embeddedDefaults vs URLClasspath scanning

build.properties

sbt.version=0.13.8

build.sbt

scalaVersion := "2.11.7"

libraryDependencies += "org.scala-lang.modules" %% "scala-async" % "0.9.5"

libraryDependencies += "org.scala-lang" % "scala-compiler" % scalaVersion.value

run.log

% sbt "set fork in run := false" run
[info] Loading global plugins from /Users/jason/.sbt/0.13/plugins
[info] Loading project definition from /Users/jason/code/scratch1/project
[info] Set current project to scratch1 (in build file:/Users/jason/code/scratch1/)
[info] Defining *:run::fork
[info] The new value will be used by compile:run::runner, test:run::runner
[info] Reapplying settings...
[info] Set current project to scratch1 (in build file:/Users/jason/code/scratch1/)
[info] Running Test
u.getURLs = /Users/jason/code/scratch1/target/scala-2.11/classes:/Users/jason/.ivy2/cache/org.scala-lang/scala-compiler/jars/scala-compiler-2.11.7.jar:/Users/jason/.ivy2/cache/org.scala-lang/scala-library/jars/scala-library-2.11.7.jar:/Users/jason/.ivy2/cache/org.scala-lang/scala-reflect/jars/scala-reflect-2.11.7.jar:/Users/jason/.ivy2/cache/org.scala-lang.modules/scala-xml_2.11/bundles/scala-xml_2.11-1.0.4.jar:/Users/jason/.ivy2/cache/org.scala-lang.modules/scala-parser-combinators_2.11/bundles/scala-parser-combinators_2.11-1.0.4.jar:/Users/jason/.ivy2/cache/org.scala-lang.modules/scala-async_2.11/bundles/scala-async_2.11-0.9.5.jar
embeddedDefaults
 - classpath: /Users/jason/code/scratch1/target/scala-2.11/classes:/Users/jason/.ivy2/cache/org.scala-lang/scala-compiler/jars/scala-compiler-2.11.7.jar:/Users/jason/.ivy2/cache/org.scala-lang/scala-library/jars/scala-library-2.11.7.jar:/Users/jason/.ivy2/cache/org.scala-lang/scala-reflect/jars/scala-reflect-2.11.7.jar:/Users/jason/.ivy2/cache/org.scala-lang.modules/scala-xml_2.11/bundles/scala-xml_2.11-1.0.4.jar:/Users/jason/.ivy2/cache/org.scala-lang.modules/scala-parser-combinators_2.11/bundles/scala-parser-combinators_2.11-1.0.4.jar:/Users/jason/.ivy2/cache/org.scala-lang.modules/scala-async_2.11/bundles/scala-async_2.11-0.9.5.jar
 - bootclasspath: /Users/jason/.ivy2/cache/org.scala-lang/scala-library/jars/scala-library-2.11.7.jar:/Users/jason/.ivy2/cache/org.scala-lang/scala-compiler/jars/scala-compiler-2.11.7.jar:/Users/jason/.ivy2/cache/org.scala-lang/scala-reflect/jars/scala-reflect-2.11.7.jar:/Users/jason/.ivy2/cache/org.scala-lang.modules/scala-xml_2.11/bundles/scala-xml_2.11-1.0.4.jar:/Users/jason/.ivy2/cache/org.scala-lang.modules/scala-parser-combinators_2.11/bundles/scala-parser-combinators_2.11-1.0.4.jar:/Users/jason/.ivy2/cache/jline/jline/jars/jline-2.12.1.jar
[success] Total time: 1 s, completed 16/09/2015 11:30:16 AM

⚡ sbt "set fork in run := true" run
[info] Loading global plugins from /Users/jason/.sbt/0.13/plugins
[info] Loading project definition from /Users/jason/code/scratch1/project
[info] Set current project to scratch1 (in build file:/Users/jason/code/scratch1/)
[info] Defining *:run::fork
[info] The new value will be used by compile:run::runner, test:run::runner
[info] Reapplying settings...
[info] Set current project to scratch1 (in build file:/Users/jason/code/scratch1/)
[info] Running Test
[info] u.getURLs = /Users/jason/code/scratch1/target/scala-2.11/classes:/Users/jason/.ivy2/cache/org.scala-lang/scala-compiler/jars/scala-compiler-2.11.7.jar:/Users/jason/.ivy2/cache/org.scala-lang/scala-library/jars/scala-library-2.11.7.jar:/Users/jason/.ivy2/cache/org.scala-lang/scala-reflect/jars/scala-reflect-2.11.7.jar:/Users/jason/.ivy2/cache/org.scala-lang.modules/scala-xml_2.11/bundles/scala-xml_2.11-1.0.4.jar:/Users/jason/.ivy2/cache/org.scala-lang.modules/scala-parser-combinators_2.11/bundles/scala-parser-combinators_2.11-1.0.4.jar:/Users/jason/.ivy2/cache/org.scala-lang.modules/scala-async_2.11/bundles/scala-async_2.11-0.9.5.jar
[info] embeddedDefaults
[info]  - classpath: .
[info]  - bootclasspath:
[success] Total time: 0 s, completed 16/09/2015 11:30:29 AM

Test.scala

import java.net.URLClassLoader

object Test {
  def main(args: Array[String]): Unit = {
    val loader = getClass.getClassLoader
    loader match {
      case u: URLClassLoader => println("u.getURLs = " + u.getURLs.map(u => new java.io.File(u.toURI).toString).mkString(":"))
      case _ => println("loader.getClass", loader.getClass)
    }
    val settings = new scala.tools.nsc.Settings
    settings.embeddedDefaults[Test.type]
    println("embeddedDefaults")
    println(" - classpath: " + settings.classpath.value)
    println(" - bootclasspath: " + settings.bootclasspath.value)
  }
}