How to display classpath used for run task? - sbt

Question

How can the classpath used for run task be displayed under SBT 0.13?
I have found some info here https://groups.google.com/forum/#!msg/simple-build-tool/0rhVRPnjyZU/DOYAd14gh1wJ:
I was dumping my classpaths as a way to troubleshoot my build recently and maybe this task can help you too:
lazy val printClasspath = task {
this.runClasspath.getPaths.foreach(println);
None
}
runClasspath is a PathFinder [1] instance and you can interrogate it even further. I guess building a ':'-separated list of those paths will be easy.
I don't understand where and how I should use this tip. Please advise.

Answer 1

If I type this in the sbt shell:
inspect run
I see, among other output:
[info] Dependencies:
[info] runtime:fullClasspath
So then if I type:
show runtime:fullClasspath
I get output like:
List(
Attributed(/Users/tisue/Dropbox/repos/euler/target/scala-2.10/classes),
Attributed(/Users/tisue/.sbt/boot/scala-2.10.3/lib/scala-library.jar))
Which is probably what you were looking for?
You can also get it in a colon-separated form suitable for use with java -classpath on the command line:
export runtime:fullClasspath
which prints e.g.:
/Users/tisue/Dropbox/repos/euler/target/scala-2.10/classes:/Users/tisue/.sbt/boot/scala-2.10.3/lib/scala-library.jar

Answer 2

tl;dr Use last run or write a custom task.
last run
With last run you should be presented with the entire classpath:
[info] Running main.Main
[debug] Waiting for threads to exit or System.exit to be called.
[debug] Classpath:
[debug] /Users/jacek/work/ingrifo/dictionary-spray/target/scala-2.11/classes
[debug] /Users/jacek/.ivy2/cache/org.scala-lang/scala-library/jars/scala-library-2.11.4.jar
[debug] /Users/jacek/.ivy2/cache/io.spray/spray-can_2.11/bundles/spray-can_2.11-1.3.2.jar
[debug] /Users/jacek/.ivy2/cache/io.spray/spray-io_2.11/bundles/spray-io_2.11-1.3.2.jar
[debug] /Users/jacek/.ivy2/cache/io.spray/spray-util_2.11/bundles/spray-util_2.11-1.3.2.jar
[debug] /Users/jacek/.ivy2/cache/io.spray/spray-http_2.11/bundles/spray-http_2.11-1.3.2.jar
[debug] /Users/jacek/.ivy2/cache/org.parboiled/parboiled-scala_2.11/bundles/parboiled-scala_2.11-1.1.6.jar
[debug] /Users/jacek/.ivy2/cache/org.parboiled/parboiled-core/bundles/parboiled-core-1.1.6.jar
[debug] /Users/jacek/.ivy2/cache/io.spray/spray-routing_2.11/bundles/spray-routing_2.11-1.3.2.jar
[debug] /Users/jacek/.ivy2/cache/io.spray/spray-httpx_2.11/bundles/spray-httpx_2.11-1.3.2.jar
[debug] /Users/jacek/.ivy2/cache/org.scala-lang.modules/scala-xml_2.11/bundles/scala-xml_2.11-1.0.2.jar
[debug] /Users/jacek/.ivy2/cache/org.jvnet.mimepull/mimepull/jars/mimepull-1.9.4.jar
[debug] /Users/jacek/.ivy2/cache/com.chuusai/shapeless_2.11/jars/shapeless_2.11-1.2.4.jar
[debug] /Users/jacek/.ivy2/cache/io.spray/spray-json_2.11/bundles/spray-json_2.11-1.3.1.jar
[debug] /Users/jacek/.ivy2/cache/com.typesafe.akka/akka-actor_2.11/jars/akka-actor_2.11-2.3.6.jar
[debug] /Users/jacek/.ivy2/cache/com.typesafe/config/bundles/config-1.2.1.jar
[debug] Waiting for thread run-main-0 to terminate.
[debug] Thread run-main-0 exited.
[debug] Waiting for thread default-akka.actor.default-dispatcher-4 to terminate.
Custom task to dump CLASSPATH
If you need to see what the run task depends on, use inspect.
[fullclasspath]> inspect run
[info] Input task: Unit
[info] Description:
[info] Runs a main class, passing along arguments provided on the command line.
[info] Provided by:
[info] {file:/Users/jacek/sandbox/so/fullClasspath/}fullclasspath/compile:run
[info] Defined at:
[info] (sbt.Defaults) Defaults.scala:704
[info] Dependencies:
[info] compile:run::streams
[info] runtime:fullClasspath
[info] compile:run::runner
[info] compile:run::mainClass
[info] Delegates:
[info] compile:run
[info] *:run
[info] {.}/compile:run
[info] {.}/*:run
[info] */compile:run
[info] */*:run
[info] Related:
[info] test:run
In Dependencies there's the runtime:fullClasspath setting which means that run depends on its value.
According to SBT help, fullClasspath is...
[fullclasspath]> help fullClasspath
The exported classpath, consisting of build products and unmanaged and managed, internal and external dependencies.
You simply need to parse the value of the runtime:fullClasspath setting.
[fullclasspath]> show runtime:fullClasspath
[info] Updating {file:/Users/jacek/sandbox/so/fullClasspath/}fullclasspath...
[info] Resolving org.fusesource.jansi#jansi;1.4 ...
[info] Done updating.
[info] List(Attributed(/Users/jacek/sandbox/so/fullClasspath/target/scala-2.10/classes), Attributed(/Users/jacek/.sbt/boot/scala-2.10.3/lib/scala-library.jar))
[success] Total time: 0 s, completed Feb 13, 2014 1:27:38 AM
To have a more parsable output, use the following task that reads fullClasspath as defined for the runtime scope (Runtime in Scala/SBT code):
lazy val printClasspath = taskKey[Unit]("Dump classpath")
printClasspath := {
(fullClasspath in Runtime value) foreach {
e => println(e.data)
}
}
Unfortunatelly, the Runtime configuration is hardcoded and think an input task to accept a configuration would make it so much better.

Answer 3

or directly from the bash , dash , sh or whatever shell:
sbt 'inspect run' 'show runtime:fullClasspath'
and
sbt "inspect run" "show runtime:fullClasspath"
for Windows command line.

Answer 4

Add the line lazy val printClasspath ... in your build.sbt file.
Then at the command line run:
sbt printClasspath