CONTRIBUTING.md

Contributing

The Carpentries (Software Carpentry, Data Carpentry, and Library Carpentry) are open source projects, and we welcome contributions of all kinds: new lessons, fixes to existing material, bug reports, and reviews of proposed changes are all welcome.

Contributor Agreement

By contributing, you agree that we may redistribute your work under our license. In exchange, we will address your issues and/or assess your change proposal as promptly as we can, and help you become a member of our community. Everyone involved in The Carpentries agrees to abide by our code of conduct.

Who Should Contribute?

Contributions to this lesson are welcome from anyone with an interest in the project.

How to Contribute

The easiest way to get started is to file an issue to tell us about a spelling mistake, some awkward wording, or a factual error. This is a good way to introduce yourself and to meet some of our community members.

1. If you do not have a GitHub account, you can send us comments by email. However, we will be able to respond more quickly if you use one of the other methods described below.

2. If you have a GitHub account, or are willing to create one, but do not know how to use Git, you can report problems or suggest improvements by creating an issue. This allows us to assign the item to someone and to respond to it in a threaded discussion.

3. If you are comfortable with Git, and would like to add or change material, you can submit a pull request (PR). Instructions for doing this are included below.

Note: if you want to build the website locally, please refer to The Workbench documentation.

Where to Contribute

1. If you wish to change this lesson, add issues and pull requests here.
2. If you wish to change the template used for workshop websites, please refer to The Workbench documentation.

What to Contribute (General)

There are many ways to contribute, from writing new exercises and improving existing ones to updating or filling in the documentation and submitting bug reports about things that do not work, are not clear, or are missing. If you are looking for ideas, please see the list of issues for this repository, or the issues for Data Carpentry, Library Carpentry, and Software Carpentry projects.

Comments on issues and reviews of pull requests are just as welcome: we are smarter together than we are on our own. Reviews from novices and newcomers are particularly valuable: it's easy for people who have been using these lessons for a while to forget how impenetrable some of this material can be, so fresh eyes are always welcome.

What to Contribute (This Lesson)

Any contributions are welcome, particularly ideas for how the existing content could be improved or updated, and/or errors that need to be corrected. Comments on existing issues and reviews of pull requests are similarly welcome.

If you plan to submit a pull request, please open an issue (or comment on an existing thread) first to ensure that effort is not duplicated or spent making a change that will not be accepted by the Maintainers.

Content / style guidelines

• If you add an image / figure that was generated from Python code, please include this code in your PR under episodes/fig/source.

• If you add a new image or figure, verify that it displays correctly in the lesson’s dark mode. A color-inversion filter is applied by Varnish to all images by default in dark mode, which may cause some images to appear incorrectly or become unreadable. If your image is affected, include an additional version of the same image with a -dark suffix in its filename.

• Use the terms in the table below, when referring to Python libraries within the lesson. The table gives two terms for each library: Term for descriptive text which should be used when discussing the library in plain English / full sentences and Term for code which should be used when referring to code (and within code).

  Python library	Term for descriptive text	Term for code
  scikit-image	scikit-image	skimage
  NumPy	NumPy	numpy
  Matplotlib	Matplotlib	matplotlib
  imageio	imageio	imageio

• When importing scikit-image use:

  import skimage as ski

  Therefore, to access specific functions, you need to use their submodule name. For example:

  import skimage as ski
  
  rr, cc = ski.draw.rectangle(start=(357, 44), end=(740, 720))

• For reading and writing images, use the imageio library and avoid use of skimage.io. For example:

  import imageio.v3 as iio
  
  chair = iio.imread(uri="data/chair.jpg")  # read an image
  iio.imwrite(uri="data/chair.tif", image=chair)  # write an image

• Comments providing an overall description of a code snippet should use triple quotes """, e.g.,

  """Python script to load a colour image in grayscale"""
  
  chair = iio.imread(uri="data/chair.jpg")
  gray_chair = ski.color.rgb2gray(chair)

What Not to Contribute (General)

Our lessons already contain more material than we can cover in a typical workshop, so we are usually not looking for more concepts or tools to add to them. As a rule, if you want to introduce a new idea, you must (a) estimate how long it will take to teach and (b) explain what you would take out to make room for it. The first encourages contributors to be honest about requirements; the second, to think hard about priorities.

We are also not looking for exercises or other material that only run on one platform. Our workshops typically contain a mixture of Windows, macOS, and Linux users; in order to be usable, our lessons must run equally well on all three.

What Not to Contribute (This Lesson)

Although most contributions will be welcome at this stage of the curriculum's development, the time available to deliver the content in a training event is strictly limited and needs to be accounted for when considering the addition of any new content. If you want to suggest the addition of new content, especially whole new sections or episodes, please open an issue to discuss this with the Maintainers first and provide the following information alongside a summary of the content to be added:

1. A suggested location for the new content.
2. An estimate of how much time you estimate the new content would require in training (teaching + exercises).
3. The learning objective(s) of this new content.
4. (optional, but strongly preferred) A suggestion of which of the currently-used learning objectives could be removed from the curriculum to make space for the new content.

Using GitHub

If you choose to contribute via GitHub, you may want to look at How to Contribute to an Open Source Project on GitHub. In brief, we use GitHub flow to manage changes:

1. Create a new branch in your desktop copy of this repository for each significant change.
2. Commit the change in that branch.
3. Push that branch to your fork of this repository on GitHub.
4. Submit a pull request from that branch to the upstream repository.
5. If you receive feedback, make changes on your desktop and push to your branch on GitHub: the pull request will update automatically.

NB: The published copy of the lesson is usually in the main branch.

Each lesson has a team of maintainers who review issues and pull requests or encourage others to do so. The maintainers are community volunteers, and have final say over what gets merged into the lesson.

Merging Policy

Pull requests made to the default branch of this repository (from which the lesson site is built) can only be merged after at least one approving review from a Maintainer. Any Maintainer can merge a pull request that has received at least one approval, but they may prefer to wait for further input from others before merging.

Other Resources

The Carpentries is a global organisation with volunteers and learners all over the world. We share values of inclusivity and a passion for sharing knowledge, teaching and learning. There are several ways to connect with The Carpentries community listed at https://carpentries.org/connect/ including via social media, slack, newsletters, and email lists. You can also reach us by email.