Hacking on cider-nrepl

Hacking on cider-nrepl requires nothing but a bit of knowledge of Clojure and nREPL. In this section we’ll take a look at some practical tips to make you more productive while working on the project.


cider-nrepl has some pretty complicated Lein profiles, as it has to deal with multiple versions of Clojure and ClojureScript, plus dependency inlining with Mr. Anderson. That’s why we’ve added a good old Makefile to save you the trouble of having to think about the profiles and just focus on the tasks at hand.

Obviously you can still work with Lein directly, but you won’t have to do this most of the time.

Testing your changes

You’ve got several options for doing this:

  • Installing a snapshot of your work recently and doing tests against it (e.g. with make install).

  • Relying solely on the unit tests. You better write good unit tests, though!

  • Spinning new versions of nREPL from the REPL, and connecting some client to them to test your changes.

  • If you’re already using a client that depends on cider-nrepl (e.g. CIDER) making changes to the cider-nrepl code will normally result in those changes becoming immediately available to your client.

Running the tests

Just do:

$ make test

That’s going to handle the dependency inlining behind the scenes. By default the tests are going to be run against the most recent Clojure version that’s supported.


cider-nrepl uses eastwood and cljfmt. Make sure your changes conform to the project’s baseline by doing:

$ make eastwood
$ make cljfmt


Just do:

$ make deploy

This is going to handle the dependency inlining behind the scenes.