Checkout dependencies can be used to add another work-in-progress project to your Leiningen project during development (for example: you're developing an app and underlying library in parallel).
However, when a checkout dependency itself has a "traditional" dependency (from Clojars), running lein run in the parent project will throw a java.io.FileNotFoundException since it apparently does not retrieve the "traditional" dependencies of its checkout dependencies.
Is there a way to let a Leiningen project recursively download the dependencies of its checkout dependencies?
My opinion of the "proper" way to do this is to have your project depend on the library in your checkouts directory as a traditional dependency in addition to having it in your checkouts directory.
Then every time you change dependencies, run lein install in your library project. This will cause lein to generate the appropriate jar file and install it into your local maven repo. It does not matter if this library project is finished, because you are not actually running it in this state, just using it to fetch dependencies.
Then when it does work you don't have to do anything to "switch to production" other than remove your checkouts directory. The dependency is already in place in the dependent project.
There is a side effect of using checkouts to work on libraries in that the code is loaded twice. Once from the "depended on" version, and then again from the "checkouts version". This is very occationally a problem for me when I'm using protocols and have to remember to re-load the protocol definition.