Chapter 14. Compatibility with other build tools tries its best to be compatible with the other Erlang build tools. It can use dependencies written with other build tools in mind, and can also make your projects usable by those build tools as well. is like the cool kid that gets along with everybody.

In this chapter I will use the term Rebar project to refer to a project built using Rebar 2, Rebar 3 or Mad. These three build tools are very similar and share the same configuration file.

14.1. Rebar projects as dependencies comes with a feature called Autoload which will use Rebar 2 to patch any Rebar project and make it compatible with This feature essentially patches Rebar out and adds a Makefile to the project that can then use for building:

Autoload is documented in more details in the Packages and dependencies chapter.

14.2. projects as Rebar dependencies projects can be made compatible with the Rebar family of build tools pretty easily, as will generate all the files they require for building.

The Rebar family requires two files: a rebar.config file containing compilation options and the list of dependencies, and the application resource file, found either at ebin/$(PROJECT).app or at src/$(PROJECT).app.src.

14.2.1. Rebar configuration comes with a target that generates a rebar.config file when invoked:

$ make rebar.config

Careful! This will build the file even if it already existed before.

To build this file, uses information it finds in the DEPS and ERLC_OPTS variables, among others. This means that the Rebar family builds your project much the same way as

Careful though! Different build tools have different fetching strategies. If some applications provide differing dependencies, they might be fetched differently by other build tools. Check the upcoming Sanity check chapter to find out how to detect such issues.

You can automatically generate this file when you build your application, by making it a dependency of the app target:

app:: rebar.config

Don’t forget to commit the file when it changes!

If you run into other issues, it’s probably because you use a feature specific to, like the cp fetch method. It could also be that we forgot to handle something! Sorry. We are of course interested to hear about any compatibility problems you may have, just open a ticket!

14.2.2. Application resource file has two ways to generate an application resource file: from the information found in the Makefile, or from the information found in the src/$(PROJECT).app.src file. Needless to say, if you have this file in your repository, then you don’t need to worry about compatibility with other build tools.

If you don’t, however, it’s not much harder. Every time will compile your application, it will produce a new ebin/$(PROJECT).app file. Simply commit this file when it changes. It will only change when you modify the configuration, add or remove modules.