Want to contribute? Great! But first, please take a few minutes to read this document in full. Doing so upfront will minimize the turnaround time required to get your changes incorporated.
Before we can use your code, you must sign the Google Individual Contributor License Agreement, also known as the CLA, which you can easily do online. The CLA is necessary mainly because you own the copyright to your changes, even after your contribution becomes part of our codebase, so we need your permission to use and distribute your code. We also need to be sure of various other things--for instance that you will tell us if you know that your code infringes on other people's patents. You do not have to sign the CLA until after you have submitted your code for review and a member has approved it, but you must do it before we can put your code into our codebase.
Contributions made by corporations are covered by a different agreement than the one above: the Google Software Grant and Corporate Contributor License Agreement. Please get your company to sign this agreement instead if your contribution is on their behalf.
Unless you have a strong reason not to, please assign copyright of your changes to Google Inc. and use the 3-clause BSD license text included throughout the codebase (see LICENSE). Keeping the whole project owned by a single entity is important, particularly to avoid the problem of having to replicate potentially hundreds of different copyright notes in documentation materials, etc.
Before you start working on a larger contribution, you should get in touch with us first through the kyua-discuss mailing list with your idea so that we can help out and possibly guide you. Coordinating upfront makes it much easier to avoid frustration later on.
Subscribe to the kyua-log mailing list to get notifications on new commits, Travis CI results, or changes to bugs.
Always work on a non-master branch.
Make sure the history of your branch is clean. (Ab)use git rebase -i master
to ensure the sequence of commits you want pulled is easy to follow and that
every commit does one (and only one) thing. In particular, commits of the
form Fix previous or Fix build should never ever exist; merge those fixes
into the relevant commits so that the history is clean at pull time.
Always trigger Travis CI builds for your changes (hence why working on a branch is important). Push your branch to GitHub so that Travis CI picks it up and performs a build. If you have forked the repository, you may need to enable Travis CI builds on your end. Wait for a green result.
It is OK and expected for you to git push --force on non-master
branches. This is required if you need to go through the commit/test cycle
more than once for any given branch after you have "fixed-up" commits to
correct problems spotted in earlier builds.
Do not send pull requests that subsume other/older pull requests. Each major change being submitted belongs in a different pull request, which is trivial to achieve if you use one branch per change as requested in this workflow.
All changes will be subject to code reviews pre-merge time. In other words: all pull requests will be carefully inspected before being accepted and they will be returned to you with comments if there are issues to be fixed.
Be careful of stylistic errors in your code (see below for style guidelines). Style violations hinder the review process and distract from the actual code. By keeping your code clean of style issues upfront, you will speed up the review process and avoid frustration along the way.
Whenever you are ready to submit a pull request, review the combined diff
you are requesting to be pulled and look for issues. This is the diff that
will be subject to review, not necessarily the individual commits. You can
view this diff in GitHub at the bottom of the Open a pull request form that
appears when you click the button to file a pull request, or you can see the
diff by typing git diff <your-branch> master.
Follow standard Git commit message guidelines. The first line has a maximum length of 50 characters, does not terminate in a period, and has to summarize the whole commit. Then a blank line comes, and then multiple plain-text paragraphs provide details on the commit if necessary with a maximum length of 72-75 characters per line. Vim has syntax highlighting for Git commit messages and will let you know when you go above the maximum line lengths.
Use the imperative tense. Say Add foo-bar or Fix baz instead of Adding
blah, Adds bleh, or Added bloh.
All changes pushed to master should cross-reference one or more issues in
the bug tracker. This is particularly important for bug fixes, but also
applies to major feature improvements.
Unless you have a good reason to do otherwise, name your branch issue-N
where N is the number of the issue being fixed.
If the fix to the issue can be done in a single commit, terminate the commit
message with Fixes #N. where N is the number of the issue being fixed and
include a note in NEWS about the issue in the same commit. Such fixes can
be merged onto master using fast-forward (the default behavior of git
merge).
If the fix to the issue requires more than one commit, do not include
Fixes #N. in any of the individual commit messages of the branch nor include
any changes to the NEWS file in those commits. These "announcement" changes
belong in the merge commit onto master, which is done by git merge --no-ff
--no-commit your-branch, followed by an edit of NEWS, and terminated with a
git commit -a with the proper note on the bug being fixed.
These notes are generic and certainly non-exhaustive:
Respect formatting of existing files. Note where braces are placed, number of blank lines between code chunks, how continuation lines are indented, how docstrings are typed, etc.
Indentation is always done using spaces, not tabs. The only exception is in
Makefiles, where any continuation line within a target must be prefixed by a
single tab.
Be mindful of spelling and grammar. Mistakes of this kind are enough of a reason to return a pull request.
Use proper punctuation for all sentences. Always start with a capital letter and terminate with a period.
Respect lexicographical sorting wherever possible.
Lines must not be over 80 characters.
No trailing whitespace.
Two spaces after end-of-sentence periods.
Two blank lines between functions. If there are two blank lines among code blocks, they usually exist for a reason: keep them.
In C++ code, prefix all C identifiers (those coming from extern "C"
includes) with ::.