scalapb-support-java-generation

Author: Armin Motekalem

contrib/scalapblib/src/mill/contrib/scalapblib/ScalaPBModule.scala

@@ -22,6 +22,8 @@ trait ScalaPBModule extends ScalaModule {
 
   def scalaPBVersion: T[String]
 
+  def scalaPBGenerators: T[Seq[Generator]] = Seq[Generator](ScalaGen)
+
   def scalaPBFlatPackage: T[Boolean] = Task { false }
 
   def scalaPBJavaConversions: T[Boolean] = Task { false }
@@ -141,7 +143,8 @@ trait ScalaPBModule extends ScalaModule {
         scalaPBSources().map(_.path),
         scalaPBOptions(),
         Task.dest,
-        scalaPBCompileOptions()
+        scalaPBCompileOptions(),
+        scalaPBGenerators()
       )
   }
 }

contrib/scalapblib/src/mill/contrib/scalapblib/ScalaPBWorker.scala

@@ -5,6 +5,7 @@ import java.io.File
 
 import mill.api.PathRef
 import mill.api.{Discover, ExternalModule}
+import upickle.default.ReadWriter
 
 class ScalaPBWorker {
 
@@ -15,16 +16,17 @@ class ScalaPBWorker {
           sources: Seq[File],
           scalaPBOptions: String,
           generatedDirectory: File,
-          otherArgs: Seq[String]
+          otherArgs: Seq[String],
+          generators: Seq[Generator]
       ): Unit = {
         val pbcClasspath = scalaPBClasspath.map(_.path).toVector
         mill.util.Jvm.withClassLoader(pbcClasspath, null) { cl =>
           val scalaPBCompilerClass = cl.loadClass("scalapb.ScalaPBC")
           val mainMethod = scalaPBCompilerClass.getMethod("main", classOf[Array[java.lang.String]])
-          val opts = if (scalaPBOptions.isEmpty) "" else scalaPBOptions + ":"
-          val args = otherArgs ++ Seq(
-            s"--scala_out=${opts}${generatedDirectory.getCanonicalPath}"
-          ) ++ roots.map(root => s"--proto_path=${root.getCanonicalPath}") ++ sources.map(
+          val args = otherArgs ++ generators.map { gen =>
+            val opts = if (scalaPBOptions.isEmpty || !gen.supportsScalaPBOptions) "" else scalaPBOptions + ":"
+            s"${gen.generator}=$opts${generatedDirectory.getCanonicalPath}"
+          } ++ roots.map(root => s"--proto_path=${root.getCanonicalPath}") ++ sources.map(
             _.getCanonicalPath
           )
           ctx.log.debug(s"ScalaPBC args: ${args.mkString(" ")}")
@@ -70,7 +72,8 @@ class ScalaPBWorker {
       scalaPBSources: Seq[os.Path],
       scalaPBOptions: String,
       dest: os.Path,
-      scalaPBCExtraArgs: Seq[String]
+      scalaPBCExtraArgs: Seq[String],
+      generators: Seq[Generator]
   )(implicit ctx: mill.api.TaskCtx): mill.api.Result[PathRef] = {
     val compiler = scalaPB(scalaPBClasspath)
     val sources = scalaPBSources.flatMap {
@@ -86,7 +89,7 @@ class ScalaPBWorker {
           Seq(ioFile)
     }
     val roots = scalaPBSources.map(_.toIO).filter(_.isDirectory)
-    compiler.compileScalaPB(roots, sources, scalaPBOptions, dest.toIO, scalaPBCExtraArgs)
+    compiler.compileScalaPB(roots, sources, scalaPBOptions, dest.toIO, scalaPBCExtraArgs, generators)
     mill.api.Result.Success(PathRef(dest))
   }
 }
@@ -97,10 +100,24 @@ trait ScalaPBWorkerApi {
       source: Seq[File],
       scalaPBOptions: String,
       generatedDirectory: File,
-      otherArgs: Seq[String]
+      otherArgs: Seq[String],
+      generators: Seq[Generator]
   ): Unit
 }
 
+sealed trait Generator derives ReadWriter {
+  def generator: String
+  def supportsScalaPBOptions: Boolean
+}
+case object ScalaGen extends Generator {
+  override def generator: String = "--scala_out"
+  override def supportsScalaPBOptions: Boolean = true
+}
+case object JavaGen extends Generator {
+  override def generator: String = "--java_out"
+  override def supportsScalaPBOptions: Boolean = false // Java options are specified directly in the proto file
+}
+
 object ScalaPBWorkerApi extends ExternalModule {
   def scalaPBWorker: Worker[ScalaPBWorker] = Task.Worker { new ScalaPBWorker() }
   lazy val millDiscover = Discover[this.type]

contrib/scalapblib/test/src/mill/contrib/scalapblib/TutorialTests.scala

@@ -11,7 +11,9 @@ import utest.{TestSuite, Tests, assert, *}
 object TutorialTests extends TestSuite {
   val testScalaPbVersion = "0.11.7"
 
-  trait TutorialBase extends TestRootModule
+  trait TutorialBase extends TestRootModule {
+    val core: TutorialModule
+  }
 
   trait TutorialModule extends ScalaPBModule {
     def scalaVersion = sys.props.getOrElse("TEST_SCALA_2_12_VERSION", ???)
@@ -70,19 +72,68 @@ object TutorialTests extends TestSuite {
     lazy val millDiscover = Discover[this.type]
   }
 
+  object TutorialWithJavaGen extends TutorialBase {
+    object core extends TutorialModule {
+      override def scalaPBGenerators = Seq(JavaGen)
+    }
+
+    lazy val millDiscover = Discover[this.type]
+  }
+
+  object TutorialWithScalaAndJavaGen extends TutorialBase {
+    object core extends TutorialModule {
+      override def scalaPBGenerators = Seq[Generator](ScalaGen, JavaGen)
+    }
+
+    lazy val millDiscover = Discover[this.type]
+  }
+
   val resourcePath: os.Path = os.Path(sys.env("MILL_TEST_RESOURCE_DIR"))
 
   def protobufOutPath(eval: UnitTester): os.Path =
     eval.outPath / "core/compileScalaPB.dest/com/example/tutorial"
 
-  def compiledSourcefiles: Seq[os.RelPath] = Seq[os.RelPath](
+  def compiledScalaSourcefiles: Seq[os.RelPath] = Seq[os.RelPath](
     os.rel / "AddressBook.scala",
     os.rel / "Person.scala",
     os.rel / "TutorialProto.scala",
     os.rel / "Include.scala",
     os.rel / "IncludeProto.scala"
   )
 
+  def compiledJavaSourcefiles: Seq[os.RelPath] = Seq[os.RelPath](
+    os.rel / "AddressBookProtos.java",
+    os.rel / "IncludeOuterClass.java"
+  )
+
+  // Helper function to test compilation with different generators
+  def testCompilation(
+    module: TutorialBase,
+    expectedFiles: Seq[os.RelPath]
+  ): Unit = {
+    UnitTester(module, resourcePath).scoped { eval =>
+      if (!mill.constants.Util.isWindows) {
+        val Right(result) = eval.apply(module.core.compileScalaPB): @unchecked
+
+        val outPath = protobufOutPath(eval)
+        val outputFiles = os.walk(result.value.path).filter(os.isFile)
+        val expectedSourcefiles = expectedFiles.map(outPath / _)
+
+        assert(
+          result.value.path == eval.outPath / "core/compileScalaPB.dest",
+          outputFiles.nonEmpty,
+          outputFiles.forall(expectedSourcefiles.contains),
+          outputFiles.size == outputFiles.size,
+          result.evalCount > 0
+        )
+
+        // don't recompile if nothing changed
+        val Right(result2) = eval.apply(module.core.compileScalaPB): @unchecked
+        assert(result2.evalCount == 0)
+      }
+    }
+  }
+
   def tests: Tests = Tests {
     test("scalapbVersion") {
 
@@ -97,30 +148,9 @@ object TutorialTests extends TestSuite {
     }
 
     test("compileScalaPB") {
-      test("calledDirectly") - UnitTester(Tutorial, resourcePath).scoped { eval =>
-        if (!mill.constants.Util.isWindows) {
-          val Right(result) = eval.apply(Tutorial.core.compileScalaPB): @unchecked
-
-          val outPath = protobufOutPath(eval)
-
-          val outputFiles = os.walk(result.value.path).filter(os.isFile)
-
-          val expectedSourcefiles = compiledSourcefiles.map(outPath / _)
-
-          assert(
-            result.value.path == eval.outPath / "core/compileScalaPB.dest",
-            outputFiles.nonEmpty,
-            outputFiles.forall(expectedSourcefiles.contains),
-            outputFiles.size == 5,
-            result.evalCount > 0
-          )
-
-          // don't recompile if nothing changed
-          val Right(result2) = eval.apply(Tutorial.core.compileScalaPB): @unchecked
-
-          assert(result2.evalCount == 0)
-        }
-      }
+      test("scalaGen") - testCompilation(Tutorial, compiledScalaSourcefiles)
+      test("javaGen") - testCompilation(TutorialWithJavaGen, compiledJavaSourcefiles)
+      test("scalaAndJavaGen") - testCompilation(TutorialWithScalaAndJavaGen, compiledScalaSourcefiles ++ compiledJavaSourcefiles)
 
       test("calledWithSpecificFile") - UnitTester(
         TutorialWithSpecificSources,
@@ -165,7 +195,7 @@ object TutorialTests extends TestSuite {
 //
 //      //   val outputFiles = os.walk(outPath).filter(_.isFile)
 //
-//      //   val expectedSourcefiles = compiledSourcefiles.map(outPath / _)
+//      //   val expectedSourcefiles = compiledScalaSourcefiles.map(outPath / _)
 //
 //      //   assert(
 //      //     outputFiles.nonEmpty,