Build with Scala 2.13

.travis.yml

@@ -29,6 +29,8 @@ jobs:
       name: "Build code style check (fixed with `sbt scalafmtSbt`)"
     - env: CMD="++2.11.12 Test/compile"
       name: "Compile all tests (with Scala 2.11)"
+    - env: CMD="++2.13.0-M5 Test/compile"
+      name: "Compile all tests (with Scala 2.13)"
     - env: CMD="unidoc"
       name: "Create all API docs"
     - env: CMD="docs/Paradox/paradox"

build.sbt

@@ -72,7 +72,8 @@ lazy val alpakka = project
       (ScalaUnidoc / unidoc / fullClasspath).value
         .filterNot(_.data.getAbsolutePath.contains("protobuf-java-2.5.0.jar"))
     },
-    ScalaUnidoc / unidoc / unidocProjectFilter := inAnyProject -- inProjects(`doc-examples`)
+    ScalaUnidoc / unidoc / unidocProjectFilter := inAnyProject -- inProjects(`doc-examples`),
+    crossScalaVersions := List() // workaround for https://github.com/sbt/sbt/issues/3465
   )
 
 lazy val amqp = alpakkaProject("amqp", "amqp", Dependencies.Amqp)
@@ -93,7 +94,7 @@ lazy val cassandra = alpakkaProject("cassandra", "cassandra", Dependencies.Cassa
 lazy val couchbase =
   alpakkaProject("couchbase", "couchbase", Dependencies.Couchbase, parallelExecution in Test := false)
 
-lazy val csv = alpakkaProject("csv", "csv", Dependencies.Csv)
+lazy val csv = alpakkaProject("csv", "csv", Dependencies.Csv, crossScalaVersions -= Dependencies.Scala213)
 
 lazy val dynamodb = alpakkaProject("dynamodb", "aws.dynamodb", Dependencies.DynamoDB)
 
@@ -115,11 +116,25 @@ lazy val ftp = alpakkaProject(
   parallelExecution in Test := false,
   fork in Test := true,
   // To avoid potential blocking in machines with low entropy (default is `/dev/random`)
-  javaOptions in Test += "-Djava.security.egd=file:/dev/./urandom"
+  javaOptions in Test += "-Djava.security.egd=file:/dev/./urandom",
+  crossScalaVersions -= Dependencies.Scala213
 )
 
 lazy val geode =
-  alpakkaProject("geode", "geode", Dependencies.Geode, fork in Test := true, parallelExecution in Test := false)
+  alpakkaProject(
+    "geode",
+    "geode",
+    Dependencies.Geode,
+    fork in Test := true,
+    parallelExecution in Test := false,
+    unmanagedSourceDirectories in Compile ++= {
+      val sourceDir = (sourceDirectory in Compile).value
+      CrossVersion.partialVersion(scalaVersion.value) match {
+        case Some((2, n)) if n >= 12 => Seq(sourceDir / "scala-2.12+")
+        case _ => Seq.empty
+      }
+    },
+  )
 
 lazy val googleCloudPubSub = alpakkaProject(
   "google-cloud-pub-sub",
@@ -141,7 +156,8 @@ lazy val googleCloudPubSubGrpc = alpakkaProject(
   javaAgents += Dependencies.GooglePubSubGrpcAlpnAgent % "test",
   // for the ExampleApp in the tests
   connectInput in run := true,
-  Compile / compile / scalacOptions += "-P:silencer:pathFilters=src_managed"
+  Compile / compile / scalacOptions += "-P:silencer:pathFilters=src_managed",
+  crossScalaVersions -= Dependencies.Scala213
 ).enablePlugins(AkkaGrpcPlugin, JavaAgent)
 
 lazy val googleFcm = alpakkaProject(
@@ -155,7 +171,11 @@ lazy val hbase = alpakkaProject("hbase", "hbase", Dependencies.HBase, fork in Te
 
 lazy val hdfs = alpakkaProject("hdfs", "hdfs", Dependencies.Hdfs, parallelExecution in Test := false)
 
-lazy val ironmq = alpakkaProject("ironmq", "ironmq", Dependencies.IronMq, fork in Test := true)
+lazy val ironmq = alpakkaProject("ironmq",
+                                 "ironmq",
+                                 Dependencies.IronMq,
+                                 fork in Test := true,
+                                 crossScalaVersions -= Dependencies.Scala213)
 
 lazy val jms = alpakkaProject("jms", "jms", Dependencies.Jms, parallelExecution in Test := false)
 
@@ -169,7 +189,8 @@ lazy val kinesis = alpakkaProject("kinesis",
 
 lazy val kudu = alpakkaProject("kudu", "kudu", Dependencies.Kudu, fork in Test := false)
 
-lazy val mongodb = alpakkaProject("mongodb", "mongodb", Dependencies.MongoDb)
+lazy val mongodb =
+  alpakkaProject("mongodb", "mongodb", Dependencies.MongoDb, crossScalaVersions -= Dependencies.Scala213)
 
 lazy val mqtt = alpakkaProject("mqtt", "mqtt", Dependencies.Mqtt)
 
@@ -193,21 +214,27 @@ lazy val springWeb = alpakkaProject("spring-web", "spring.web", Dependencies.Spr
 
 lazy val simpleCodecs = alpakkaProject("simple-codecs", "simplecodecs")
 
-lazy val slick = alpakkaProject("slick", "slick", Dependencies.Slick)
+lazy val slick = alpakkaProject("slick", "slick", Dependencies.Slick, crossScalaVersions -= Dependencies.Scala213)
 
-lazy val sns = alpakkaProject("sns",
-                              "aws.sns",
-                              Dependencies.Sns,
-                              // For mockito https://github.com/akka/alpakka/issues/390
-                              parallelExecution in Test := false)
+lazy val sns = alpakkaProject(
+  "sns",
+  "aws.sns",
+  Dependencies.Sns,
+  // For mockito https://github.com/akka/alpakka/issues/390
+  parallelExecution in Test := false,
+  crossScalaVersions -= Dependencies.Scala213
+)
 
 lazy val solr = alpakkaProject("solr", "solr", Dependencies.Solr, parallelExecution in Test := false)
 
-lazy val sqs = alpakkaProject("sqs",
-                              "aws.sqs",
-                              Dependencies.Sqs,
-                              // For mockito https://github.com/akka/alpakka/issues/390
-                              parallelExecution in Test := false)
+lazy val sqs = alpakkaProject(
+  "sqs",
+  "aws.sqs",
+  Dependencies.Sqs,
+  // For mockito https://github.com/akka/alpakka/issues/390
+  parallelExecution in Test := false,
+  crossScalaVersions -= Dependencies.Scala213
+)
 
 lazy val sse = alpakkaProject("sse", "sse", Dependencies.Sse)
 
@@ -297,6 +324,7 @@ lazy val `doc-examples` = project
     name := s"akka-stream-alpakka-doc-examples",
     publish / skip := true,
     whitesourceIgnore := true,
+    crossScalaVersions -= Dependencies.Scala213,
     Dependencies.`Doc-examples`
   )
 

dynamodb/src/test/scala/akka/stream/alpakka/dynamodb/ItemSpec.scala

@@ -85,9 +85,9 @@ class ItemSpec extends TestKit(ActorSystem("ItemSpec")) with AsyncWordSpecLike w
     "9) get two items in a transaction" ignore assertAllStagesStopped {
       DynamoDb.single(transactGetItemsRequest).map { results =>
         results.getResponses.size shouldBe 2
-        val Seq(a, b) = results.getResponses.asScala
-        a.getItem.get(sortCol) shouldEqual N(0)
-        b.getItem.get(sortCol) shouldEqual N(1)
+        val responses = results.getResponses.asScala
+        responses.head.getItem.get(sortCol) shouldEqual N(0)
+        responses.last.getItem.get(sortCol) shouldEqual N(1)
       }
     }
 

geode/src/main/scala-2.11/akka/stream/alpakka/geode/GeodeSettings.scala

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2016-2018 Lightbend Inc. <http://www.lightbend.com>
+ * Copyright (C) 2016-2019 Lightbend Inc. <http://www.lightbend.com>
  */
 
 package akka.stream.alpakka.geode

hbase/src/main/scala/akka/stream/alpakka/hbase/HTableSettings.scala

@@ -30,7 +30,7 @@ final class HTableSettings[T] private (val conf: Configuration,
    * Java Api
    */
   def withColumnFamilies(columnFamilies: java.util.List[String]): HTableSettings[T] =
-    copy(columnFamilies = columnFamilies.asScala.to[immutable.Seq])
+    copy(columnFamilies = columnFamilies.asScala.toIndexedSeq)
 
   def withConverter(converter: T => immutable.Seq[Mutation]): HTableSettings[T] =
     copy(converter = converter)
@@ -39,7 +39,7 @@ final class HTableSettings[T] private (val conf: Configuration,
    * Java Api
    */
   def withConverter(converter: java.util.function.Function[T, java.util.List[Mutation]]): HTableSettings[T] =
-    copy(converter = converter.asScala(_).asScala.to[immutable.Seq])
+    copy(converter = converter.asScala(_).asScala.toIndexedSeq)
 
   override def toString: String =
     "HTableSettings(" +
@@ -76,8 +76,5 @@ object HTableSettings {
                 tableName: TableName,
                 columnFamilies: java.util.List[String],
                 converter: java.util.function.Function[T, java.util.List[Mutation]]): HTableSettings[T] =
-    HTableSettings(conf,
-                   tableName,
-                   columnFamilies.asScala.to[immutable.Seq],
-                   converter.asScala(_).asScala.to[immutable.Seq])
+    HTableSettings(conf, tableName, columnFamilies.asScala.toIndexedSeq, converter.asScala(_).asScala.toIndexedSeq)
 }

hdfs/src/test/scala/akka/stream/alpakka/hdfs/util/TestUtils.scala

@@ -196,10 +196,10 @@ object JavaTestUtils extends TestUtils {
     assertEquals(getFiles(fs).size(), logs.size())
 
   def readLogs(fs: FileSystem, logs: Sequence[RotationMessage]): Sequence[String] =
-    ScalaTestUtils.readLogs(fs, logs.asScala).asJava
+    ScalaTestUtils.readLogs(fs, logs.asScala.toIndexedSeq).asJava
 
   def readLogsWithFlatten(fs: FileSystem, logs: Sequence[RotationMessage]): Sequence[Char] =
-    ScalaTestUtils.readLogsWithFlatten(fs, logs.asScala).asJava
+    ScalaTestUtils.readLogsWithFlatten(fs, logs.asScala.toIndexedSeq).asJava
 
   def generateFakeContentWithPartitions(count: Double, bytes: Long, partition: Int): Sequence[ByteString] =
     ScalaTestUtils.generateFakeContentWithPartitions(count, bytes, partition).asJava
@@ -209,8 +209,9 @@ object JavaTestUtils extends TestUtils {
                           logs: Sequence[RotationMessage],
                           codec: CompressionCodec): Assertion = {
     val pureContent: String = content.asScala.map(_.utf8String).mkString
-    val contentFromHdfsWithCodec: String = ScalaTestUtils.readLogsWithCodec(fs, logs.asScala, codec).mkString
-    val contentFromHdfs: String = ScalaTestUtils.readLogs(fs, logs.asScala).mkString
+    val contentFromHdfsWithCodec: String =
+      ScalaTestUtils.readLogsWithCodec(fs, logs.asScala.toIndexedSeq, codec).mkString
+    val contentFromHdfs: String = ScalaTestUtils.readLogs(fs, logs.asScala.toIndexedSeq).mkString
     assertNotEquals(contentFromHdfs, pureContent)
     assertEquals(contentFromHdfsWithCodec, pureContent)
   }
@@ -225,7 +226,7 @@ object JavaTestUtils extends TestUtils {
     ScalaTestUtils.generateFakeContentForSequence(count, bytes).map { case (k, v) => akka.japi.Pair(k, v) }.asJava
 
   def readLogsWithCodec(fs: FileSystem, logs: Sequence[RotationMessage], codec: CompressionCodec): Sequence[String] =
-    ScalaTestUtils.readLogsWithCodec(fs, logs.asScala, codec).asJava
+    ScalaTestUtils.readLogsWithCodec(fs, logs.asScala.toIndexedSeq, codec).asJava
 
   def verifyFlattenContent(fs: FileSystem, logs: Sequence[RotationMessage], content: Sequence[ByteString]): Unit =
     assertArrayEquals(readLogsWithFlatten(fs, logs).toArray, content.asScala.flatMap(_.utf8String).asJava.toArray)

jms/src/main/scala/akka/stream/alpakka/jms/impl/SoftReferenceCache.scala

@@ -36,5 +36,5 @@ private final class SoftReferenceCache[K, V <: AnyRef] {
   }
 
   private def purgeCache(): Unit =
-    cache --= cache.collect { case (key, ref) if ref.get.isEmpty => key }.to[Vector]
+    cache --= cache.collect { case (key, ref) if ref.get.isEmpty => key }.toVector
 }

jms/src/test/scala/akka/stream/alpakka/jms/scaladsl/JmsAckConnectorsSpec.scala

@@ -14,7 +14,7 @@ import javax.jms.{JMSException, TextMessage}
 import org.scalatest.Inspectors._
 
 import scala.annotation.tailrec
-import scala.collection.{mutable, SortedSet}
+import scala.collection.mutable
 import scala.concurrent.Future
 import scala.concurrent.duration._
 import scala.util.{Failure, Success}
@@ -280,7 +280,7 @@ class JmsAckConnectorsSpec extends JmsSpec {
 
       killSwitch2.shutdown()
 
-      resultList.to[SortedSet] should contain theSameElementsAs numsIn.map(_.toString)
+      resultList.toSet should contain theSameElementsAs numsIn.map(_.toString)
     }
 
     "ensure no message loss when aborting a stream" in withServer() { server =>
@@ -360,7 +360,7 @@ class JmsAckConnectorsSpec extends JmsSpec {
       implicit val _ = Ordering.by { s: String =>
         s.toInt
       }
-      resultList.to[SortedSet] should contain theSameElementsAs numsIn.map(_.toString)
+      resultList.toSet should contain theSameElementsAs numsIn.map(_.toString)
     }
 
     "shutdown when waiting to acknowledge messages" in withServer() { server =>

jms/src/test/scala/docs/scaladsl/JmsBufferedAckConnectorsSpec.scala

@@ -16,7 +16,7 @@ import javax.jms.{JMSException, TextMessage}
 import org.scalatest.Inspectors._
 
 import scala.annotation.tailrec
-import scala.collection.{immutable, mutable, SortedSet}
+import scala.collection.{immutable, mutable}
 import scala.concurrent.Future
 import scala.concurrent.duration._
 import scala.util.{Failure, Success}
@@ -287,7 +287,7 @@ class JmsBufferedAckConnectorsSpec extends JmsSpec {
       implicit val _ = Ordering.by { s: String =>
         s.toInt
       }
-      resultList.to[SortedSet] should contain theSameElementsAs numsIn.map(_.toString)
+      resultList.toSet should contain theSameElementsAs numsIn.map(_.toString)
     }
 
     "ensure no message loss when aborting a stream" in withConnectionFactory() { connectionFactory =>
@@ -372,7 +372,7 @@ class JmsBufferedAckConnectorsSpec extends JmsSpec {
       implicit val _ = Ordering.by { s: String =>
         s.toInt
       }
-      resultList.to[SortedSet] should contain theSameElementsAs numsIn.map(_.toString)
+      resultList.toSet should contain theSameElementsAs numsIn.map(_.toString)
     }
   }
 }

kinesis/src/main/scala/akka/stream/alpakka/kinesisfirehose/impl/KinesisFirehoseFlowStage.scala

@@ -177,6 +177,7 @@ private[kinesisfirehose] object KinesisFirehoseFlowStage {
                 result.getRequestResponses.asScala
                   .zip(request.getRecords.asScala)
                   .filter(_._1.getErrorCode != null)
+                  .toIndexedSeq
               )
             } else {
               retryRecordsCallback(Nil)

kinesis/src/main/scala/akka/stream/alpakka/kinesisfirehose/scaladsl/KinesisFirehoseFlow.scala

@@ -13,7 +13,7 @@ import com.amazonaws.services.kinesisfirehose.AmazonKinesisFirehoseAsync
 import com.amazonaws.services.kinesisfirehose.model.{PutRecordBatchResponseEntry, Record}
 
 import scala.collection.JavaConverters._
-import scala.collection.immutable.{Iterable, Queue}
+import scala.collection.immutable.Queue
 import scala.concurrent.duration._
 
 object KinesisFirehoseFlow {
@@ -33,7 +33,7 @@ object KinesisFirehoseFlow {
         )
       )
       .mapAsync(settings.parallelism)(identity)
-      .mapConcat(_.getRequestResponses.asScala.to[Iterable])
+      .mapConcat(_.getRequestResponses.asScala.toIndexedSeq)
       .filter(_.getErrorCode == null)
 
   private def getByteSize(record: Record): Int = record.getData.position

mqtt-streaming/src/main/scala/akka/stream/alpakka/mqtt/streaming/model.scala

@@ -365,7 +365,7 @@ final case class Subscribe @InternalApi private[streaming] (packetId: PacketId,
    * http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html
    */
   def this(topicFilters: java.util.List[AkkaPair[String, Integer]]) =
-    this(PacketId(0), topicFilters.asScala.map(v => v.first -> ControlPacketFlags(v.second)))
+    this(PacketId(0), topicFilters.asScala.toIndexedSeq.map(v => v.first -> ControlPacketFlags(v.second)))
 
   /**
    * A convenience for subscribing to a single topic with at-least-once semantics
@@ -388,7 +388,7 @@ final case class SubAck(packetId: PacketId, returnCodes: Seq[ControlPacketFlags]
    * http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html
    */
   def this(packetId: PacketId, returnCodes: java.util.List[Integer]) =
-    this(packetId, returnCodes.asScala.map(v => ControlPacketFlags(v)))
+    this(packetId, returnCodes.asScala.toIndexedSeq.map(v => ControlPacketFlags(v)))
 }
 
 object Unsubscribe {
@@ -428,7 +428,7 @@ final case class Unsubscribe @InternalApi private[streaming] (packetId: PacketId
    * http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html
    */
   def this(topicFilters: java.util.List[String]) =
-    this(PacketId(0), topicFilters.asScala)
+    this(PacketId(0), topicFilters.asScala.toIndexedSeq)
 
   /**
    * A convenience for unsubscribing from a single topic

project/Common.scala

@@ -28,7 +28,7 @@ object Common extends AutoPlugin {
     whitesourceGroup := Whitesource.Group.Community,
     crossVersion := CrossVersion.binary,
     crossScalaVersions := Dependencies.ScalaVersions,
-    scalaVersion := crossScalaVersions.value.head,
+    scalaVersion := Dependencies.Scala212,
     scalacOptions ++= Seq(
       "-encoding",
       "UTF-8",
@@ -37,11 +37,14 @@ object Common extends AutoPlugin {
       "-deprecation",
       //"-Xfatal-warnings",
       "-Xlint",
-      "-Yno-adapted-args",
       "-Ywarn-dead-code",
       "-Xfuture",
       "-target:jvm-1.8"
     ),
+    scalacOptions ++= (scalaVersion.value match {
+      case Dependencies.Scala213 => Seq.empty[String]
+      case _ => Seq("-Yno-adapted-args")
+    }),
     Compile / doc / scalacOptions := scalacOptions.value ++ Seq(
       "-doc-title",
       "Alpakka",