rebar3/CONTRIBUTING.md

Contributing to rebar

Before implementing a new feature, please submit a ticket to discuss your plans. The feature might have been rejected already, or the implementation might already be decided.

See Community and Resources.

Code style

The following rules must be followed:

• Do not introduce trailing whitespace
• Do not mix spaces and tabs
• Do not introduce lines longer than 80 characters

The following rules should be followed:

• Write small functions whenever possible
• Avoid having too many clauses containing clauses containing clauses. Basically, avoid deeply nested functions.

erlang-mode (emacs) indentation is preferred. This will keep the code base consistent. vi users are encouraged to give Vim emulation (more info) a try.

Pull requests and branching

Use one topic branch per pull request. If you do that, you can add extra commits or fix up buggy commits via git rebase -i, and update the branch. The updated branch will be visible in the same pull request. Therefore, you should not open a new pull request when you have to fix your changes.

Do not commit to master in your fork.

Provide a clean branch without merge commits.

Tests

As a general rule, any behavioral change to rebar requires a test to go with it. If there's already a test case, you may have to modify that one. If there isn't a test case or a test suite, add a new test case or suite in test/.

$ ./bootstrap
$ ./rebar3 ct

Credit

To give everyone proper credit in addition to the git history, please feel free to append your name to THANKS in your first contribution.

Committing your changes

Please ensure that all commits pass all tests, and do not have extra Dialyzer warnings. To do that run ./rebar3 ct and ./rebar3 as dialyze dialyzer.

Structuring your commits

Fixing a bug is one commit. Adding a feature is one commit. Adding two features is two commits. Two unrelated changes is two commits.

If you fix a (buggy) commit, squash (git rebase -i) the changes as a fixup commit into the original commit.

Writing Commit Messages

It's important to write a proper commit title and description. The commit title must be at most 50 characters; it is the first line of the commit text. The second line of the commit text must be left blank. The third line and beyond is the commit message. You should write a commit message. If you do, wrap all lines at 72 characters. You should explain what the commit does, what references you used, and any other information that helps understanding your changes.

Basically, structure your commit message like this:

One line summary (at most 50 characters)

Longer description (wrap at 72 characters)

Commit title/summary

• At most 50 characters
• What was changed
• Imperative present tense (Fix, Add, Change)
• Fix bug 123
• Add 'foobar' command
• Change default timeout to 123
• No period

Commit description

• Wrap at 72 characters
• Why, explain intention and implementation approach
• Present tense