rebar3/README.md

rebar
=====

rebar is an Erlang build tool that makes it easy to compile and  
test Erlang applications, port drivers and releases.

[![Build Status](https://secure.travis-ci.org/basho/rebar.png?branch=master)](http://travis-ci.org/basho/rebar)

rebar is a self-contained Erlang script, so it's easy to distribute or even  
embed directly in a project. Where possible, rebar uses standard Erlang/OTP  
conventions for project structures, thus minimizing the amount of build  
configuration work. rebar also provides dependency management, enabling  
application writers to easily re-use common libraries from a variety of  
locations (git, hg, etc).

Building
--------

Information on building and installing [Erlang/OTP](http://www.erlang.org)
can be found [here](https://github.com/erlang/otp/wiki/Installation)
([more info](https://github.com/erlang/otp/blob/master/INSTALL.md)).

### Dependencies

To build rebar you will need a working installation of Erlang R13B03 (or
later).

Should you want to clone the rebar repository, you will also require git.

#### Downloading

You can download a pre-built binary version of rebar from:

https://github.com/basho/rebar/wiki/rebar

#### Building rebar

```sh
$ git clone git://github.com/basho/rebar.git
$ cd rebar
$ ./bootstrap
Recompile: src/getopt
...
Recompile: src/rebar_utils
==> rebar (compile)
Congratulations! You now have a self-contained script called "rebar" in
your current working directory. Place this script anywhere in your path
and you can use rebar to build OTP-compliant apps.
```


Contributing to rebar
=====================

Pull requests and branching
---------------------------

Use one topic branch per pull request.

Do not commit to master in your fork.

Provide a clean branch without any merge commits from upstream.

Usually you should squash any intermediate commits into the original single commit.

Code style
----------

Do not introduce trailing whitespace.

Do not mix spaces and tabs.

Do not introduce lines longer than 80 characters.

[erlang-mode (emacs)](http://www.erlang.org/doc/man/erlang.el.html) indentation is preferred.
vi-only users are encouraged to   
give [Vim emulation](http://emacswiki.org/emacs/Evil) ([more info](https://gitorious.org/evil/pages/Home)) a try.

Writing Commit Messages
-----------------------

Structure your commit message like this:

<pre>
One line summary (less than 50 characters)

Longer description (wrap at 72 characters)
</pre>

### Summary

* Less than 50 characters
* What was changed
* Imperative present tense (fix, add, change)
  * `Fix bug 123`
  * `Add 'foobar' command`
  * `Change default timeout to 123`
* No period

### Description

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

### Atomicity

* Break up logical changes
* Make whitespace changes separately

Run checks
----------

Before you submit a patch, run ``make check`` to execute
the test suite and check for  
[xref](http://www.erlang.org/doc/man/xref.html) and
[Dialyzer](http://www.erlang.org/doc/man/dialyzer.html)
warnings. You may have to run ``make clean`` first.

[Dialyzer](http://www.erlang.org/doc/man/dialyzer.html) warnings are compared
against a set of safe-to-ignore warnings found in  
[dialyzer_reference](https://raw.github.com/basho/rebar/master/dialyzer_reference).
[xref](http://www.erlang.org/doc/man/xref.html) is run with
[custom queries](https://raw.github.com/basho/rebar/master/rebar.config)
to suppress safe-to-ignore warnings.

It is **strongly recommended** to check the code with
[Tidier](http://tidier.softlab.ntua.gr:20000/tidier/getstarted).
Select all transformation   
options and enable **automatic** transformation. If Tidier suggests a transformation,  
apply the changes **manually** to the source code. Do not use the code from
the  
tarball (*out.tgz*) as it will have white-space changes applied by Erlang's pretty-printer.

Community and Resources
-----------------------

In case of problems that cannot be solved through documentation or examples, you may  
want to try to contact members of the community for help. The community is also where  
you want to go for questions about how to extend rebar, fill in bug reports, and so on.

The main place to go for questions is the [rebar mailing list](http://lists.basho.com/pipermail/rebar_lists.basho.com/). If you need quick feedback,  
you can try the #rebar channel on [irc.freenode.net](http://freenode.net). Be sure to check the [wiki](https://github.com/basho/rebar/wiki) first,  
just to be sure you're not asking about things with well known answers.

For bug reports, roadmaps, and issues, visit the [github issues page](https://github.com/basho/rebar/issues).

General rebar community resources and links:

- [Rebar Mailing List](http://lists.basho.com/pipermail/rebar_lists.basho.com/)
- #rebar on [irc.freenode.net](http://freenode.net/)
- [wiki](https://github.com/basho/rebar/wiki)
- [issues](https://github.com/basho/rebar/issues)