jar task blows up when *print-length* is set

[borkdude]

Steps to reproduce:

• Clone https://github.com/borkdude/lein2boot.git
• Uncomment the line (alter-var-root (var *print-length*) (fn [v] 20))
• Run boot build

[alandipert]

This is tricky because multiple instances of the Clojure runtime (pods) are floating around the JVM in any given boot project.

So, it's not really possible in a build.boot to set a Clojure runtime variable that all other instances of Clojure will automatically see.

There is a mechanism for running code in every pod created by boot before it's returned to any task or user code. You can create a file called boot-shim.clj and add forms to run in clojure.core. For instance, could create a boot-shim.clj with this content:

(def ^:dynamic *print-length* 20)

Is the reason you want to set the print length so that the REPL user won't have to do it manually?

If so, another, more straightforward way of achieving your goal might be with task-options!:

(task-options!
 repl {:init-ns 'animals.server
       :eval '(set! *print-length* 20)})

[borkdude]

Yeah, mainly REPL. Thanks! Just in time for my blogpost!