chatrooms and discussion topics. Repository chatrooms are related to a specific repository and discussion chatrooms are related to general discussion topics like conferences, workshops, etc.

  • coala This is the main chatroom and repository chatroom of coala/coala.
  • gsoc This is where you discuss about Google Summer of Code.
  • coala-bears Repo chatroom for coala/coala-bears.
  • workshop Discussions related to workshops go here.
  • conferences Everything related to conferences.
  • offtopic Anything fun! Our gaming sessions start here.

The list of all available chatrooms are available here - channel list

But before joining the community, here are few things that you should keep in mind.

  • Only log into Gitter using your GitHub account and not your Twitter account since the Gitter bot corobo identifies each user from their GitHub username which makes it possible to automate certain tasks such as asking the bot to assign an issue to your profile.
  • Don’t @-mention or private message people, unless its utterly important. @ mentions generate notifications on the various gitter clients the user may be signed into, you might even wake someone on the other side of the world up. Also it discourages other people to answer the question, so you might wait longer for an answer.
  • Do not mention users unrelated to a particular issue/question. This also means you should not mention the person that was last online. For example, mentioning someone on a Github issue will subscribe them to that issue, even if they don’t want to be a part of the discussion. However, mentioning someone is okay if they really need to see your message.
  • Don’t use /all if you are a newcomer or do not have a critical reason.
  • Don’t repeatedly @-mention people in an ongoing conversation.
  • You should ask someone before mentioning them.

Now you are ready to join coala community at coala gitter. The newcomers should ping us “Hello World” to let us know they are here because we care!

When you say “Hello World” in chat corobo (our gitter bot) will invite you to be part of the Newcomer team. The invitation will be sent by mail and you will have to accept it to join. If you don’t find the invitation, accept it here.

Congratulations! Now that you are part of our organization, you can start working on issues. If you are familiar with git, you can skip the next section and pick an issue.


If you have any questions, ask them in a precise and respectful way that maximizes your chances of getting the answer you’re looking for. If you’re unsure how to do that, please read: How To Ask Questions The Smart Way.

Optional. Get Help With Git

We use GitHub to manage our repository. If you’re not familiar with git/GitHub, we strongly recommend following a tutorial, such as this one.

We also have a page dedicated to git commands that will help you learn the basics.


You can view some of our repositories on GitLab. For more information about it, browse to our wiki page.

If anything is unclear, or you are encountering problems, feel free to contact us on gitter, and we will help you!

Step 2. Picking Up an Issue

Now it is time to pick an issue. It is the best way to familiarise yourself with the codebase. You can view all Newcomer issues on GitHub.


You need to be logged in before you follow the Newcomer issues link.

See also

For more information about what bears are, please check the following link: Writing Native bears

The easy issues that will help you get started are labeled as difficulty/newcomer and are only there to give you a glimpse of what it’s like to work with us and what the workflow is like.

Now pick an issue which isn’t assigned and which you would like to fix. Leave a comment that you would like to be assigned to the issue. This way we don’t have multiple people working on the same issue at the same time. Now you can start working on it!


As stated above, you should never work on an issue without being assigned. Fortunately, corobo is here to help you! If you are interested in picking up an issue, just write the following command in gitter chat:

corobo assign <issue_link>

Be sure to copy the full link to the issue! Also take up the issue, only when you know what the problem is and how to solve it.

You can do amazing stuff using corobo.

  • Issue assigning as stated earlier.

  • File issues:

    corobo file issue <repo> <title>
  • You shouldn’t close any PR, instead mark them as work in progress:

    corobo mark wip <full url>
  • To label a PR as pending review:

    corobo mark pending <full url>
  • To see all of the corobo commands:

    corobo help

Before starting your first commit, check out this link: Writing good commits.


An important part of working on issues is documenting your work in such a way that it is easy for others to read and understand. A lot of Newcomer issues involve improving documentation.

  • For more information about writing good documentation, please check the following link: Writing Documentation
  • For more information about how to style Python code according to the PEP8 code style convention, please check the following link: PEP8 Style Guide for Python code

Step 3. Creating a Fork and Testing Your Changes

This tutorial assumes you are working on your own fork. To fork the repository, go to the official repository of coala/coala-bears and click on the Fork button from the website interface. To add it locally, simply run:

$ git remote add myfork fork_link

where myfork is the name of your fork, and fork_link is a link to your fork repository.


It is important that you DO NOT make your changes on the master branch of your forked repository to avoid the following cases:

  • If you make a rebase to synchronize your repository to the original, every commit that is pushed to the remote master will be pulled in your master branch. Then if you make a pull request to commit your changes to the remote, the commits that got synced from the rebase will be recommitted along with your work in the pull request.
  • You cannot have two pull requests using the same branch name. Therefore, if your fork’s master has been used in a pull request and you decide to work on a different issue you will have to branch eventually. Differently every new commit that you make on your master branch will get attached to the initial pull request and that will result in altering the purpose of that request.
  • If your fork’s master has been used in a pull request, you have to keep the change in the branch until that get’s merged to the remote master. That will lead to the complications listed above, if you decide to work on a different issue.

In order to avoid the above mentioned cases you can create a new branch where you will work on the issue. To do that run:

$ git checkout -b <branchname>

Now you need to make sure your change is actually working. For this, you will need to test it locally before pushing it to your fork and checking it with concrete examples. The first time, you will need to install some requirements. This can be done by executing the following command while in the root of the coala project directory:

$ pip3 install -r test-requirements.txt -r requirements.txt

After that, you can run coala by simply typing

$ coala

into your bash prompt. This will analyze your code and help you fix it.

See also

Executing tests

Step 4. Sending Your Changes


Before committing your changes, please check that you are indeed in a development branch created in step 3. To check if you are in a branch, type:

$ git branch

Your current branch will have an asterisk (*) next to it. Ensure that there is no asterisk next to the master branch.

Now that you’ve fixed the issue, you’ve tested it, and you think it is ready to be merged, create a commit and push it to your fork, using:

$ git push -u myfork <branchname>

where myfork is the name of your fork that you added at the previous step.


You can also add a profile picture to your Github account so that you can stand out from the crowd!

Step 5. Creating a Pull Request

Now that your commit has been sent to your fork, it is time to create a Pull Request. You can do this by accessing your fork on GitHub and clicking New Pull Request.

Congratulations! You have now created your first Pull Request!


Do not delete your comments on Github, because that makes it hard for other developers to follow that issue. If there is a typo or a task list to be updated, you can edit your comment instead. If you need to add new information, make a new comment.

If you know you have more work to do on this Pull Request before it is ready to be accepted, you can indicate this to other developers by starting your Pull Request title with wip (case-insensitive, stands for “Work in Progress”).

Step 6. Waiting for Review

After creating a Pull Request, your PR moves to the review process (all will be explained in the next step), and all you can do is wait. The best thing you can do at this step is review other people’s PRs. Not only will this help the maintainers with the workload, but this is one of the three core steps towards becoming a full-blown coalaian. Never close a Pull Request unless you are told to do so.

For more information about reviewing code, check out this link.


Reviewing code helps you to learn from other people’s mistakes so you can avoid making those same mistakes yourself in the future! Thus, you are improving yourself in the process.

We highly encourage you to do reviews. Don’t be afraid of doing something wrong - there will always be someone looking over it before merging it to master.

Step 7. Review Process

After creating your Pull Request, it enters the review process. You can see that’s the case from the process/pending review label. Now all you have to do is wait, or let the other developers know on Gitter that you have published your changes.


Do not tag the reviewers every time you push a change. They review PRs consistently whenever they have time!

Now there are two possibilities:

  • your Pull Request gets accepted, and your commits will get merged into the master branch
  • your Pull Request doesn’t get accepted, and therefore you will need to modify it as per the review comments


Wait until the reviewer has reviewed your whole Pull Request and has labeled it process/wip. If you push again before that happens, and their comments disappear, it can be considered rude.


You might be wondering what those CI things on your Pull Request are. For more detailed info about them, see this page.

It’s highly unlikely that your Pull Request will be accepted on the first attempt - but don’t worry, that’s just how it works. It helps us keep coala clean and stable.

See also

Review Process.

Now, if you need to modify your code, you can simply edit it again, add it, and commit it using

$ git commit -a --amend

This will edit your last commit message. If your commit message was considered acceptable by our reviewers, you can simply send it again (without any changes). If not, edit it and send it. You have successfully edited your last commit!


Don’t forget! After editing your commit, you will have to push it again. This can be done using:

$ git push --force myfork

The meaning of myfork is explained in step 3 of this guide. The Pull Request will automatically update with the newest changes.

Congratulations! Your PR just got accepted! You’re awesome. Now you should tell us about your experience and go for a low issue - they are really rewarding!


Do not delete the fork subsequent to Pull Request for review or after it is merged!


Do not just fix a newcomer issue! It is highly recommended that you fix one newcomer issue to get familiar with the workflow at coala and then proceed to a difficulty/low issue.

However, those who are familiar with opensource projects can start with difficulty/low issues.

We highly encourage you to start reviewing other’s issues after you complete your newcomer issue, as reviewing helps you to learn more about coala and python.


If you need help picking up an issue, you can always ask us. The community is extremely helpful, so don’t ask to ask, just ask.

If you ever have problems in finding links, you may find the solution in our useful links section.