Merge pull request #5835 from dotty-staging/sbt-dotty-0.3.0

sbt-dotty: Rework classpath and ScalaInstance handling, fix minimum sbt version check, release 0.3.0

Author: smarter

project/Build.scala

@@ -16,6 +16,7 @@ import xerial.sbt.pack.PackPlugin
 import xerial.sbt.pack.PackPlugin.autoImport._
 
 import dotty.tools.sbtplugin.DottyPlugin.autoImport._
+import dotty.tools.sbtplugin.DottyPlugin.makeScalaInstance
 import dotty.tools.sbtplugin.DottyIDEPlugin.{ installCodeExtension, prepareCommand, runProcess }
 import dotty.tools.sbtplugin.DottyIDEPlugin.autoImport._
 
@@ -27,20 +28,11 @@ import sbtbuildinfo.BuildInfoPlugin.autoImport._
 
 import scala.util.Properties.isJavaAtLeast
 
-/* In sbt 0.13 the Build trait would expose all vals to the shell, where you
- * can use them in "set a := b" like expressions. This re-exposes them.
- */
-object ExposedValues extends AutoPlugin {
-  object autoImport {
-    val bootstrapFromPublishedJars = Build.bootstrapFromPublishedJars
-  }
-}
-
 object Build {
   val scalacVersion = "2.12.8"
 
   val baseVersion = "0.13.0"
-  val baseSbtDottyVersion = "0.2.7"
+  val baseSbtDottyVersion = "0.3.1"
 
   // Versions used by the vscode extension to create a new project
   // This should be the latest published releases.
@@ -100,8 +92,6 @@ object Build {
   // Shorthand for compiling a docs site
   val dottydoc = inputKey[Unit]("run dottydoc")
 
-  val bootstrapFromPublishedJars = settingKey[Boolean]("If true, bootstrap dotty from published non-bootstrapped dotty")
-
   // Only available in vscode-dotty
   val unpublish = taskKey[Unit]("Unpublish a package")
 
@@ -129,9 +119,6 @@ object Build {
 
     javacOptions in (Compile, compile) ++= Seq("-Xlint:unchecked", "-Xlint:deprecation"),
 
-    // Change this to true if you want to bootstrap using a published non-bootstrapped compiler
-    bootstrapFromPublishedJars := false,
-
     // Override `runCode` from sbt-dotty to use the language-server and
     // vscode extension from the source repository of dotty instead of a
     // published version.
@@ -220,20 +207,6 @@ object Build {
     // Use the same name as the non-bootstrapped projects for the artifacts
     moduleName ~= { _.stripSuffix("-bootstrapped") },
 
-    // Prevent sbt from setting the Scala bootclasspath, otherwise it will
-    // contain `scalaInstance.value.libraryJar` which in our case is the
-    // non-bootstrapped dotty-library that will then take priority over
-    // the bootstrapped dotty-library on the classpath or sourcepath.
-    classpathOptions ~= (_.withAutoBoot(false)),
-    // ... but when running under Java 8, we still need a Scala bootclasspath that contains the JVM bootclasspath,
-    // otherwise sbt incremental compilation breaks.
-    scalacOptions ++= {
-      if (isJavaAtLeast("9"))
-        Seq()
-      else
-        Seq("-bootclasspath", sys.props("sun.boot.class.path"))
-    },
-
     // Enforce that the only Scala 2 classfiles we unpickle come from scala-library
     /*
     scalacOptions ++= {
@@ -251,64 +224,31 @@ object Build {
     // ...but scala-library is
     libraryDependencies += "org.scala-lang" % "scala-library" % scalacVersion,
 
-    ivyConfigurations ++= {
-      if (bootstrapFromPublishedJars.value)
-        Seq(Configurations.ScalaTool)
-      else
-        Seq()
-    },
-    libraryDependencies ++= {
-      if (bootstrapFromPublishedJars.value)
-        Seq(
-          dottyOrganization %% "dotty-library" % dottyNonBootstrappedVersion % Configurations.ScalaTool.name,
-          dottyOrganization %% "dotty-compiler" % dottyNonBootstrappedVersion % Configurations.ScalaTool.name
-        ).map(_.withDottyCompat(scalaVersion.value))
-      else
-        Seq()
-    },
-
     // Compile using the non-bootstrapped and non-published dotty
     managedScalaInstance := false,
     scalaInstance := {
-      import sbt.internal.inc.ScalaInstance
-      import sbt.internal.inc.classpath.ClasspathUtilities
-
-      val updateReport = update.value
-      var libraryJar = packageBin.in(`dotty-library`, Compile).value
-      var compilerJar = packageBin.in(`dotty-compiler`, Compile).value
-
-      if (bootstrapFromPublishedJars.value) {
-        val jars = updateReport.select(
-            configuration = configurationFilter(Configurations.ScalaTool.name),
-            module = moduleFilter(),
-            artifact = artifactFilter(extension = "jar")
-          )
-        libraryJar = jars.find(_.getName.startsWith("dotty-library_2.12")).get
-        compilerJar = jars.find(_.getName.startsWith("dotty-compiler_2.12")).get
-      }
-
-      // All dotty-doc's and compiler's dependencies except the library.
-      // (we get the compiler's dependencies because dottydoc depends on the compiler)
-      val otherDependencies = {
-        val excluded = Set("dotty-library", "dotty-compiler")
-        fullClasspath.in(`dotty-doc`, Compile).value
-          .filterNot(_.get(artifact.key).exists(a => excluded.contains(a.name)))
-          .map(_.data)
-      }
-
-      val allJars = libraryJar :: compilerJar :: otherDependencies.toList
-      val classLoader = state.value.classLoaderCache(allJars)
-      new ScalaInstance(
+      // TODO: Here we use the output class directories directly, this might impact
+      // performance when running the compiler (especially on Windows where file
+      // IO is slow). We should benchmark whether using jars is actually faster
+      // in practice (especially on our CI), this could be done using
+      // `exportJars := true`.
+      val all = fullClasspath.in(`dotty-doc`, Compile).value
+      def getArtifact(name: String): File =
+        all.find(_.get(artifact.key).exists(_.name == name))
+          .getOrElse(throw new MessageOnlyException(s"Artifact for $name not found in $all"))
+          .data
+
+      val scalaLibrary = getArtifact("scala-library")
+      val dottyLibrary = getArtifact("dotty-library")
+      val compiler = getArtifact("dotty-compiler")
+
+      makeScalaInstance(
+        state.value,
         scalaVersion.value,
-        classLoader,
-        ClasspathUtilities.rootLoader, // FIXME: Should be a class loader which only includes the dotty-lib
-                                       // See: https://github.com/sbt/zinc/commit/9397b6aaf94ac3cfab386e3abd11c0ef9c2ceaff#diff-ea135f2f26f43e40ff045089da221e1e
-                                       // Should not matter, as it addresses an issue with `sbt run` that
-                                       // only occur when `(fork in run) := false`
-        libraryJar,
-        compilerJar,
-        allJars.toArray,
-        None
+        scalaLibrary,
+        dottyLibrary,
+        compiler,
+        all.map(_.data)
       )
     }
   )
@@ -334,11 +274,6 @@ object Build {
 
   /** Projects -------------------------------------------------------------- */
 
-  // Needed because the dotty project aggregates dotty-sbt-bridge but dotty-sbt-bridge
-  // currently refers to dotty in its scripted task and "aggregate" does not take by-name
-  // parameters: https://github.com/sbt/sbt/issues/2200
-  lazy val dottySbtBridgeRef = LocalProject("dotty-sbt-bridge")
-
   // The root project:
   // - aggregates other projects so that "compile", "test", etc are run on all projects at once.
   // - publishes its own empty artifact "dotty" that depends on "dotty-library" and "dotty-compiler",