feat: Scala 3 support

Author: johanandren

.github/workflows/validate-and-test.yml

@@ -53,7 +53,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        SCALA_VERSION: [2.12, 2.13]
+        SCALA_VERSION: [2.12, 2.13, 3.1]
         JABBA_JDK: [1.8, 1.11]
     steps:
       - name: Checkout

akka-http-bench-jmh/src/main/scala/akka/BenchRunner.scala

@@ -25,7 +25,7 @@ object BenchRunner {
     val opts = new CommandLineOptions(args2: _*)
     val results = new Runner(opts).run()
 
-    val report = results.asScala.map { result: RunResult =>
+    val report = results.asScala.map { (result: RunResult) =>
       val bench = result.getParams.getBenchmark
       val params = result.getParams.getParamsKeys.asScala.map(key => s"$key=${result.getParams.getParam(key)}").mkString("_")
       val score = result.getAggregatedResult.getPrimaryResult.getScore.round

akka-http-caching/src/main/scala/akka/http/caching/scaladsl/LfuCacheSettings.scala

@@ -22,10 +22,10 @@ abstract class LfuCacheSettings private[http] () extends javadsl.LfuCacheSetting
   def timeToLive: Duration
   def timeToIdle: Duration
 
-  final def getMaxCapacity: Int = maxCapacity
-  final def getInitialCapacity: Int = initialCapacity
-  final def getTimeToLive: Duration = timeToLive
-  final def getTimeToIdle: Duration = timeToIdle
+  final def getMaxCapacity: Int = self.maxCapacity
+  final def getInitialCapacity: Int = self.initialCapacity
+  final def getTimeToLive: Duration = self.timeToLive
+  final def getTimeToIdle: Duration = self.timeToIdle
 
   override def withMaxCapacity(newMaxCapacity: Int): LfuCacheSettings = self.copy(maxCapacity = newMaxCapacity)
   override def withInitialCapacity(newInitialCapacity: Int): LfuCacheSettings = self.copy(initialCapacity = newInitialCapacity)

akka-http-caching/src/main/scala/akka/http/javadsl/server/directives/CachingDirectives.scala

@@ -17,7 +17,7 @@ object CachingDirectives {
 
   import akka.http.scaladsl.server.directives.{ CachingDirectives => D }
 
-  private implicit def routeResultCacheMapping[K] =
+  private implicit def routeResultCacheMapping[K]: JavaMapping[Cache[K, RouteResult], akka.http.caching.scaladsl.Cache[K, akka.http.scaladsl.server.RouteResult]] =
     CacheJavaMapping.cacheMapping[K, RouteResult, K, akka.http.scaladsl.server.RouteResult]
 
   /**

akka-http-caching/src/test/scala/akka/http/caching/ExpiringLfuCacheSpec.scala

@@ -48,12 +48,14 @@ class ExpiringLfuCacheSpec extends AnyWordSpec with Matchers with BeforeAndAfter
     "return Futures on uncached values during evaluation and replace these with the value afterwards" in {
       val cache = lfuCache[String]()
       val latch = new CountDownLatch(1)
-      val future1 = cache(1, (promise: Promise[String]) =>
+      val future1 = cache(1, { (promise: Promise[String]) =>
         Future {
           latch.await()
           promise.success("A")
         }
-      )
+        // (block autoformat)
+        () // provide Unit result automatically to hand-hold Scala 3 overload selection
+      })
       val future2 = cache.get(1, () => "")
 
       latch.countDown()
@@ -150,7 +152,7 @@ class ExpiringLfuCacheSpec extends AnyWordSpec with Matchers with BeforeAndAfter
         }
       }, 10.second)
 
-      views.transpose.foreach { ints: Seq[Int] =>
+      views.transpose.foreach { (ints: Seq[Int]) =>
         ints.filter(_ != 0).reduceLeft((a, b) => if (a == b) a else 0) should not be 0
       }
     }

akka-http-core/src/main/java/akka/http/javadsl/model/Query.java

@@ -7,6 +7,7 @@
 import akka.http.impl.model.JavaQuery;
 import akka.http.impl.model.UriJavaAccessor;
 import akka.http.scaladsl.model.*;
+import akka.http.javadsl.model.HttpCharset;
 import akka.japi.Pair;
 import akka.parboiled2.CharPredicate;
 import akka.parboiled2.ParserInput$;

akka-http-core/src/main/mima-filters/10.2.9.backwards.excludes/http2-signature-changes.excludes

@@ -0,0 +1,2 @@
+# Changes to internal signatures
+ProblemFilters.exclude[Problem]("akka.http.impl.engine.http2.*")

akka-http-core/src/main/mima-filters/10.4.0.backwards.excludes/scala-3.excludes

@@ -0,0 +1,2 @@
+# MiMa doesn't get that scala.Serializable is alias for java.io.Serializable
+ProblemFilters.exclude[MissingTypesProblem]("akka.http.scaladsl.model.ErrorInfo")

akka-http-core/src/main/mima-filters/10.4.0.backwards.excludes/stream-utils.excludes

@@ -0,0 +1,2 @@
+# internal, changed earlier, not sure why not picked up from 10.1.x excludes for Scala 2.12
+ProblemFilters.exclude[ReversedMissingMethodProblem]("akka.http.impl.util.StreamUtils#ScheduleSupport.akka$http$impl$util$StreamUtils$ScheduleSupport$$super$materializer")

akka-http-core/src/main/scala/akka/http/impl/engine/client/OutgoingConnectionBlueprint.scala

@@ -97,7 +97,7 @@ private[http] object OutgoingConnectionBlueprint {
       val terminationFanout = b.add(Broadcast[HttpResponse](2))
 
       val logger = b.add(Flow[ByteString].mapError { case t => log.debug(s"Outgoing request stream error {}", t); t }.named("errorLogger"))
-      val wrapTls = b.add(Flow[ByteString].map(SendBytes))
+      val wrapTls = b.add(Flow[ByteString].map(SendBytes(_)))
 
       val collectSessionBytes = b.add(Flow[SslTlsInbound].collect { case s: SessionBytes => s })