Cleanup and Testcase for targetBytecode and previewEnabled

Author: lostiniceland

libs/groovylib/package.mill

@@ -11,6 +11,10 @@ object `package` extends MillPublishScalaModule with BuildInfo {
   def localTestExtraModules: Seq[MillJavaModule] =
     super.localTestExtraModules ++ Seq(worker)
 
+  override def testMvnDeps: T[Seq[Dep]] = super.testMvnDeps() ++ Seq(
+    Deps.asmTree
+  )
+  
   def buildInfoPackageName = "mill.groovylib"
   def buildInfoObjectName = "Versions"
   def buildInfoMembers = Seq(

libs/groovylib/src/mill/groovylib/GroovyModule.scala

@@ -174,24 +174,17 @@ trait GroovyModule extends JavaModule with GroovyModuleApi { outer =>
         )
       }
 
-      if (isMixed) {
+      def compileGroovyStubs(): Result[CompilationResult] = {
         ctx.log.info("Compiling Groovy stubs for mixed compilation")
-
-        val workerStubResult =
-          GroovyWorkerManager.groovyWorker().withValue(groovyCompilerClasspath()) {
-            _.compileGroovyStubs(groovySourceFiles, compileCp, classes, config)
-          }
-        workerStubResult match {
-          case Result.Success(_) => compileJava
-          case Result.Failure(reason) => Result.Failure(reason)
+        GroovyWorkerManager.groovyWorker().withValue(groovyCompilerClasspath()) {
+          _.compileGroovyStubs(groovySourceFiles, compileCp, classes, config)
         }
       }
 
-      if (isMixed || isGroovy) {
+      def compileGroovy(): Result[CompilationResult] = {
         ctx.log.info(
           s"Compiling ${groovySourceFiles.size} Groovy sources to $classes ..."
         )
-
         val workerGroovyResult =
           GroovyWorkerManager.groovyWorker().withValue(groovyCompilerClasspath()) {
             _.compile(groovySourceFiles, compileCp, classes, config)
@@ -206,6 +199,17 @@ trait GroovyModule extends JavaModule with GroovyModuleApi { outer =>
             CompilationResult(analysisFile, PathRef(classes))
           case Result.Failure(reason) => Result.Failure(reason)
         }
+      }
+
+      val firstAndSecondStage = if (isMixed) {
+        // only compile Java if Stubs are successfully generated
+        compileGroovyStubs().flatMap(_ => compileJava)
+      }else{
+        Result.Success
+      }
+
+      if (isMixed || isGroovy) {
+        firstAndSecondStage.flatMap(_ => compileGroovy())
       } else {
         compileJava
       }

libs/groovylib/test/resources/hello-groovy/main/compileroptions/src/HelloCompilerOptions.groovy

@@ -0,0 +1,12 @@
+package compileroptions
+
+class HelloCompilerOptions {
+
+    static String getHelloString() {
+        return "Hello, Java 11 Preview!"
+    }
+
+    static void main(String[] args) {
+        println(getHelloString())
+    }
+}

libs/groovylib/test/src/mill/groovylib/HelloGroovyTests.scala

@@ -7,6 +7,8 @@ import mill.api.Discover
 import mill.testkit.{TestRootModule, UnitTester}
 import utest.*
 
+import java.io.FileInputStream
+
 object HelloGroovyTests extends TestSuite {
 
   val groovy4Version = "4.0.28"
@@ -101,6 +103,13 @@ object HelloGroovyTests extends TestSuite {
         override def jupiterVersion: T[String] = junit5Version
         override def junitPlatformVersion = "1.13.4"
       }
+      
+      object compileroptions extends GroovyModule {
+        override def groovyVersion: T[String] = crossValue
+        override def targetBytecode: Task.Simple[Option[String]] = Some("11")
+        override def enablePreview: Task.Simple[Boolean] = true
+        override def mainClass = Some("compileroptions.HelloCompilerOptions")
+      }
     }
     object main extends Cross[Test](groovyVersions)
   }
@@ -195,6 +204,49 @@ object HelloGroovyTests extends TestSuite {
       }
     }
 
+    test("compiles to Java 11 with Preview enabled") {
+      import org.objectweb.asm.ClassReader
+
+      case class BytecodeVersion(major: Int, minor: Int) {
+        def javaVersion: String = major match {
+          case 55 => "11"
+          case _ => "Irrelevant"
+        }
+
+        def is11PreviewEnabled: Boolean = minor == 65535 // 0xFFFF
+      }
+
+      def getBytecodeVersion(classFilePath: os.Path): BytecodeVersion = {
+        val classReader = new ClassReader(new FileInputStream(classFilePath.toIO))
+        val buffer = classReader.b
+
+        // Class file format: magic(4) + minor(2) + major(2) + ...
+        val minor = ((buffer(4) & 0xFF) << 8) | (buffer(5) & 0xFF)
+        val major = ((buffer(6) & 0xFF) << 8) | (buffer(7) & 0xFF)
+
+        BytecodeVersion(major, minor)
+      }
+
+      testEval().scoped { eval =>
+        main.crossModules.foreach(m => {
+          val Right(result) = eval.apply(m.compileroptions.compile): @unchecked
+
+          val compiledClassFile = os.walk(result.value.classes.path).find(_.last == "HelloCompilerOptions.class")
+          
+          assert(
+            compiledClassFile.isDefined
+          )
+
+          val bytecodeVersion = getBytecodeVersion(compiledClassFile.get)
+
+          assert(bytecodeVersion.major == 55)
+          assert(bytecodeVersion.is11PreviewEnabled)
+          
+          val Right(_) = eval.apply(m.compileroptions.run()): @unchecked
+        })
+      }
+    }
+
     test("compile & test module (only test uses Groovy)") {
       testEval().scoped { eval =>