support cross-building for scala 3

.github/workflows/pr.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       matrix:
         java: [21]
-        scala: [2.13.13]
+        scala: [2.13.13, 3.4.1]
     steps:
       - uses: actions/checkout@v3
       - name: Set up JDK ${{ matrix.java }}

atlas-aggregator/src/main/scala/com/netflix/atlas/aggregator/PayloadDecoder.scala

@@ -25,12 +25,10 @@ import com.netflix.atlas.core.validation.CompositeTagRule
 import com.netflix.atlas.core.validation.Rule
 import com.netflix.atlas.core.validation.TagRule
 import com.netflix.atlas.core.validation.ValidationResult
-import com.netflix.iep.config.NetflixEnvironment
 import com.netflix.iep.config.ConfigListener
 import com.netflix.iep.config.ConfigManager
 import com.netflix.spectator.api.Id
 import com.netflix.spectator.api.NoopRegistry
-import com.netflix.spectator.api.Tag
 import com.netflix.spectator.atlas.impl.Parser
 import com.netflix.spectator.atlas.impl.Query
 import com.netflix.spectator.atlas.impl.QueryIndex

atlas-cloudwatch/src/main/scala/com/netflix/atlas/cloudwatch/CloudWatchMetricsProcessor.scala

@@ -538,7 +538,6 @@ abstract class CloudWatchMetricsProcessor(
                       publishRouter.publish(atlasDp)
                     }
                   }
-                case (_, _) => // no-op
               }
             }
         }

atlas-cloudwatch/src/main/scala/com/netflix/atlas/cloudwatch/RedisClusterCloudWatchMetricsProcessor.scala

@@ -272,20 +272,23 @@ class RedisClusterCloudWatchMetricsProcessor(
           Using.resource(jedis.getClusterNodes.get(node).getResource) { jedis =>
             try {
               var cursor: Array[Byte] = ScanParams.SCAN_POINTER_START_BINARY
-              do {
+              while ({
+                // do
                 val scanResult = jedis.executeCommand(commandObjects.scan(cursor, scanParams))
                 val keys = scanResult.getResult.asScala.toSeq
                 logger.debug(s"Scanned keys ${keys.size} from node ${node}")
                 if (keys.nonEmpty) {
-                  keys.foreach(k => {
+                  keys.foreach { k =>
                     val slot = JedisClusterCRC16.getSlot(k)
                     val slotKeys = slotToKeys.getOrElseUpdate(slot, new ArrayBuffer[Array[Byte]]())
                     slotKeys += k
-                  })
+                  }
                   sum += keys.size
                 }
                 cursor = scanResult.getCursorAsBytes
-              } while (!util.Arrays.equals(cursor, ScanParams.SCAN_POINTER_START_BINARY))
+                // while
+                !util.Arrays.equals(cursor, ScanParams.SCAN_POINTER_START_BINARY)
+              }) ()
               true
             } catch {
               case ex: Exception =>

iep-lwc-fwding-admin/src/main/scala/com/netflix/iep/lwc/fwd/admin/MarkerService.scala

@@ -46,7 +46,7 @@ import scala.concurrent.Future
 import scala.concurrent.duration.*
 
 trait MarkerService {
-  var queue: SourceQueue[Report]
+  def queue: SourceQueue[Report]
 }
 
 class MarkerServiceImpl(
@@ -66,7 +66,9 @@ class MarkerServiceImpl(
   private implicit val ec: ExecutionContext = scala.concurrent.ExecutionContext.global
   private var killSwitch: KillSwitch = _
 
-  override var queue: SourceQueue[Report] = _
+  private var sourceQueue: SourceQueue[Report] = _
+
+  override def queue: SourceQueue[Report] = sourceQueue
 
   override def startImpl(): Unit = {
     val sizeLimit = config.getInt("iep.lwc.fwding-admin.queue-size-limit")
@@ -94,7 +96,7 @@ class MarkerServiceImpl(
       .toMat(Sink.ignore)(Keep.left)
       .run()
 
-    queue = q
+    sourceQueue = q
     killSwitch = k
 
     logger.info("MarkerService started")
@@ -113,7 +115,7 @@ object MarkerServiceImpl extends StrictLogging {
     scalingPolicies: ActorSelection
   )(implicit ec: ExecutionContext): Flow[Report, ScalingPolicyStatus, NotUsed] = {
     import ScalingPolicies.*
-    implicit val askTimeout = Timeout(15.seconds)
+    implicit val askTimeout: Timeout = Timeout(15.seconds)
 
     Flow[Report]
       .mapAsync(1) { r =>

iep-lwc-fwding-admin/src/test/scala/com/netflix/iep/lwc/fwd/admin/ApiSuite.scala

@@ -164,7 +164,7 @@ class MarkerServiceTest(implicit
 
   var result = List.newBuilder[Report]
 
-  override var queue: SourceQueue[Report] = StreamOps
+  override val queue: SourceQueue[Report] = StreamOps
     .blockingQueue[Report](new NoopRegistry(), "fwdingAdminCwReports", 1)
     .map(result += _)
     .toMat(Sink.ignore)(Keep.left)

project/BuildSettings.scala

@@ -6,10 +6,8 @@ object BuildSettings {
   val compilerFlags = Seq(
     "-deprecation",
     "-unchecked",
-    "-Xlint:_,-infer-any",
     "-feature",
     "-release", "21",
-    "-Xsource:3"
   )
 
   lazy val checkLicenseHeaders = taskKey[Unit]("Check the license headers for all source files.")
@@ -20,7 +18,12 @@ object BuildSettings {
   lazy val buildSettings = baseSettings ++ Seq(
     organization := "com.netflix.iep-apps",
     scalaVersion := Dependencies.Versions.scala,
-    scalacOptions ++= compilerFlags,
+    scalacOptions := {
+      CrossVersion.partialVersion(scalaVersion.value) match {
+        case Some((2, _)) => compilerFlags ++ Seq("-Xlint:_,-infer-any", "-Xsource:3")
+        case _            => compilerFlags ++ Seq("-source", "3.3")
+      }
+    },
     javacOptions ++= Seq("--release", "21"),
     crossPaths := true,
     crossScalaVersions := Dependencies.Versions.crossScala,

project/Dependencies.scala

@@ -17,7 +17,7 @@ object Dependencies {
     val spring     = "6.0.7"
     val avroV      = "1.11.3"
 
-    val crossScala = Seq(scala)
+    val crossScala = Seq(scala, "3.4.1")
   }
 
   import Versions._
@@ -59,7 +59,7 @@ object Dependencies {
   val log4jJul           = "org.apache.logging.log4j" % "log4j-jul" % log4j
   val log4jSlf4j         = "org.apache.logging.log4j" % "log4j-slf4j-impl" % log4j
   val mockitoCore        = "org.mockito" % "mockito-core" % "5.10.0"
-  val mockitoScala       = "org.mockito" % "mockito-scala_2.13" % "1.17.30"
+  val mockitoScala       = "org.mockito" %% "mockito-scala" % "1.17.30" // https://github.com/mockito/mockito-scala/issues/364
   val munit              = "org.scalameta" %% "munit" % "0.7.29"
   val openHFT            = "net.openhft" % "zero-allocation-hashing" % "0.16"
   val pekkoActor         = "org.apache.pekko" %% "pekko-actor" % pekko