SBT/Play2 multi-project setup does not include dependant projects in classpath in run/test

Question

I have following SBT/Play2 multi-project setup:

import sbt._
import Keys._
import PlayProject._

object ApplicationBuild extends Build {
  val appName         = "traveltime-api"
  val appVersion      = "1.0"

  val appDependencies = Seq(
    // Google geocoding library
    "com.google.code.geocoder-java" % "geocoder-java" % "0.9",
    // Emailer
    "org.apache.commons" % "commons-email" % "1.2",
    // CSV generator
    "net.sf.opencsv" % "opencsv" % "2.0",

    "org.scalatest" %% "scalatest" % "1.7.2" % "test",
    "org.scalacheck" %% "scalacheck" % "1.10.0" % "test",
    "org.mockito" % "mockito-core" % "1.9.0" % "test"
  )

  val lib = RootProject(file("../lib"))
  val chiShape = RootProject(file("../chi-shape"))

  lazy val main = PlayProject(
    appName, appVersion, appDependencies, mainLang = SCALA
  ).settings(
    // Add your own project settings here
    resolvers ++= Seq(
      "Sonatype Snapshots" at
        "http://oss.sonatype.org/content/repositories/snapshots",
      "Sonatype Releases" at
        "http://oss.sonatype.org/content/repositories/releases"
    ),
    // Scalatest compatibility
    testOptions in Test := Nil
  ).aggregate(lib, chiShape).dependsOn(lib, chiShape)
}

As you can see this project depends on two independant subprojects: lib and chiShape.

Now compile works fine - all sources are correctly compiled. However if I try run or test, neither task in runtime has classes from subprojects on classpath loaded and things go haywire with NoClassFound exceptions.

For example - my application has to load serialized data from file and it goes like this: test starts FakeApplication, it tries to load data and boom:

[info] CsvGeneratorsTest:
[info] #markerFilterCsv 
[info] - should fail on bad json *** FAILED ***
[info]   java.lang.ClassNotFoundException: com.library.Node
[info]   at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
[info]   at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
[info]   at java.security.AccessController.doPrivileged(Native Method)
[info]   at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
[info]   at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
[info]   at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
[info]   at java.lang.Class.forName0(Native Method)
[info]   at java.lang.Class.forName(Class.java:264)
[info]   at java.io.ObjectInputStream.resolveClass(ObjectInputStream.java:622)
[info]   at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1593)
[info]   ...

Strangely enough stage creates a directory structure with chi-shapes_2.9.1-1.0.jar and lib_2.9.1-1.0.jar in staged/.

How can I get my runtime/test configurations get subprojects into classpath?

Update:

I've added following code to Global#onStart:

  override def onStart(app: Application) {
    println(app)
    ClassLoader.getSystemClassLoader.asInstanceOf[URLClassLoader].getURLs.
      foreach(println)
    throw new RuntimeException("foo!")
  }

When I launch tests, the classpath is very very ill populated, to say at least :)

FakeApplication(.,sbt.classpath.ClasspathUtilities$$anon$1@182253a,List(),List(),Map(application.load-data -> test, mailer.smtp.test-mode -> true))
file:/home/arturas/Software/sdks/play-2.0.3/framework/sbt/sbt-launch.jar
[info] CsvGeneratorsTest:

When launching staged app, there's a lot of stuff, how it's supposed to be :)

$ target/start
Play server process ID is 29045
play.api.Application@1c2862b
file:/home/arturas/work/traveltime-api/api/target/staged/jul-to-slf4j.jar

That's strange, because there should be at least testing jars in the classpath I suppose?

Answer 1

It seems I've solved it.

The culprit was that ObjectInputStream ignores thread local class loaders by default and only uses system class loader.

So I changed from:

  def unserialize[T](file: File): T = {
    val in = new ObjectInputStream(new FileInputStream(file))
    try {
      in.readObject().asInstanceOf[T]
    }
    finally {
      in.close
    }
  }

To:

  /**
   * Object input stream which respects thread local class loader.
   *
   * TL class loader is used by SBT to avoid polluting system class loader when
   * running different tasks.
   */
  class TLObjectInputStream(in: InputStream) extends ObjectInputStream(in) {
    override protected def resolveClass(desc: ObjectStreamClass): Class[_] = {
      Option(Thread.currentThread().getContextClassLoader).map { cl =>
        try { return cl.loadClass(desc.getName)}
        catch { case (e: java.lang.ClassNotFoundException) => () }
      }
      super.resolveClass(desc)
    }
  }

  def unserialize[T](file: File): T = {
    val in = new TLObjectInputStream(new FileInputStream(file))
    try {
      in.readObject().asInstanceOf[T]
    }
    finally {
      in.close
    }
  }

And my class not found problems went away!

Thanks to How to put custom ClassLoader to use? and http://tech-tauk.blogspot.com/2010/05/thread-context-classlaoder-in.html on useful insight about deserializing and thread local class loaders.