Add scala2-library-cc-tasty project

We can override the sources of the standard library with cc annotation
in this project and generate a TASTy version of the standard library.

Author: nicolasstucki

.github/workflows/ci.yaml

@@ -145,6 +145,9 @@ jobs:
       - name: Test with Scala 2 library TASTy
         run: ./project/scripts/sbt ";set ThisBuild/Build.useScala2LibraryTasty := true ;scala3-bootstrapped/testCompilation i5; scala3-bootstrapped/testCompilation tests/run/typelevel-peano.scala" # only test a subset of test to avoid doubling the CI execution time
 
+      - name: Test with Scala 2 library TASTy with CC
+        run: ./project/scripts/sbt ";set ThisBuild/Build.useScala2LibraryCCTasty := true ;scala3-bootstrapped/testCompilation i5; scala3-bootstrapped/testCompilation tests/run/typelevel-peano.scala" # only test a subset of test to avoid doubling the CI execution time
+
   test_windows_fast:
     runs-on: [self-hosted, Windows]
     if: "(
@@ -256,7 +259,7 @@ jobs:
 
       - name: MiMa
         run: |
-          ./project/scripts/sbt ";scala3-interfaces/mimaReportBinaryIssues ;scala3-library-bootstrapped/mimaReportBinaryIssues ;scala3-library-bootstrappedJS/mimaReportBinaryIssues; tasty-core-bootstrapped/mimaReportBinaryIssues; scala2-library-bootstrapped/mimaReportBinaryIssues"
+          ./project/scripts/sbt ";scala3-interfaces/mimaReportBinaryIssues ;scala3-library-bootstrapped/mimaReportBinaryIssues ;scala3-library-bootstrappedJS/mimaReportBinaryIssues; tasty-core-bootstrapped/mimaReportBinaryIssues; scala2-library-bootstrapped/mimaReportBinaryIssues; scala2-library-cc/mimaReportBinaryIssues"
 
       - name: TASTy MiMa
         run: |

build.sbt

@@ -17,6 +17,8 @@ val `scala3-bench-micro` = Build.`scala3-bench-micro`
 val `scala2-library-bootstrapped` = Build.`scala2-library-bootstrapped`
 val `scala2-library-tasty` = Build.`scala2-library-tasty`
 val `scala2-library-tasty-tests` = Build.`scala2-library-tasty-tests`
+val `scala2-library-cc` = Build.`scala2-library-cc`
+val `scala2-library-cc-tasty` = Build.`scala2-library-cc-tasty`
 val `tasty-core` = Build.`tasty-core`
 val `tasty-core-bootstrapped` = Build.`tasty-core-bootstrapped`
 val `tasty-core-scala2` = Build.`tasty-core-scala2`

project/Build.scala

@@ -176,9 +176,15 @@ object Build {
   // Use the TASTy jar from `scala2-library-tasty` in the classpath
   // This only works with `scala3-bootstrapped/scalac` and tests in `scala3-bootstrapped`
   //
-  // Enable in SBT with: set ThisBuild/Build.useScala2LibraryTasty := true
+  // Enable in SBT with: `set ThisBuild/Build.useScala2LibraryTasty := true`
   val useScala2LibraryTasty = settingKey[Boolean]("Use the TASTy jar from `scala2-library-tasty` in the classpath")
 
+  // Use the TASTy jar from `scala2-library-cc-tasty` in the classpath
+  // This only works with `scala3-bootstrapped/scalac` and tests in `scala3-bootstrapped`
+  //
+  // Enable in SBT with: `set ThisBuild/Build.useScala2LibraryCCTasty := true`
+  val useScala2LibraryCCTasty = settingKey[Boolean]("Use the TASTy jar from `scala2-library-cc-tasty` in the classpath")
+
   // Used to compile files similar to ./bin/scalac script
   val scalac = inputKey[Unit]("run the compiler using the correct classpath, or the user supplied classpath")
 
@@ -226,6 +232,7 @@ object Build {
     outputStrategy := Some(StdoutOutput),
 
     useScala2LibraryTasty := false,
+    useScala2LibraryCCTasty := false,
 
     // enable verbose exception messages for JUnit
     (Test / testOptions) += Tests.Argument(TestFrameworks.JUnit, "-a", "-v", "-s"),
@@ -653,7 +660,18 @@ object Build {
             Seq.empty
         }
 
-        scala2LibraryTasty ++ Seq(
+        val scala2LibraryCCTasty = jars.get("scala2-library-cc-tasty") match {
+          case Some(scala2LibraryCCTastyJar) if useScala2LibraryCCTasty.value =>
+            if (useScala2LibraryTasty.value) {
+              log.warn("Both useScala2LibraryTasty and useScala2LibraryCCTasty are set (ignoring useScala2LibraryCCTasty)")
+              Seq.empty
+            } else Seq("-Ddotty.tests.tasties.scalaLibrary=" + scala2LibraryCCTastyJar)
+          case _ =>
+            if (useScala2LibraryCCTasty.value) log.warn("useScala2LibraryCCTasty is ignored on non-bootstrapped compiler")
+            Seq.empty
+        }
+
+        scala2LibraryTasty ++ scala2LibraryCCTasty ++ Seq(
           "-Ddotty.tests.dottyCompilerManagedSources=" + managedSrcDir,
           "-Ddotty.tests.classes.dottyInterfaces=" + jars("scala3-interfaces"),
           "-Ddotty.tests.classes.dottyLibrary=" + jars("scala3-library"),
@@ -876,6 +894,7 @@ object Build {
         "scala3-tasty-inspector"  -> (LocalProject("scala3-tasty-inspector") / Compile / packageBin).value.getAbsolutePath,
         "tasty-core"     -> (LocalProject("tasty-core-bootstrapped") / Compile / packageBin).value.getAbsolutePath,
         "scala2-library-tasty" -> (LocalProject("scala2-library-tasty") / Compile / packageBin).value.getAbsolutePath,
+        "scala2-library-cc-tasty" -> (LocalProject("scala2-library-cc-tasty") / Compile / packageBin).value.getAbsolutePath,
       )
     },
 
@@ -1004,8 +1023,21 @@ object Build {
     withCommonSettings(Bootstrapped).
     dependsOn(dottyCompiler(Bootstrapped) % "provided; compile->runtime; test->test").
     settings(commonBootstrappedSettings).
-    settings(
-      moduleName := "scala2-library",
+    settings(scala2LibraryBootstrappedSettings).
+    settings(moduleName := "scala2-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 `scala2-library-cc` = project.in(file("scala2-library-cc")).
+    withCommonSettings(Bootstrapped).
+    dependsOn(dottyCompiler(Bootstrapped) % "provided; compile->runtime; test->test").
+    settings(commonBootstrappedSettings).
+    settings(scala2LibraryBootstrappedSettings).
+    settings(moduleName := "scala2-library-cc")
+
+  lazy val scala2LibraryBootstrappedSettings = Seq(
       javaOptions := (`scala3-compiler-bootstrapped` / javaOptions).value,
       Compile / scalacOptions ++= {
         Seq("-sourcepath", ((Compile/sourceManaged).value / "scala-library-src").toString)
@@ -1088,13 +1120,13 @@ object Build {
              |   - final val MinorVersion = $minorVersion
              |   - final val ExperimentalVersion = 0
              | * Clean everything to generate a compiler with those new TASTy versions
-             | * Run scala2-library-bootstrapped/tastyMiMaReportIssues
+             | * Run ${name.value}/tastyMiMaReportIssues
              |""".stripMargin)
 
       }).value,
       Compile / exportJars := true,
       artifactName := { (sv: ScalaVersion, module: ModuleID, artifact: Artifact) =>
-        "scala2-library-" + dottyVersion + "." + artifact.extension
+        moduleName.value + "-" + dottyVersion + "." + artifact.extension
       },
       run := {
         val log = streams.value.log
@@ -1132,18 +1164,18 @@ object Build {
             println(
               s"""Usage:
                 |> $projectName/run list
-                |  -- lists all files that are not overriden in scala2-library-bootstrapped/src
+                |  -- lists all files that are not overriden in ${name.value}/src
                 |
                 |> $projectName/run clone <sources>*
-                |  -- clones the specified sources from the scala2-library-bootstrapped/src
+                |  -- clones the specified sources from the ${name.value}/src
                 |  -- example: $projectName/run clone scala/Option.scala
                 |
                 |> $projectName/run overwrite <sources>*
-                |  -- (danger) overwrites the specified sources from the scala2-library-bootstrapped/src
+                |  -- (danger) overwrites the specified sources from the ${name.value}/src
                 |""".stripMargin)
         }
       }
-    )
+  )
 
   /** Packages the TASTy files of `scala2-library-bootstrapped` in a jar */
   lazy val `scala2-library-tasty` = project.in(file("scala2-library-tasty")).
@@ -1156,6 +1188,17 @@ object Build {
       },
     )
 
+  /** Packages the TASTy files of `scala2-library-cc` in a jar */
+  lazy val `scala2-library-cc-tasty` = project.in(file("scala2-library-cc-tasty")).
+    withCommonSettings(Bootstrapped).
+    settings(
+      exportJars := true,
+      Compile / packageBin / mappings := {
+        (`scala2-library-cc` / Compile / packageBin / mappings).value
+          .filter(_._2.endsWith(".tasty"))
+      },
+    )
+
   /** Test the tasty generated by `scala2-library-bootstrapped`
    *
    *  The sources in src are compiled using TASTy from scala2-library-tasty but then run

project/scripts/scala2-library-tasty-mima.sh

@@ -20,4 +20,7 @@ setTastyVersion $MINOR_TASTY_VERSION_SUPPORTED_BY_TASTY_MIMA 0
 # We set -Ycheck:all to check that -Ycompile-scala2-library does not gererate inconsistent trees.
 "$SBT" 'clean; scala2-library-bootstrapped/clean; reload; set `scala2-library-bootstrapped`/scalacOptions += "-Ycheck:all"; scala2-library-bootstrapped/tastyMiMaReportIssues; clean; scala2-library-bootstrapped/clean'
 
+# Do the same tests with scala2-library-cc
+"$SBT" 'clean; scala2-library-cc/clean; reload; set `scala2-library-cc`/scalacOptions += "-Ycheck:all"; scala2-library-cc/tastyMiMaReportIssues; clean; scala2-library-cc/clean'
+
 setTastyVersion $MINOR_TASTY_VERSION $EXPERIMENTAL_TASTY_VERSION