Only compile 2.13 library in stdlib-bootstrapped

Author: nicolasstucki

project/Build.scala

@@ -922,23 +922,19 @@ object Build {
       javaOptions := (`scala3-compiler-bootstrapped` / javaOptions).value
     )
 
-  /** Scala library compiled by dotty using the latest published sources of the library */
+  /** Scala 2 library compiled by dotty using the latest published sources of the library.
+   *
+   *  This version of the library is not (yet) TASTy/binary compatible with the Scala 2 compiled library.
+   */
   lazy val `stdlib-bootstrapped` = project.in(file("stdlib-bootstrapped")).
     withCommonSettings(Bootstrapped).
     dependsOn(dottyCompiler(Bootstrapped) % "provided; compile->runtime; test->test").
     settings(commonBootstrappedSettings).
     settings(
       moduleName := "scala-library",
       javaOptions := (`scala3-compiler-bootstrapped` / javaOptions).value,
-      Compile/scalacOptions += "-Yerased-terms",
-      Compile/scalacOptions ++= {
-        Seq(
-          "-sourcepath",
-          Seq(
-            (Compile/sourceManaged).value / "scala-library-src",
-            (Compile/sourceManaged).value / "dotty-library-src",
-          ).mkString(File.pathSeparator),
-        )
+      Compile / scalacOptions ++= {
+        Seq("-sourcepath", ((Compile/sourceManaged).value / "scala-library-src").toString)
       },
       Compile / doc / scalacOptions += "-Ydocument-synthetic-types",
       scalacOptions -= "-Xfatal-warnings",
@@ -970,36 +966,6 @@ object Build {
           ((trgDir ** "*.scala") +++ (trgDir ** "*.java")).get.toSet
         } (Set(scalaLibrarySourcesJar)).toSeq
       }.taskValue,
-      (Compile / sourceGenerators) += Def.task {
-        val s = streams.value
-        val cacheDir = s.cacheDirectory
-        val trgDir = (Compile / sourceManaged).value / "dotty-library-src"
-
-        // NOTE `sourceDirectory` is used for actual copying,
-        // but `sources` are used as cache keys
-        val dottyLibSourceDirs = (`scala3-library-bootstrapped`/Compile/unmanagedSourceDirectories).value
-        def dottyLibSources = dottyLibSourceDirs.foldLeft(PathFinder.empty) { (pf, dir) =>
-          if (!dir.exists) pf else pf +++ (dir ** "*.scala") +++ (dir ** "*.java")
-        }
-
-        val cachedFun = FileFunction.cached(
-          cacheDir / s"copyDottyLibrarySrc",
-          FilesInfo.lastModified,
-          FilesInfo.exists,
-        ) { _ =>
-          if (trgDir.exists) IO.delete(trgDir)
-          dottyLibSourceDirs.foreach { dir =>
-            if (dir.exists) {
-              s.log.info(s"Copying scala3-library sources from $dir to $trgDir...")
-              IO.copyDirectory(dir, trgDir)
-            }
-          }
-
-          ((trgDir ** "*.scala") +++ (trgDir ** "*.java")).get.toSet
-        }
-
-        cachedFun(dottyLibSources.get.toSet).toSeq
-      }.taskValue,
       (Compile / sources) ~= (_.filterNot(file =>
         // sources from https://github.com/scala/scala/tree/2.13.x/src/library-aux
         file.getPath.endsWith("scala-library-src/scala/Any.scala") ||
@@ -1011,7 +977,7 @@ object Build {
       (Test / managedClasspath) ~= {
         _.filterNot(file => file.data.getName == s"scala-library-${stdlibVersion(Bootstrapped)}.jar")
       },
-    )
+  )
 
   /** Test the tasty generated by `stdlib-bootstrapped`
    *

stdlib-bootstrapped/test/Main.scala

@@ -5,7 +5,7 @@ enum Color:
 
 object HelloWorld:
   def main(args: Array[String]): Unit = {
-    println("hello dotty.superbootstrapped!")
+    println("hello 2.13 library bootstrapped")
     println(Color.Red)
     println(Color.Green)
     println(Color.Blue)