SBT sub-project inter-dependencies

Where have I gone wrong with this SBT project configuration?

I have a parent project A, with subprojects B1 and B2, and B2 depends on project B1.

B1 compiles successfully; but B2's compilation fails because it cannot find B1's classes.

import sbt._

class A(info: ProjectInfo) extends ParentProject(info) with IdeaProject {
  lazy val B1 = project("b1", "B1", new B1(_))
  lazy val B2 = project("b2", "B2", new B2(_))

  class B1(info: ProjectInfo) extends DefaultWebProject(info) with IdeaProject {
    override def unmanagedClasspath = super.unmanagedClasspath +++ extraJars
    def baseDirectory = "lib"
    def extraJars = descendents(baseDirectory, "*.jar")
  }

  class B2(info: ProjectInfo) extends DefaultProject(info) with IdeaProject {
    override def deliv开发者_如何学PythonerProjectDependencies = 
      B1.projectID :: super.deliverProjectDependencies.toList
  }
}

I'm really not sure if I've defined the dependency between B2 and B1 correctly. I would have specified it using the project method with this signature:

def project(path: Path, name: String, deps: Project*): Project

... but I need the subprojects to mix in the IdeaProject trait.

---

Well, you're using the other signature, though:

def project [P <: Project](path : Path, name : java.lang.String, construct : (ProjectInfo) => P, deps : Project*) : P

So, you need B2 to declare a dependency on B1.

lazy val B2 = project("b2", "B2", new B2(_), B1)

Note: I'm pretty sure I'd rename the variables to not be the same as the class name here, because that just confuses me, and while it should work, that just seems funky.

---

Answering my own question in case someone else finds it useful. This folds in the solution provided by Tristan Juricek:

import sbt._

class ActiveMinutesProject(info: ProjectInfo) extends ParentProject(info) with IdeaProject {
  lazy val amweb = project("amweb", "ActiveMinutes web application", new AMWeb(_))
  lazy val amadmin = project("amadmin", "ActiveMinutes administration", new AMAdmin(_), amweb)

  class AMWeb(info: ProjectInfo) extends DefaultWebProject(info) with IdeaProject {
    override def unmanagedClasspath = super.unmanagedClasspath +++ extraJars
    def baseDirectory = "lib"
    def extraJars = descendents(baseDirectory, "*.jar")
  }

  class AMAdmin(info: ProjectInfo) extends DefaultProject(info) with IdeaProject {}
}