We value all kinds of contributions, not just actual code. Maybe the easiest and yet very good way of helping us improve swave is to ask questions, voice concerns or propose improvements on the Mailing List.

Or simply tell us about you or your organization using swave by sending us a small statement for the References page.

If you do like to contribute actual code in the form of bug fixes, new features or other patches this page gives you more info on how to do it.

Cooperation Process

swave follows the Collective Code Construction Contract (C4), which is an evolution of the Fork + Pull Model, aimed at providing an optimal collaboration model for free software projects.

This process was originally designed by the late @hintjens for the ZeroMQ community where it has worked exceptionally well for many years. It has these goals (quote from C4 specification):

  1. To maximize the scale and diversity of the community around a project, by reducing the friction for new Contributors and creating a scaled participation model with strong positive feedbacks;

  2. To relieve dependencies on key individuals by separating different skill sets so that there is a larger pool of competence in any required domain;

  3. To allow the project to develop faster and more accurately, by increasing the diversity of the decision making process;

  4. To support the natural life cycle of project versions from experimental through to stable, by allowing safe experimentation, rapid failure, and isolation of stable code;

  5. To reduce the internal complexity of project repositories, thus making it easier for Contributors to participate and reducing the scope for error;

  6. To enforce collective ownership of the project, which increases economic incentive to Contributors and reduces the risk of hijack by hostile entities.

If you’d like to participate in the development of swave you are very much invited to check out the C4 specification as well as the background information available here. We are looking forward to receiving your first pull request!

Building swave

Since swave is open-source and hosted on github you can easily build it yourself.

Here is how:

  1. Install SBT. You can see the SBT version that swave is currently built with here.

  2. Check out the swave source code from the github repository. Pick the master branch for the most current state or a tagged commit for a specific version.

  3. Run sbt compile test to compile the suite and run all tests.

Contributing/Fixing Documentation

The site, i.e. what you see here at, is built with paradox, a static site generator. It converts the markdown documentation living in the docs sub-project into static HTML. If you want to contribute documentation (which we always welcome very much!) try this process for quickly seeing how your changes affect the look of the site:

  • Follow the instructions in the above section on “Building swave

  • Start sbt

  • In the sbt shell run project docs to change into the docs project

  • Run makeSite to build the site for the first time (which might take some time)

  • Run openSite to open a browser on the index.html file of the directory the site was produced to

  • Run ~makeSite to let SBT monitor changes to the documentation sources and rebuild the site automatically

  • Edit the documentation files inside the docs/src/paradox subdirectory. After saving a file SBT will automatically regenerate the site and you can reload the page in the browser to see your changes.

Issue Tracking

The swave team uses the Issues Page of the projects github repository for issue management. If you find a bug and would like to report it please go there and create an issue.

If you are unsure, whether the problem you’ve found really is a bug please ask on the Mailing List first.

GIT Branching Model

The swave team follows the “standard” practice of using the master branch as main integration branch, with WIP- and feature branches branching of it. The rule is to keep the master branch always “in good shape”, i.e. having it compile and test cleanly.

Additionally we might maintain release branches for older and possibly future releases.

GIT Commit Messages

We try to follow the imperative present tense style for commit messages and additionally prefix each message with some simple meta data that make it easier to see

  • how the public API is affected by the commit
  • what sub-project(s) the commit mainly affects
  • which ticket the commit is associated with

Here are three exemplary (and made-up) commit messages to illustrate the concept:

=tsk #123 fix incorrect display of unterminated output state

+cor #234 add `takeWithin` transformation

!cak,csc #345 clean up package structure

Following this naming pattern for all commits (except for merges, which start with “Merge”) is extremely helpful when looking at the commit history. Also, it makes the generation of CHANGELOG entries and release notes much easier.

API Effect Category

The first character classifies the effect of the commit on the public swave API that we try to keep as stable as possible. Requiring this marker makes sure that the committer has actively thought about the effects of the commit on the public API. There are three categories:

Marker Category Description
= Neutral Only touches things “under the hood” and has no effect on swave’s public API.
+ Extending Extends the API by adding things. In rare cases this might break code due to things like identifier shadowing but is generally considered a “safe” change.
! Breaking Changes or removes public API elements. Will definitely break user code relying on these parts of the API surface.

Note that apart from the actual Scala interfaces the public API surface covered by these categories also includes configuration settings (most importantly the reference.conf files).

Project Identifier(s)

Immediately after the initial “API Effect Category Marker” we list all sub-projects touched by the commit (in decreasing order of “affectedness” and separated by a simple comma without spaces). In order to keep things concise the projects are identified with these simple 3-letter abbreviations:

Sub-Project Abbreviation
core cor
core-macros cor
core-tests cor
compat-akka cak
compat-scodec csc
docs doc
testkit tkt
benchmarks bmk
sbt project pro

Ticket Number

The Collective Code Construction Contract (C4) mandates that all changes should happen in the context of a certain ticket / github issue. By putting the number of the ticket into the commit message GitHub can associate the commit with the ticket and list it on the ticket’s GitHub page.

Also, having all commits display their ticket number makes it much easier to understand the project history and compile the release notes and the CHANGELOG.