Merge pull request #412 from cvogt/chris

various

24 files changed, 379 insertions, 167 deletions

diff --git a/build/build.scala b/build/build.scala
index b4a39ea..4114bc5 100644
--- a/build/build.scala
+++ b/build/build.scala
@@ -1,6 +1,12 @@
 import cbt._
+import cbt_internal._
+
+class Build(val context: Context) extends Shared{
+  override def name: String = "cbt"
+  override def version: String = ???
+  override def description: String = "Fast, intuitive Build Tool for Scala"
+  override def inceptionYear: Int = 2015
 
-class Build(val context: Context) extends Publish{
   // FIXME: somehow consolidate this with cbt's own boot-strapping from source.
   override def dependencies = {
     super.dependencies ++ Resolver(mavenCentral).bind(
@@ -9,22 +15,8 @@ class Build(val context: Context) extends Publish{
       ScalaDependency("org.scala-lang.modules","scala-xml","1.0.5")
     )
   }
+
   override def sources = Seq(
     "nailgun_launcher", "stage1", "stage2", "compatibility"
-  ).map(d => projectDirectory ++ ("/" + d))
-
-  def groupId: String = "org.cvogt"
-
-  def version: String = "0.9"
-  override def name: String = "cbt"
-
-  // Members declared in cbt.Publish
-  def description: String = "Fast, intuitive Build Tool for Scala"
-  def developers: Seq[cbt.Developer] = Nil
-  def inceptionYear: Int = 2016
-  def licenses: Seq[cbt.License] = Seq( License.Apache2 )
-  def organization: Option[cbt.Organization] = None
-  def scmConnection: String = ""
-  def scmUrl: String = ""
-  def url: java.net.URL = new java.net.URL("http://github.com/cvogt/cbt/")
+  ).map( projectDirectory / _ ).flatMap( _.listFiles )
 }
diff --git a/build/build/build.scala b/build/build/build.scala
new file mode 100644
index 0000000..313b2b5
--- /dev/null
+++ b/build/build/build.scala
@@ -0,0 +1,7 @@
+package cbt_build.cbt.build
+import cbt._
+class Build(val context: Context) extends CbtInternal{
+  override def dependencies = (
+    super.dependencies :+ cbtInternal.shared
+  )
+}
diff --git a/circle.yml b/circle.yml
index 0a6f9d5..92b8983 100644
--- a/circle.yml
+++ b/circle.yml
@@ -13,7 +13,7 @@ dependencies:
 test:
   override:
     - rm ~/.gitconfig # avoid url replacement breaking jgit
-    - ./cbt direct test.run:
+    - ./cbt direct test.run slow:
         timeout: 1800
-    - ./cbt test.run:
+    - ./cbt test.run slow:
         timeout: 1800
diff --git a/doc/cbt-developer/version-compatibility.md b/doc/cbt-developer/version-compatibility.md
new file mode 100644
index 0000000..986bb37
--- /dev/null
+++ b/doc/cbt-developer/version-compatibility.md
@@ -0,0 +1,50 @@
+## Why does CBT version compatiblity matter?
+CBT allows fixing the version used using the `// cbt: ` annotation.
+This means that the CBT version you installed will download the
+CBT version referenced there and use that instead. CBT also
+allows composing builds, which require different CBT versions.
+In order for all of this to work, different CBT versions need to
+be able to talk to one another.
+
+This chapter is about how the current solution works and about
+the pitfalls involved which can make a new version of CBT
+incompatible with older versions.
+
+## How can compatibility be broken?
+The current solution mostly relies on the Java interfaces in
+the `compability/` folder. Changing the Java interface in a
+non-backwards-compatible way means making the CBT incompatible with
+older versions. Java 8 default methods make this a whole lot easier
+and this is the main reason CBT relies on Java 8. But we also
+want to keep this interfaces as small as possible in order to
+minimize the risk.
+
+However there are more things that can break compatibility when changed:
+- the format of the `// cbt: ` version string
+- the name and format of Build classes (or files) that CBT looks for
+- communication between versions via reflection in particular
+  - how the TrapSecurityManager of each CBT version talks to the
+    installed TrapSecurityManager via reflection
+
+## How to detect accidental breakages?
+
+CBT's tests have a few tests with `// cbt: ` annotations and some
+reference libraries as Git dependencies that use these annotations.
+Many incompatibilities will lead to these tests failing, either with
+a compilation error against the `compatiblity/` interfaces or with
+a runtime exception or unexpected behavior in case other things are
+broken.
+
+## How an we improve the situation in the long run?
+
+In the long run we should think about how to reduce the risk
+or sometimes even unavoidability of incompatibilities.
+The unavoidability mostly stems from limitations of what Java
+interfaces can express. However Java 8 interfaces mostly work
+fairly well. We should consider using them for the cases that
+currently use reflection instead of reflection.
+
+If Java 8 interfaces still turn out to be a problem in the long run,
+we could consider an interface that we control completely, e.g.
+an internal serialization formation, which CBT versions use to talk
+to each other.
diff --git a/doc/design.txt b/doc/design.md
index 28bbdaa..28bbdaa 100644
--- a/doc/design.txt
+++ b/doc/design.md
diff --git a/doc/plugin-author-guide.md b/doc/plugin-author-guide.md
new file mode 100644
index 0000000..db0eede
--- /dev/null
+++ b/doc/plugin-author-guide.md
@@ -0,0 +1,105 @@
+## How to write an idiomatic CBT plugin?
+
+Write a small library that could be fully used outside of CBT's
+build classes and handles all the use cases you need. For example
+
+```
+object MyLibrary{
+ def doSomething( ... ) = // do something here
+}
+```
+
+Publish it as a library and you might be done right here.
+
+If your library requires configuration information commonly found
+in your build, like the sourceFiles, groupId, scalaVersion or else,
+consider offering a mixin trait, that pre-configures your library
+for user convenience. (Consider publishing them separately if that
+allows people to use your library outside of CBT with fewer
+dependencies.) Here is an example of a library with an
+accompanying mixin trait configuring the library for CBT.
+
+```
+package my.library
+object MyLibrary{
+  case class DoSomething( scalaVersion: String, ... ){
+    case class config( targetFile: File, affectBehavior: Boolean = true, ... ){
+      def apply = // really do something here
+    }
+  }
+}
+
+package my.plugin
+trait MyLibrary extends BaseBuild{
+  def doSomething = MyLibrary.DoSomething(scalaVersion, ...).config( scalaTarget / "my.file" )
+}
+```
+
+* Note: Do not override any common method like `compile` or `test` in a public plugin. *
+* Instead document recommendations where users should hook in your custom methods. *
+* This will help users understand their own builds. *
+
+See how we only define a single `def doSomething` in the MyLibrary
+trait? We did not define things like `def doSomethingTargetFile`.
+Instead we have a case class defined in the library which a user
+can .copy as needed to customize configuration. A user build could
+look like this:
+
+```
+class Build(val context: Context) extends MyLibrary{
+  override def doSomething = super.doSomething.copy(
+    affectBehavior = false
+  )
+}
+```
+
+As you can see a user can use .copy to override default behavior
+of your library.
+
+This nesting allows us to keep the global namespace small, which
+helps us lower the risk of global name clashes between different
+libraries. It also makes it clearer that `affectBehavior` is
+something specific to `MyLibary` which should help making builds
+easier to understand. Further this nesting means we don't need to
+encode namespaces in the names themselves, but use Scala's language
+features for that, which allows us to keep names nice and concise.
+
+You might wonder why there is a case class `DoSomething` rather
+than `scalaVersion` just being another parameter in case class
+`config`. Nesting case classes like this is a pattern that given
+the way we use them allows us to make it slightly harder to
+modify some parameters (the ones on the outer case class) than
+others (the ones on the inner case class). Why? Some are likely
+to need user customization, others are likely to break stuff if
+they are touched. Example: The scalaVersion is probably something
+you want to configure once consistently across your entire build.
+Otherwise you might end up accidentally packaging scala-2.11
+compiled class files as a jar with a `_2.10` artifact id.
+Changing which targetFile `doSomething` writes to however is
+something you should be able to safely change. Since we defined
+`doSomething` as
+`def doSomething = MyLibrary.DoSomething(...).config( ... )`
+overriding behavior in user code with .copy only affects
+the inner case class because super.doSomething is an instance
+of that:
+```
+  override def doSomething = super.doSomething.copy(
+    affectBehavior = false
+  )
+```
+Overriding things in class `DoSomething` is possible by creating
+an entire new instance of the outer one, but slightly harder
+preventing users from accidentally doing the wrong thing.
+
+Obviously this decisions what's dangerous to override and what
+is not can be a judgment call and not 100% clear.
+
+A few more conventions for more uniform plugin designs:
+If you only have one outer case class in yur plugin `object`,
+call the case class `apply` instead of `DoSomething`. If you
+need multiple (because you basically have several commands,
+each with their own private configuration), give it a name
+representing the operation, e.g. `compile` or `doc`. If there
+is only one inner case class inside of anothe case class,
+call it `config`, give it a name representing the operation,
+e.g. `compile` or `doc`.
diff --git a/examples/multi-combined-example/build/build/build.scala b/examples/multi-combined-example/build/build/build.scala
index b87351d..a5b0201 100644
--- a/examples/multi-combined-example/build/build/build.scala
+++ b/examples/multi-combined-example/build/build/build.scala
@@ -1,8 +1,8 @@
 package cbt_build.cbt_examples.multi_combined_example.build
 import cbt._
 class Build(val context: Context) extends BuildBuild{
-  //println(DirectoryDependency( projectDirectory / ".." / "sub4" / "build" ).dependency.exportedClasspath)
+  //println(DirectoryDependency( projectDirectory / ".." / "sub4" / "build" ).exportedClasspath)
   override def dependencies: Seq[cbt.Dependency] =
-    super.dependencies :+ DirectoryDependency( projectDirectory / ".." / "sub4" / "build" ).dependency
+    super.dependencies :+ DirectoryDependency( projectDirectory / ".." / "sub4" / "build" )
   def foo = DirectoryDependency( projectDirectory / ".." / "sub4" / "build" )
 }
diff --git a/internal/plugins/shared/Shared.scala b/internal/plugins/shared/Shared.scala
new file mode 100644
index 0000000..90bc4b2
--- /dev/null
+++ b/internal/plugins/shared/Shared.scala
@@ -0,0 +1,13 @@
+package cbt_internal
+import cbt._
+import java.net.URL
+trait Shared extends SonatypeRelease with SnapshotVersion with GithubPom{
+  override def user = "cvogt"
+  override def groupId = "org.cvogt"
+  override def organization = Some( Organization( "Jan Christopher Vogt", Some( new URL("http://cvogt.org") ) ) )
+  override def licenses = Seq( License.Apache2 )
+  override def developers = Seq(cvogt)
+  override def githubProject = "cbt"
+
+  def cvogt = Developer("cvogt", "Jan Christopher Vogt", "-5", new URL("https://github.com/cvogt/"))
+}
diff --git a/internal/plugins/shared/build/build.scala b/internal/plugins/shared/build/build.scala
new file mode 100644
index 0000000..1d6fc29
--- /dev/null
+++ b/internal/plugins/shared/build/build.scala
@@ -0,0 +1,5 @@
+package cbt_build.cbt_internal.library_build_plugin
+import cbt._
+class Build(val context: Context) extends Plugin{
+  override def dependencies = super.dependencies :+ plugins.sonatypeRelease
+}
diff --git a/libraries/proguard/build/build.scala b/libraries/proguard/build/build.scala
index c781ce2..3ca38b5 100644
--- a/libraries/proguard/build/build.scala
+++ b/libraries/proguard/build/build.scala
@@ -15,7 +15,7 @@ class Build(val context: Context) extends Scalafmt{
   }
 
   override def scalafmt = super.scalafmt.copy(
-    config = super.scalafmt.lib.cbtRecommendedConfig,
+    config = Scalafmt.cbtRecommendedConfig,
     whiteSpaceInParenthesis = true
   )
 
diff --git a/plugins/google-java-format/GoogleJavaFormat.scala b/plugins/google-java-format/GoogleJavaFormat.scala
new file mode 100644
index 0000000..cbccb94
--- /dev/null
+++ b/plugins/google-java-format/GoogleJavaFormat.scala
@@ -0,0 +1,34 @@
+package cbt
+
+import java.io.File
+import java.nio.file.Files._
+import java.nio.file._
+
+import com.google.googlejavaformat.java._
+
+trait GoogleJavaFormat extends BaseBuild {
+  def googleJavaFormat() = GoogleJavaFormat.apply( lib, sourceFiles.filter(_.string endsWith ".java") ).format
+}
+
+object GoogleJavaFormat{
+  case class apply( lib: Lib, files: Seq[File] ){
+    /** @param whiteSpaceInParenthesis more of a hack to make up for missing support in Scalafmt. Does not respect alignment and maxColumn. */
+    def format = {
+      val (successes, errors) = lib.transformFilesOrError( files, in =>
+        try{
+          Right( new Formatter().formatSource(in) )
+        } catch {
+          case e: FormatterException => Left( e )
+        }
+      )
+      if(errors.nonEmpty)
+        throw new RuntimeException(
+          "Google Java Format failed to parse some files:\n" ++ errors.map{
+            case (file, error) => file.string ++ ":" ++ error.toString
+          }.mkString("\n"),
+          errors.head._2
+        )
+      successes
+    }
+  }
+}
diff --git a/plugins/google-java-format/Immutable.java b/plugins/google-java-format/Immutable.java
new file mode 100644
index 0000000..5b3ff44
--- /dev/null
+++ b/plugins/google-java-format/Immutable.java
@@ -0,0 +1,5 @@
+package com.google.errorprone.annotations;
+// to suppress warning
+// "Class com.google.errorprone.annotations.Immutable not found - continuing with a stub."
+// there probably is a better solution
+public class Immutable{}
diff --git a/plugins/google-java-format/build/build.scala b/plugins/google-java-format/build/build.scala
new file mode 100644
index 0000000..50bc423
--- /dev/null
+++ b/plugins/google-java-format/build/build.scala
@@ -0,0 +1,9 @@
+import cbt._
+
+class Build(val context: Context) extends Plugin {
+  override def dependencies =
+    super.dependencies ++
+    Resolver( mavenCentral ).bind(
+      MavenDependency( "com.google.googlejavaformat", "google-java-format", "1.3" )
+    )
+}
diff --git a/plugins/scalafmt/Scalafmt.scala b/plugins/scalafmt/Scalafmt.scala
index 9d42cbd..5535964 100644
--- a/plugins/scalafmt/Scalafmt.scala
+++ b/plugins/scalafmt/Scalafmt.scala
@@ -12,16 +12,15 @@ import java.nio.file._
 trait Scalafmt extends BaseBuild {
   /** Reformat scala source code according to `scalafmtConfig` rules */
   def scalafmt = {
-    val scalafmtLib = new ScalafmtLib(lib)
-    scalafmtLib.format( sourceFiles ).config(
-      scalafmtLib.loadConfig(
+    Scalafmt.apply( lib, sourceFiles.filter(_.string endsWith ".scala") ).config(
+      Scalafmt.loadConfig(
         projectDirectory.toPath
       ) getOrElse ScalafmtConfig.default
     )
   }
 }
 
-class ScalafmtLib(lib: Lib){ scalafmtLib =>
+object Scalafmt{
   def userHome = Option( System.getProperty("user.home") ).map(Paths.get(_))
 
   /** Tries to load config from .scalafmt.conf in given directory or fallback directory */
@@ -34,22 +33,18 @@ class ScalafmtLib(lib: Lib){ scalafmtLib =>
       .flatMap ( file => StyleCache.getStyleForFile(file.toString) )
   }
 
-  case class format(files: Seq[File]){
-    /**
-      * @param whiteSpaceInParenthesis more of a hack to make up for missing support in Scalafmt. Does not respect alignment and maxColumn.
-      */
+  case class apply( lib: Lib, files: Seq[File] ){
+    /** @param whiteSpaceInParenthesis more of a hack to make up for missing support in Scalafmt. Does not respect alignment and maxColumn. */
     case class config(
-      config: ScalafmtConfig,
-      whiteSpaceInParenthesis: Boolean = false
+      config: ScalafmtConfig, whiteSpaceInParenthesis: Boolean = false
     ) extends (() => Seq[File]){
-      def lib = scalafmtLib
       def apply = {
-        val (successes, errors) = scalafmtLib.lib.transformFilesOrError(
+        val (successes, errors) = lib.transformFilesOrError(
           files,
           org.scalafmt.Scalafmt.format(_, config) match {
             case Formatted.Success(formatted) => Right(
               if( whiteSpaceInParenthesis ){
-                scalafmtLib.whiteSpaceInParenthesis(formatted)
+                Scalafmt.whiteSpaceInParenthesis(formatted)
               } else formatted
             )
             case Formatted.Failure( e ) => Left( e )
diff --git a/stage2/BasicBuild.scala b/stage2/BasicBuild.scala
index 0d8017f..68bda15 100644
--- a/stage2/BasicBuild.scala
+++ b/stage2/BasicBuild.scala
@@ -212,7 +212,7 @@ trait BaseBuild extends BuildInterface with DependencyImplementation with Trigge
     val testDirectory = projectDirectory / "test"
     if( (testDirectory / lib.buildDirectoryName / lib.buildFileName).exists ){
       // FIYME: maybe we can make loadRoot(...).finalBuild an Option some
-      DirectoryDependency( testDirectory ).dependency
+      DirectoryDependency( testDirectory )
     } else {
       new BasicBuild( context.copy(workingDirectory = testDirectory) ){
         override def dependencies = Seq(
diff --git a/stage2/BuildBuild.scala b/stage2/BuildBuild.scala
index c312df9..9d3458d 100644
--- a/stage2/BuildBuild.scala
+++ b/stage2/BuildBuild.scala
@@ -14,8 +14,9 @@ class plugins(implicit context: Context){
     context.copy(
       workingDirectory = context.cbtHome / "plugins" / dir
     )
-  ).dependency
+  )
   final lazy val essentials = plugin( "essentials" )
+  final lazy val googleJavaFormat = plugin( "google-java-format" )
   final lazy val proguard = plugin( "proguard" )
   final lazy val sbtLayout = plugin( "sbt_layout" )
   final lazy val scalafmt = plugin( "scalafmt" )
@@ -31,7 +32,7 @@ trait BuildBuildWithoutEssentials extends BaseBuild{
 
   assert(
     projectDirectory.getName === lib.buildDirectoryName,
-    "You can't extend ${lib.buildBuildClassName} in: " + projectDirectory + "/" + lib.buildDirectoryName
+    s"You can't extend ${lib.buildBuildClassName} in: " + projectDirectory + "/" + lib.buildDirectoryName
   )
 
   protected final val managedContext = context.copy(
@@ -66,9 +67,9 @@ trait BuildBuildWithoutEssentials extends BaseBuild{
               // otherwise we'd have to recursively build all versions since
               // the beginning. Instead CBT always needs to build the pure Java
               // Launcher in the checkout with itself and then run it via reflection.
-              val dep = new GitDependency(base, hash, Some("nailgun_launcher"))
-              val ctx = managedContext.copy( cbtHome = dep.checkout )
-              dep.classLoader
+              val build = GitDependency(base, hash, Some("nailgun_launcher")).asInstanceOf[BaseBuild]
+              val ctx = managedContext.copy( cbtHome = build.projectDirectory.getParentFile )
+              build.classLoader
                 .loadClass( "cbt.NailgunLauncher" )
                 .getMethod( "getBuild", classOf[AnyRef] )
                 .invoke( null, ctx )
@@ -116,3 +117,10 @@ trait BuildBuildWithoutEssentials extends BaseBuild{
     if( c == p ) this else managedBuild.finalBuild( current )
   }
 }
+
+trait CbtInternal extends BuildBuild{
+  protected object cbtInternal{
+    def shared = DirectoryDependency(context.cbtHome / "/internal/plugins/shared")
+    def library = DirectoryDependency(context.cbtHome / "/internal/plugins/library")
+  }
+}
diff --git a/stage2/BuildDependency.scala b/stage2/BuildDependency.scala
index 9a2918a..d7520d8 100644
--- a/stage2/BuildDependency.scala
+++ b/stage2/BuildDependency.scala
@@ -15,43 +15,39 @@ trait TriggerLoop extends DependencyImplementation{
   def triggerLoopFiles: Seq[File]
 }
 /** You likely want to use the factory method in the BasicBuild class instead of this. */
-final case class DirectoryDependency(context: Context, pathToNestedBuild: String*) extends TriggerLoop{
-  def classLoaderCache = context.classLoaderCache
-  override def toString = show
-  override def show = this.getClass.getSimpleName ++ "(" ++ context.workingDirectory.string ++ ")"
-  def moduleKey = this.getClass.getName ++ "("+context.workingDirectory.string+")"
-  lazy val logger = context.logger
-  override lazy val lib: Lib = new Lib(logger)
-  def transientCache = context.transientCache
-  private lazy val root = lib.loadRoot( context )
-  lazy val dependency: Dependency = {
+object DirectoryDependency{
+  def apply(context: Context, pathToNestedBuild: String*): BuildInterface = {
+    val lib: Lib = new Lib(context.logger)
+
     // TODO: move this into finalBuild probably
-    def selectNestedBuild( build: Dependency, names: Seq[String], previous: Seq[String] ): Dependency = {
+    // TODO: unify this with lib.callReflective
+    def selectNestedBuild( build: BuildInterface, names: Seq[String], previous: Seq[String] ): BuildInterface = {
       names.headOption.map{ name =>
         if( lib.taskNames(build.getClass).contains(name) ){
           val method = build.getClass.getMethod(name)
           val returnType = method.getReturnType
-          if( classOf[Dependency] isAssignableFrom returnType ){
+          if( classOf[BuildInterface] isAssignableFrom returnType ){
             selectNestedBuild(
-              method.invoke(build).asInstanceOf[Dependency],
+              method.invoke(build).asInstanceOf[BuildInterface],
               names.tail,
               previous :+ name
             )
           } else {
-            throw new RuntimeException( s"Expected subtype of Dependency, found $returnType for  " + previous.mkString(".") + " in " + show )
+            throw new RuntimeException(
+              s"Expected subtype of BuildInterface, found $returnType for  " + previous.mkString(".") + " in " + build
+            )
           }
         } else {
-          throw new RuntimeException( (previous :+ name).mkString(".") + " not found in " + show )
+          throw new RuntimeException( (previous :+ name).mkString(".") + " not found in " + build )
         }
       }.getOrElse( build )
     }
-    selectNestedBuild( root.finalBuild(context.workingDirectory), pathToNestedBuild, Nil )
+    selectNestedBuild(
+      lib.loadRoot( context ).finalBuild(context.workingDirectory),
+      pathToNestedBuild,
+      Nil
+    )
   }
-  def exportedClasspath = ClassPath()
-  def dependencies = Seq(dependency)
-  def triggerLoopFiles = root.triggerLoopFiles
-  def lastModified = dependency.lastModified
-  def targetClasspath = ClassPath()
 }
 /*
 case class DependencyOr(first: DirectoryDependency, second: JavaDependency) extends ProjectProxy with DirectoryDependencyBase{
@@ -59,4 +55,4 @@ case class DependencyOr(first: DirectoryDependency, second: JavaDependency) exte
   def triggerLoopFiles = if(isFirst) first.triggerLoopFiles else Seq()
   protected val delegate = if(isFirst) first else second
 }
-*/
\ No newline at end of file
+*/
diff --git a/stage2/GitDependency.scala b/stage2/GitDependency.scala
index f2ac7a6..028401b 100644
--- a/stage2/GitDependency.scala
+++ b/stage2/GitDependency.scala
@@ -9,70 +9,68 @@ import org.eclipse.jgit.lib.Ref
 
 object GitDependency{
   val GitUrl = "(git:|https:|file:/)//([^/]+)/(.+)".r
-}
-case class GitDependency(
-  url: String, ref: String, subDirectory: Option[String] = None, // example: git://github.com/cvogt/cbt.git#<some-hash>
-  pathToNestedBuild: Seq[String] = Seq()
-)(implicit val logger: Logger, classLoaderCache: ClassLoaderCache, context: Context ) extends DependencyImplementation{
-  import GitDependency._
-  override def lib = new Lib(logger)
-  def classLoaderCache = context.classLoaderCache
-  def moduleKey = (
-    this.getClass.getName
-    ++ "(" ++ url ++ subDirectory.map("/" ++ _).getOrElse("") ++ "#" ++ ref
-    ++ ", "
-    ++ pathToNestedBuild.mkString(", ")
-    ++ ")"
-  )
-  def transientCache = context.transientCache
-  // TODO: add support for authentication via ssh and/or https
-  // See http://www.codeaffine.com/2014/12/09/jgit-authentication/
-  private val GitUrl( _, domain, path ) = url  
+  def apply(
+    url: String, ref: String, subDirectory: Option[String] = None, // example: git://github.com/cvogt/cbt.git#<some-hash>
+    pathToNestedBuild: Seq[String] = Seq()
+  )(implicit context: Context ): BuildInterface = {
+    // TODO: add support for authentication via ssh and/or https
+    // See http://www.codeaffine.com/2014/12/09/jgit-authentication/
+    val GitUrl( _, domain, path ) = url
+    val credentialsFile = context.workingDirectory ++ "/git.login"
+    def authenticate(_git: CloneCommand) =
+      if(!credentialsFile.exists){
+        _git
+      } else {
+        val (user, password) = {
+          // TODO: implement safer method than reading credentials from plain text file
+          val c = new String(readAllBytes(credentialsFile.toPath)).split("\n").head.trim.split(":")
+          (c(0), c.drop(1).mkString(":"))
+        }
+        _git.setCredentialsProvider( new UsernamePasswordCredentialsProvider(user, password) )
+      }
 
-  private val credentialsFile = context.workingDirectory ++ "/git.login"
+    val logger = context.logger
 
-  private def authenticate(_git: CloneCommand) =
-    if(!credentialsFile.exists){
-      _git
-    } else {
-      val (user, password) = {
-        // TODO: implement safer method than reading credentials from plain text file
-        val c = new String(readAllBytes(credentialsFile.toPath)).split("\n").head.trim.split(":")
-        (c(0), c.drop(1).mkString(":"))
-      }
-      _git.setCredentialsProvider( new UsernamePasswordCredentialsProvider(user, password) )
-    }
+    def moduleKey = (
+      this.getClass.getName
+      ++ "(" ++ url ++ subDirectory.map("/" ++ _).getOrElse("") ++ "#" ++ ref
+      ++ ", "
+      ++ pathToNestedBuild.mkString(", ")
+      ++ ")"
+    )
 
-  def checkout: File = taskCache[GitDependency]("checkout").memoize{
-    val checkoutDirectory = context.cache ++ s"/git/$domain/$path/$ref"
-    val _git = if(checkoutDirectory.exists){
-      logger.git(s"Found existing checkout of $url#$ref in $checkoutDirectory")
-      val _git = new Git(new FileRepository(checkoutDirectory ++ "/.git"))
-      val actualRef = _git.getRepository.getBranch
-      if(actualRef != ref){
-        logger.git(s"actual ref '$actualRef' does not match expected ref '$ref' - fetching and checking out")
-        _git.fetch().call()
-        _git.checkout().setName(ref).call
-      }
-      _git
-    } else {
-      logger.git(s"Cloning $url into $checkoutDirectory")
-      val _git = authenticate(
-        Git
-          .cloneRepository()
-          .setURI(url)
-          .setDirectory(checkoutDirectory)
-      ).call()
+    val taskCache = new PerClassCache(context.transientCache, moduleKey)(logger)
 
-      logger.git(s"Checking out ref $ref")
-      _git.checkout().setName(ref).call()
-      _git
+    def checkout: File = taskCache[Dependency]("checkout").memoize{
+      val checkoutDirectory = context.cache ++ s"/git/$domain/$path/$ref"
+      val _git = if(checkoutDirectory.exists){
+        logger.git(s"Found existing checkout of $url#$ref in $checkoutDirectory")
+        val _git = new Git(new FileRepository(checkoutDirectory ++ "/.git"))
+        val actualRef = _git.getRepository.getBranch
+        if(actualRef != ref){
+          logger.git(s"actual ref '$actualRef' does not match expected ref '$ref' - fetching and checking out")
+          _git.fetch().call()
+          _git.checkout().setName(ref).call
+        }
+        _git
+      } else {
+        logger.git(s"Cloning $url into $checkoutDirectory")
+        val _git = authenticate(
+          Git
+            .cloneRepository()
+            .setURI(url)
+            .setDirectory(checkoutDirectory)
+        ).call()
+
+        logger.git(s"Checking out ref $ref")
+        _git.checkout().setName(ref).call()
+        _git
+      }
+      val actualRef = _git.getRepository.getBranch
+      assert( actualRef == ref, s"actual ref '$actualRef' does not match expected ref '$ref'")
+      checkoutDirectory
     }
-    val actualRef = _git.getRepository.getBranch
-    assert( actualRef == ref, s"actual ref '$actualRef' does not match expected ref '$ref'")
-    checkoutDirectory
-  }
-  def dependency = taskCache[GitDependency]("dependency").memoize{
+
     DirectoryDependency(
       context.copy(
         workingDirectory = checkout ++ subDirectory.map("/" ++ _).getOrElse("")
@@ -80,10 +78,4 @@ case class GitDependency(
       pathToNestedBuild: _*
     )
   }
-
-  def dependencies = Seq(dependency)
-
-  def exportedClasspath = ClassPath()
-  private[cbt] def targetClasspath = exportedClasspath
-  def lastModified: Long = dependency.lastModified
 }
diff --git a/stage2/Scaffold.scala b/stage2/Scaffold.scala
index 4420866..30ea73b 100644
--- a/stage2/Scaffold.scala
+++ b/stage2/Scaffold.scala
@@ -43,6 +43,11 @@ class Scaffold( logger: Logger ){
     )
   }
 
+  private[cbt] def buildPackageFromDirectory(directory: File) = {
+    val parts = packageFromDirectory(directory).split("\\.")
+    ((parts.head ++ "_build") +: parts.tail).mkString(".")
+  }
+
   def createMain(
     projectDirectory: File
   ): Unit = {
@@ -59,7 +64,7 @@ object Main{
   def createBuild(
     projectDirectory: File
   ): Unit = {
-    createFile(projectDirectory, lib.buildDirectoryName++"/"++lib.buildFileName, s"""package cbt_build.${packageFromDirectory(projectDirectory)}
+    createFile(projectDirectory, lib.buildDirectoryName++"/"++lib.buildFileName, s"""package ${buildPackageFromDirectory(projectDirectory)}
 import cbt._
 class Build(val context: Context) extends BaseBuild{
   override def dependencies = (
diff --git a/test/simple-fixed/Main.scala b/test/simple-fixed/Main.scala
index 75f9349..54c764c 100644
--- a/test/simple-fixed/Main.scala
+++ b/test/simple-fixed/Main.scala
@@ -1,6 +1,4 @@
 import lib_test.Foo
-import org.eclipse.jgit.lib.Ref
-import com.spotify.missinglink.ArtifactLoader
 object Main extends App{
   println(Foo.bar)
 }
diff --git a/test/simple-fixed/build/build.scala b/test/simple-fixed/build/build.scala
index b46c337..0215c43 100644
--- a/test/simple-fixed/build/build.scala
+++ b/test/simple-fixed/build/build.scala
@@ -7,23 +7,5 @@ class Build(context: cbt.Context) extends BasicBuild(context){
     Seq(
       GitDependency("https://github.com/cvogt/cbt.git", "f11b8318b85f16843d8cfa0743f64c1576614ad6", Some("test/library-test"))
     )
-    ++
-    Resolver(mavenCentral).bind(
-      ScalaDependency("com.typesafe.play", "play-json", "2.4.4"),
-      MavenDependency("joda-time", "joda-time", "2.9.2"),
-      // the below tests pom inheritance with dependencyManagement and variable substitution for pom properties
-      MavenDependency("org.eclipse.jgit", "org.eclipse.jgit", "4.2.0.201601211800-r"),
-      // the below tests pom inheritance with variable substitution for pom xml tag contents
-      MavenDependency("com.spotify", "missinglink-core", "0.1.1")
-    )
-    ++
-    Resolver(
-      mavenCentral,
-      bintray("tpolecat"),
-      sonatypeSnapshots
-    ).bind(
-      "org.cvogt" %% "play-json-extensions" % "0.8.0",
-      "ai.x" %% "lens" % "1.0.0"
-    )
   )
 }
diff --git a/test/simple/Main.scala b/test/simple/Main.scala
index 75f9349..c742110 100644
--- a/test/simple/Main.scala
+++ b/test/simple/Main.scala
@@ -1,6 +1,5 @@
-import lib_test.Foo
 import org.eclipse.jgit.lib.Ref
 import com.spotify.missinglink.ArtifactLoader
 object Main extends App{
-  println(Foo.bar)
+  println("hello, world")
 }
diff --git a/test/simple/build/build.scala b/test/simple/build/build.scala
index a132dd1..517dd83 100644
--- a/test/simple/build/build.scala
+++ b/test/simple/build/build.scala
@@ -4,9 +4,6 @@ class Build(val context: cbt.Context) extends BaseBuild{
   override def dependencies = (
     super.dependencies
     ++
-    Seq(
-      GitDependency("https://github.com/cvogt/cbt.git", "f11b8318b85f16843d8cfa0743f64c1576614ad6", Some("test/library-test"))
-    ) ++
     // FIXME: make the below less verbose
     Resolver( mavenCentral ).bind(
       ScalaDependency("com.typesafe.play", "play-json", "2.4.4"),
@@ -38,6 +35,6 @@ class Build(val context: cbt.Context) extends BaseBuild{
       "ai.x" %% "lens" % "1.0.0"
     )
   )
-  
+
   def printArgs = context.args.mkString(" ")
 }
diff --git a/test/test.scala b/test/test.scala
index 59a85ac..45315ce 100644
--- a/test/test.scala
+++ b/test/test.scala
@@ -15,10 +15,20 @@ object Main{
     val lib = new Lib(logger)
     val cbtHome = new File(System.getenv("CBT_HOME"))
     
+
+    val slow = (
+      System.getenv("CIRCLECI") != null // enable only on circle
+      || args.args.contains("slow")
+    )
+    val compat = !args.args.contains("no-compat")
+
+    if(!slow) System.err.println( "Skipping slow tests" )
+    if(!compat) System.err.println( "Skipping cbt version compatibility tests" )
+
     var successes = 0
     var failures = 0
     def assertException[T:scala.reflect.ClassTag](msg: String = "")(code: => Unit)(implicit logger: Logger) = {
-      try{ 
+      try{
         code
         assert(false, msg)
       }catch{ case _:AssertionError => }
@@ -187,9 +197,11 @@ object Main{
     usage("simple")
     compile("simple")
     clean("simple")
-    usage("simple-fixed")
-    compile("simple-fixed")
-    
+    if( compat ){
+      usage("simple-fixed")
+      compile("simple-fixed")
+    }
+
     compile("../plugins/sbt_layout")
     compile("../plugins/scalafmt")
     compile("../plugins/scalajs")
@@ -200,8 +212,12 @@ object Main{
     compile("../examples/scalafmt-example")
     compile("../examples/scalariform-example")
     compile("../examples/scalatest-example")
-    compile("../examples/scalajs-react-example/js")
-    compile("../examples/scalajs-react-example/jvm")
+    if(slow){
+      compile("../examples/scalajs-react-example/js")
+      compile("../examples/scalajs-react-example/jvm")
+      compile("../examples/scalajs-plain-example/js")
+      compile("../examples/scalajs-plain-example/jvm")
+    }
     compile("../examples/multi-standalone-example")
     compile("../examples/multi-combined-example")
     if(sys.props("java.version").startsWith("1.7")){
@@ -209,19 +225,23 @@ object Main{
     } else {
       compile("../examples/dotty-example")
       task("run","../examples/dotty-example")
-      task("dottydoc","../examples/dotty-example")
+      if(slow){
+        task("dottydoc","../examples/dotty-example")
+      }
+    }
+    if(slow){
+      task("compile","../examples/scalajs-react-example/js")
+      task("fullOpt.compile","../examples/scalajs-react-example/js")
     }
-    task("compile","../examples/scalajs-react-example/js")
-    task("fullOpt.compile","../examples/scalajs-react-example/js")
     compile("../examples/uber-jar-example")
-    
-    {
+
+    if( compat ){
       val res = task("docJar","simple-fixed-cbt")
       assert( res.out endsWith "simple-fixed-cbt_2.11-0.1-javadoc.jar\n", res.out )
       assert( res.err contains "model contains", res.err )
       assert( res.err endsWith "documentable templates\n", res.err )
     }
-    
+
     {
       val res = runCbt("simple", Seq("printArgs","1","2","3"))
       assert(res.exit0)