- Swap `Task.traverse` implementation to match behavior of other `traverse` implementations, added a `Task.sequence` that does what `traverse` used to do

- Added a `test.sh` script to easily kick off self-hosted unit test runs

- Tweak `ScalaModule` to fall back to the old behavior of including the transitive classpath during compilation

4 files changed, 39 insertions, 21 deletions

diff --git a/build.sc b/build.sc
index fb1b2d2d..24509943 100755
--- a/build.sc
+++ b/build.sc
@@ -106,7 +106,7 @@ object ScalaPlugin extends MillModule {
   def projectDeps = Seq(Core)
   def basePath = pwd / 'scalaplugin
 
-  def bridgeCompiles = mill.define.Task.traverse(bridges.items.map(_._2.compile))
+  def bridgeCompiles = mill.define.Task.traverse(bridges.items)(_._2.compile)
   def testArgs = T{
     val bridgeVersions = bridges.items.map(_._1.head.toString)
 
@@ -122,7 +122,7 @@ object ScalaPlugin extends MillModule {
 
 val assemblyProjects = Seq(ScalaPlugin)
 
-def assemblyClasspath = mill.define.Task.traverse(assemblyProjects.map(_.assemblyClasspath))
+def assemblyClasspath = mill.define.Task.traverse(assemblyProjects)(_.assemblyClasspath)
 
 def assemblyBase(classpath: Seq[Path], extraArgs: String)
                 (implicit ctx: mill.util.Ctx.DestCtx) = {
diff --git a/core/src/main/scala/mill/define/Task.scala b/core/src/main/scala/mill/define/Task.scala
index 8393acfb..d8ca8499 100644
--- a/core/src/main/scala/mill/define/Task.scala
+++ b/core/src/main/scala/mill/define/Task.scala
@@ -182,10 +182,12 @@ object Task {
 
   }
 
-  def traverse[T](source: Seq[Task[T]]) = {
-    new Traverse[T](source)
+  def traverse[T, V](source: Seq[T])(f: T => Task[V]) = {
+    new Sequence[V](source.map(f))
   }
-  class Traverse[+T](inputs0: Seq[Task[T]]) extends Task[Seq[T]]{
+  def sequence[T](source: Seq[Task[T]]) = new Sequence[T](source)
+
+  class Sequence[+T](inputs0: Seq[Task[T]]) extends Task[Seq[T]]{
     val inputs = inputs0
     def evaluate(args: Ctx) = {
       for (i <- 0 until args.length)
diff --git a/scalaplugin/src/main/scala/mill/scalaplugin/ScalaModule.scala b/scalaplugin/src/main/scala/mill/scalaplugin/ScalaModule.scala
index 1ba15061..9f9425a4 100644
--- a/scalaplugin/src/main/scala/mill/scalaplugin/ScalaModule.scala
+++ b/scalaplugin/src/main/scala/mill/scalaplugin/ScalaModule.scala
@@ -78,21 +78,18 @@ trait ScalaModule extends Module with TaskModule{ outer =>
 
 
   def upstreamRunClasspath = T{
-    Task.traverse(
-      for (p <- projectDeps)
-      yield T.task(p.runDepClasspath() ++ Seq(p.compile().classes, p.resources()))
+    Task.traverse(projectDeps)(p =>
+      T.task(p.runDepClasspath() ++ Seq(p.compile().classes, p.resources()))
     )
   }
 
-  def upstreamCompileDepClasspath = T{
-    Task.traverse(projectDeps.map(_.externalCompileDepClasspath))
-  }
-  def upstreamCompileDepSources = T{
-    Task.traverse(projectDeps.map(_.externalCompileDepSources))
-  }
-
   def upstreamCompileOutput = T{
-    Task.traverse(projectDeps.map(_.compile))
+    Task.traverse(projectDeps)(_.compile)
+  }
+  def upstreamCompileClasspath = T{
+    externalCompileDepClasspath() ++
+    upstreamCompileOutput().map(_.classes) ++
+    Task.traverse(projectDeps)(_.compileDepClasspath)().flatten
   }
 
   def resolveDeps(deps: Task[Seq[Dep]], sources: Boolean = false) = T.task{
@@ -105,13 +102,14 @@ trait ScalaModule extends Module with TaskModule{ outer =>
     )
   }
   def externalCompileDepClasspath: T[Seq[PathRef]] = T{
-    upstreamCompileDepClasspath().flatten ++
+    Task.traverse(projectDeps)(_.externalCompileDepClasspath)().flatten ++
     resolveDeps(
       T.task{ivyDeps() ++ compileIvyDeps() ++ scalaCompilerIvyDeps(scalaVersion())}
     )()
   }
+
   def externalCompileDepSources: T[Seq[PathRef]] = T{
-    upstreamCompileDepSources().flatten ++
+    Task.traverse(projectDeps)(_.externalCompileDepSources)().flatten ++
     resolveDeps(
       T.task{ivyDeps() ++ compileIvyDeps() ++ scalaCompilerIvyDeps(scalaVersion())},
       sources = true
@@ -122,9 +120,8 @@ trait ScalaModule extends Module with TaskModule{ outer =>
     * might be less than the runtime classpath
     */
   def compileDepClasspath: T[Seq[PathRef]] = T{
-    upstreamCompileOutput().map(_.classes) ++
-    depClasspath() ++
-    externalCompileDepClasspath()
+    upstreamCompileClasspath() ++
+    depClasspath()
   }
 
   /**
diff --git a/test.sh b/test.sh
new file mode 100755
index 00000000..ffae4a10
--- /dev/null
+++ b/test.sh
@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+
+set -eux
+
+# Starting from scratch...
+git clean -xdf
+
+# First build & run tests using SBT
+sbt core/test scalaplugin/test bin/test:assembly
+
+# Second build & run tests using Mill built using SBT
+bin/target/mill run Core.test
+bin/target/mill run ScalaPlugin.test
+bin/target/mill run assembly
+
+# Third build & run tests using Mill built using Mill
+out/assembly run Core.test
+out/assembly run ScalaPlugin.test
+out/assembly run assembly
\ No newline at end of file