feat: Cross build for Scala 3 for CSV and Cassandra (#2957)

.github/workflows/check-build-test.yml

@@ -41,8 +41,8 @@ jobs:
       - name: Cache Coursier cache
         uses: coursier/[email protected]
 
-      - name: "Code style, compile tests, MiMa. Run locally with: sbt +~2.13 \"verifyCodeStyle; Test/compile; mimaReportBinaryIssues\""
-        run: sbt +~2.13 "verifyCodeStyle; Test/compile; mimaReportBinaryIssues"
+      - name: "Code style, compile tests, MiMa. Run locally with: sbt \"verifyCodeStyle; +Test/compile; mimaReportBinaryIssues\""
+        run: sbt "verifyCodeStyle; +Test/compile; mimaReportBinaryIssues"
 
   documentation:
     name: ScalaDoc, Documentation with Paradox

build.sbt

@@ -131,11 +131,12 @@ lazy val azureStorageQueue = alpakkaProject(
 
 lazy val cassandra =
   alpakkaProject("cassandra", "cassandra", Dependencies.Cassandra)
+    .settings(Scala3.settings)
 
 lazy val couchbase =
   alpakkaProject("couchbase", "couchbase", Dependencies.Couchbase)
 
-lazy val csv = alpakkaProject("csv", "csv")
+lazy val csv = alpakkaProject("csv", "csv").settings(Scala3.settings)
 
 lazy val csvBench = internalProject("csv-bench")
   .dependsOn(csv)
@@ -444,6 +445,7 @@ lazy val docs = project
   )
 
 lazy val testkit = internalProject("testkit", Dependencies.testkit)
+  .settings(Scala3.settings) // needed for modules that depend on testKit, e.g. csv
 
 lazy val `doc-examples` = project
   .enablePlugins(AutomateHeaderPlugin)

cassandra/src/main/scala/akka/stream/alpakka/cassandra/javadsl/CassandraSession.scala

@@ -74,7 +74,7 @@ final class CassandraSession(@InternalApi private[akka] val delegate: scaladsl.C
            onClose: java.lang.Runnable) =
     this(system.classicSystem, sessionProvider, executionContext, log, metricsCategory, init, onClose)
 
-  implicit private val ec = delegate.ec
+  implicit private val ec: ExecutionContext = delegate.ec
 
   /**
    * Closes the underlying Cassandra session.

cassandra/src/test/scala/akka/stream/alpakka/cassandra/scaladsl/CassandraSessionPerformanceSpec.scala

@@ -15,7 +15,7 @@ import scala.concurrent.duration._
 
 final class CassandraSessionPerformanceSpec extends CassandraSpecBase(ActorSystem("CassandraSessionPerformanceSpec")) {
 
-  val log = Logging(system, this.getClass)
+  val log = Logging(system, this.getClass.asInstanceOf[Class[Any]])
 
   val data = 1 to 5 * 1000 * 1000
 

cassandra/src/test/scala/docs/javadsl/CassandraSessionSpec.scala

@@ -28,7 +28,7 @@ import scala.concurrent.duration._
 
 final class CassandraSessionSpec extends CassandraSpecBase(ActorSystem("CassandraSessionSpec")) {
 
-  val log = Logging(system, this.getClass)
+  val log = Logging(system, this.getClass.asInstanceOf[Class[Any]])
   val javadslSessionRegistry = javadsl.CassandraSessionRegistry.get(system)
 
   val data = 1 until 103

csv/src/test/scala/docs/scaladsl/CsvParsingSpec.scala

@@ -5,10 +5,10 @@
 package docs.scaladsl
 
 import java.nio.file.Paths
-
 import akka.NotUsed
 import akka.stream.alpakka.csv.scaladsl.{CsvParsing, CsvToMap}
 import akka.stream.scaladsl.{FileIO, Flow, Keep, Sink, Source}
+import akka.stream.testkit.{TestPublisher, TestSubscriber}
 import akka.stream.testkit.scaladsl.StreamTestKit.assertAllStagesStopped
 import akka.stream.testkit.scaladsl.{TestSink, TestSource}
 import akka.util.ByteString
@@ -120,7 +120,7 @@ class CsvParsingSpec extends CsvSpec {
     }
 
     "emit completion even without new line at end" in assertAllStagesStopped {
-      val (source, sink) = TestSource[ByteString]()
+      val (source: TestPublisher.Probe[ByteString], sink: TestSubscriber.Probe[List[String]]) = TestSource[ByteString]()
         .via(CsvParsing.lineScanner())
         .map(_.map(_.utf8String))
         .toMat(TestSink[List[String]]())(Keep.both)

csv/src/test/scala/docs/scaladsl/CsvSpec.scala

@@ -4,7 +4,8 @@
 
 package docs.scaladsl
 
-import akka.actor.ActorSystem
+import akka.actor.{ActorSystem, ClassicActorSystemProvider}
+import akka.stream.Materializer
 import akka.stream.alpakka.testkit.scaladsl.LogCapturing
 import akka.testkit.TestKit
 import org.scalatest.concurrent.ScalaFutures
@@ -20,7 +21,9 @@ abstract class CsvSpec
     with ScalaFutures
     with LogCapturing {
 
-  implicit val system = ActorSystem(this.getClass.getSimpleName)
+  implicit val system: ActorSystem = ActorSystem(this.getClass.getSimpleName)
+  implicit val classic: ClassicActorSystemProvider = system
+  implicit val mat: Materializer = Materializer(system)
 
   override protected def afterAll(): Unit =
     TestKit.shutdownActorSystem(system)

mongodb/src/test/scala/docs/scaladsl/MongoSinkSpec.scala

@@ -54,7 +54,7 @@ class MongoSinkSpec
   private val domainObjectsDocumentColl = db.getCollection("domainObjectsSink")
 
   implicit val defaultPatience =
-    PatienceConfig(timeout = 5.seconds, interval = 50.millis)
+    PatienceConfig(timeout = 10.seconds, interval = 100.millis)
 
   override def afterEach(): Unit = {
     Source.fromPublisher(numbersDocumentColl.deleteMany(new Document())).runWith(Sink.head).futureValue

project/Common.scala

@@ -41,7 +41,7 @@ object Common extends AutoPlugin {
   override lazy val projectSettings = Dependencies.Common ++ Seq(
       projectInfoVersion := (if (isSnapshot.value) "snapshot" else version.value),
       crossVersion := CrossVersion.binary,
-      crossScalaVersions := Dependencies.ScalaVersions,
+      crossScalaVersions := Dependencies.Scala2Versions,
       scalaVersion := Dependencies.Scala213,
       scalacOptions ++= Seq(
           "-encoding",
@@ -55,7 +55,8 @@ object Common extends AutoPlugin {
           "8"
         ),
       scalacOptions ++= (scalaVersion.value match {
-          case Dependencies.Scala213 if insideCI.value && fatalWarnings.value && !Dependencies.CronBuild =>
+          case Dependencies.Scala213
+              if insideCI.value && fatalWarnings.value && !Dependencies.CronBuild && scalaVersion.value != Dependencies.Scala3 =>
             Seq("-Werror")
           case _ => Seq.empty[String]
         }),
@@ -65,14 +66,20 @@ object Common extends AutoPlugin {
           "-doc-version",
           version.value,
           "-sourcepath",
-          (ThisBuild / baseDirectory).value.toString,
-          "-skip-packages",
-          "akka.pattern:" + // for some reason Scaladoc creates this
-          "org.mongodb.scala:" + // this one is a mystery as well
+          (ThisBuild / baseDirectory).value.toString
+        ) ++ {
           // excluding generated grpc classes, except the model ones (com.google.pubsub)
-          "com.google.api:com.google.cloud:com.google.iam:com.google.logging:" +
-          "com.google.longrunning:com.google.protobuf:com.google.rpc:com.google.type"
-        ),
+          val skip = "akka.pattern:" + // for some reason Scaladoc creates this
+            "org.mongodb.scala:" + // this one is a mystery as well
+            // excluding generated grpc classes, except the model ones (com.google.pubsub)
+            "com.google.api:com.google.cloud:com.google.iam:com.google.logging:" +
+            "com.google.longrunning:com.google.protobuf:com.google.rpc:com.google.type"
+          if (scalaBinaryVersion.value.startsWith("3")) {
+            Seq(s"-skip-packages:$skip") // different usage in scala3
+          } else {
+            Seq("-skip-packages", skip)
+          }
+        },
       Compile / doc / scalacOptions ++=
         Seq(
           "-doc-source-url", {

project/Dependencies.scala

@@ -7,7 +7,9 @@ object Dependencies {
 
   val Scala213 = "2.13.10" // update even in link-validator.conf
   val Scala212 = "2.12.17"
-  val ScalaVersions = Seq(Scala213, Scala212)
+  val Scala3 = "3.1.3"
+  val Scala2Versions = Seq(Scala213, Scala212)
+  val ScalaVersions = Dependencies.Scala2Versions :+ Dependencies.Scala3
 
   val AkkaVersion = "2.7.0"
   val AkkaBinaryVersion = "2.7"

project/Scala3.scala

@@ -0,0 +1,7 @@
+import sbt.Keys.crossScalaVersions
+
+object Scala3 {
+
+  val settings = Seq(crossScalaVersions := Dependencies.ScalaVersions)
+
+}