Port Navigator to Scala 2.13 (#8847)

changelog_begin
changelog_end

ci/build.yml

@@ -184,6 +184,7 @@ jobs:
           //ledger-service/... \
           //triggers/... \
           //daml-script/... \
+          //navigator/... \
           -//ledger/ledger-api-test-tool/... \
           -//ledger/ledger-api-test-tool-on-canton/...
           # gatling-utils tests fail with a ClassNotFoundException for scala.collection.SeqLike
@@ -196,6 +197,7 @@ jobs:
           //ledger-service/... \
           //daml-script/... \
           //triggers/... \
+          //navigator/... \
           -//libs-scala/gatling-utils/... \
           -//ledger/ledger-api-test-tool/... \
           -//ledger/ledger-api-test-tool-on-canton/...

navigator/backend/BUILD.bazel

@@ -37,12 +37,37 @@ da_scala_library(
     srcs = glob([
         "src/main/scala/**/*.scala",
     ]),
+    scala_deps = [
+        "@maven//:com_chuusai_shapeless",
+        "@maven//:com_github_pureconfig_pureconfig_core",
+        "@maven//:com_github_pureconfig_pureconfig_generic",
+        "@maven//:com_github_scopt_scopt",
+        "@maven//:com_lihaoyi_sourcecode",
+        "@maven//:com_typesafe_akka_akka_actor",
+        "@maven//:com_typesafe_akka_akka_http",
+        "@maven//:com_typesafe_akka_akka_http_core",
+        "@maven//:com_typesafe_akka_akka_http_spray_json",
+        "@maven//:com_typesafe_akka_akka_stream",
+        "@maven//:com_typesafe_scala_logging_scala_logging",
+        "@maven//:io_spray_spray_json",
+        "@maven//:org_sangria_graphql_sangria",
+        "@maven//:org_sangria_graphql_sangria_marshalling_api",
+        "@maven//:org_scalaz_scalaz_core",
+        "@maven//:org_tpolecat_doobie_core",
+        "@maven//:org_tpolecat_doobie_free",
+        "@maven//:org_typelevel_cats_core",
+        "@maven//:org_typelevel_cats_effect",
+        "@maven//:org_typelevel_cats_free",
+        "@maven//:org_typelevel_cats_kernel",
+    ],
+    scala_runtime_deps = [
+        "@maven//:com_typesafe_akka_akka_slf4j",
+    ],
     scalacopts = navigator_scalacopts,
     silent_annotations = True,
     visibility = ["//visibility:public"],
     runtime_deps = [
         "@maven//:ch_qos_logback_logback_classic",
-        "@maven//:com_typesafe_akka_akka_slf4j_2_12",
         "@maven//:org_xerial_sqlite_jdbc",
     ],
     deps = [
@@ -63,31 +88,10 @@ da_scala_library(
         "//libs-scala/build-info",
         "//libs-scala/grpc-utils",
         "//libs-scala/scala-utils",
-        "@maven//:com_chuusai_shapeless_2_12",
-        "@maven//:com_github_pureconfig_pureconfig_core_2_12",
-        "@maven//:com_github_pureconfig_pureconfig_generic_2_12",
-        "@maven//:com_github_scopt_scopt_2_12",
-        "@maven//:com_lihaoyi_sourcecode_2_12",
-        "@maven//:com_typesafe_akka_akka_actor_2_12",
-        "@maven//:com_typesafe_akka_akka_http_2_12",
-        "@maven//:com_typesafe_akka_akka_http_core_2_12",
-        "@maven//:com_typesafe_akka_akka_http_spray_json_2_12",
-        "@maven//:com_typesafe_akka_akka_stream_2_12",
         "@maven//:com_typesafe_config",
-        "@maven//:com_typesafe_scala_logging_scala_logging_2_12",
         "@maven//:io_grpc_grpc_netty",
         "@maven//:io_netty_netty_handler",
-        "@maven//:io_spray_spray_json_2_12",
-        "@maven//:org_sangria_graphql_sangria_2_12",
-        "@maven//:org_sangria_graphql_sangria_marshalling_api_2_12",
-        "@maven//:org_scalaz_scalaz_core_2_12",
         "@maven//:org_slf4j_slf4j_api",
-        "@maven//:org_tpolecat_doobie_core_2_12",
-        "@maven//:org_tpolecat_doobie_free_2_12",
-        "@maven//:org_typelevel_cats_core_2_12",
-        "@maven//:org_typelevel_cats_effect_2_12",
-        "@maven//:org_typelevel_cats_free_2_12",
-        "@maven//:org_typelevel_cats_kernel_2_12",
     ],
 )
 
@@ -100,10 +104,15 @@ da_scala_library(
             "src/test/**/*Test.scala",
         ],
     ),
+    scala_deps = [
+        "@maven//:org_scalaz_scalaz_core",
+    ],
+    scala_runtime_deps = [
+        "@maven//:com_typesafe_akka_akka_stream_testkit",
+    ],
     scalacopts = navigator_scalacopts,
     runtime_deps = [
         "@maven//:ch_qos_logback_logback_classic",
-        "@maven//:com_typesafe_akka_akka_stream_testkit_2_12",
         "@maven//:io_grpc_grpc_netty",
         "@maven//:org_xerial_sqlite_jdbc",
     ],
@@ -115,7 +124,6 @@ da_scala_library(
         "//language-support/scala/bindings",
         "//ledger-service/lf-value-json",
         "//ledger/ledger-api-common",
-        "@maven//:org_scalaz_scalaz_core_2_12",
     ],
 )
 
@@ -150,6 +158,22 @@ da_scala_test_suite(
         "src/test/**/*Test.scala",
     ]),
     data = ["//ledger/test-common:dar-files"],
+    scala_deps = [
+        "@maven//:com_typesafe_akka_akka_actor",
+        "@maven//:com_typesafe_akka_akka_http",
+        "@maven//:com_typesafe_akka_akka_http_core",
+        "@maven//:com_typesafe_akka_akka_http_spray_json",
+        "@maven//:com_typesafe_akka_akka_http_testkit",
+        "@maven//:com_typesafe_akka_akka_stream",
+        "@maven//:com_typesafe_scala_logging_scala_logging",
+        "@maven//:io_spray_spray_json",
+        "@maven//:org_sangria_graphql_sangria",
+        "@maven//:org_sangria_graphql_sangria_marshalling_api",
+        "@maven//:org_scalacheck_scalacheck",
+        "@maven//:org_scalatest_scalatest",
+        "@maven//:org_scalatestplus_scalacheck_1_14",
+        "@maven//:org_scalaz_scalaz_core",
+    ],
     scalacopts = navigator_scalacopts,
     deps = [
         ":navigator-library",
@@ -175,21 +199,7 @@ da_scala_test_suite(
         "//libs-scala/ports",
         "//libs-scala/resources",
         "//libs-scala/timer-utils",
-        "@maven//:com_typesafe_akka_akka_actor_2_12",
-        "@maven//:com_typesafe_akka_akka_http_2_12",
-        "@maven//:com_typesafe_akka_akka_http_core_2_12",
-        "@maven//:com_typesafe_akka_akka_http_spray_json_2_12",
-        "@maven//:com_typesafe_akka_akka_http_testkit_2_12",
-        "@maven//:com_typesafe_akka_akka_stream_2_12",
         "@maven//:com_typesafe_config",
-        "@maven//:com_typesafe_scala_logging_scala_logging_2_12",
-        "@maven//:io_spray_spray_json_2_12",
-        "@maven//:org_sangria_graphql_sangria_2_12",
-        "@maven//:org_sangria_graphql_sangria_marshalling_api_2_12",
-        "@maven//:org_scalacheck_scalacheck_2_12",
-        "@maven//:org_scalatest_scalatest_2_12",
-        "@maven//:org_scalatestplus_scalacheck_1_14_2_12",
-        "@maven//:org_scalaz_scalaz_core_2_12",
     ],
 )
 

navigator/backend/src/main/scala/com/digitalasset/navigator/UIBackend.scala

@@ -305,7 +305,7 @@ abstract class UIBackend extends LazyLogging with ApplicationInfoJsonSupport {
       sys.addShutdownHook {
         // Stop the web server, then the Akka system consuming the ledger API
         stopServer()
-        partyRefresh.foreach(_.cancel)
+        partyRefresh.foreach(_.cancel())
         stopAkka()
         ()
       }

navigator/backend/src/main/scala/com/digitalasset/navigator/config/Config.scala

@@ -27,7 +27,7 @@ final case class Config(users: Map[String, UserConfig] = Map.empty[String, UserC
 
   def userIds: Set[String] = users.keySet
 
-  def roles: Set[String] = users.values.flatMap(_.role.toList)(collection.breakOut)
+  def roles: Set[String] = users.values.view.flatMap(_.role.toList).toSet
 }
 
 sealed abstract class ConfigReadError extends Product with Serializable {

navigator/backend/src/main/scala/com/digitalasset/navigator/data/DatabaseActions.scala

@@ -64,7 +64,7 @@ class DatabaseActions extends LazyLogging {
     Queries.createCommandTable.update.run *>
     Queries.commandIdIndex.update.run)
     .transact(xa)
-    .unsafeRunSync
+    .unsafeRunSync()
 
   def schema(): Try[String] = {
     Try(

navigator/backend/src/main/scala/com/digitalasset/navigator/dotnot/package.scala

@@ -114,7 +114,7 @@ package dotnot {
       * @param delegate the dotnot handler for `e`
       */
     def onElements[E](getName: E => String, delegate: OnTreeReady[E, R, C])(implicit
-        ev: T <:< Traversable[E]
+        ev: T <:< Iterable[E]
     ): OnTreeReady[T, R, C] = {
       val action: (T, PropertyCursor, String, C) => Either[DotNotFailure, R] =
         (t: T, cursor: PropertyCursor, value: String, context: C) => {
@@ -222,7 +222,7 @@ package dotnot {
     def perform[K](f: (T, K) => R)(implicit readK: Read[K]): OnLeafReady[T, R, C] = {
       val action: Action[T, R, C] = (t: T, cursor: PropertyCursor, value: String, _: C) => {
         if (cursor.isLast) {
-          Right(f(t, readK.from(value).right.get))
+          Right(f(t, readK.from(value).toOption.get))
         } else {
           Left(MustBeLastPart(onLeaf.onTreeOld.target, cursor, value))
         }

navigator/backend/src/main/scala/com/digitalasset/navigator/graphql/GraphQLSchema.scala

@@ -40,10 +40,27 @@ case class UserFacingError(message: String)
   override def getMessage: String = message
 }
 
+private object Implicits {
+
+  implicit final class `ExtendedInterfaceType Ops`[Ctx, Val](
+      private val self: InterfaceType[Ctx, Val]
+  ) extends AnyVal {
+    // Hack around https://github.com/scala/bug/issues/11662 which
+    // otherwise results in the implicit PossibleObject constructor
+    // being ambiguous due to the also implicit apply method.
+    def withPossibleObjectTypes(possible: () => List[ObjectType[Ctx, _]]) =
+      self.withPossibleTypes(() => possible().map(new PossibleObject[Ctx, Val](_)))
+  }
+}
+
 /** Schema definition for the UI backend GraphQL API. */
-@SuppressWarnings(Array("org.wartremover.warts.JavaSerializable"))
+@SuppressWarnings(
+  Array("org.wartremover.warts.JavaSerializable", "org.wartremover.warts.Serializable")
+)
 final class GraphQLSchema(customEndpoints: Set[CustomEndpoint[_]]) {
 
+  import Implicits._
+
   implicit private val actorTimeout: Timeout = Timeout(60, TimeUnit.SECONDS)
   implicit private val executionContext: ExecutionContext = ExecutionContext.global
 
@@ -105,12 +122,12 @@ final class GraphQLSchema(customEndpoints: Set[CustomEndpoint[_]]) {
   )
 
   //noinspection ForwardReference
-  val NodeType: InterfaceType[GraphQLContext, Node[_]] = InterfaceType(
+  val NodeType: InterfaceType[GraphQLContext, Node[_]] = InterfaceType[GraphQLContext, Node[_]](
     "Node",
     fields[GraphQLContext, Node[_]](
       Field("id", IDType, resolve = _.value.idString)
     ),
-  ).withPossibleTypes(() =>
+  ).withPossibleObjectTypes(() =>
     List(
       TransactionType,
       TemplateType,
@@ -132,7 +149,7 @@ final class GraphQLSchema(customEndpoints: Set[CustomEndpoint[_]]) {
       Field("module", StringType, resolve = _.value.id.qualifiedName.module.toString()),
       Field("name", StringType, resolve = _.value.id.qualifiedName.name.toString()),
     ),
-  ).withPossibleTypes(() =>
+  ).withPossibleObjectTypes(() =>
     List(
       DamlLfDefDataTypeType,
       TemplateType,
@@ -231,7 +248,7 @@ final class GraphQLSchema(customEndpoints: Set[CustomEndpoint[_]]) {
           resolve = context => Tag.unwrap[String, ApiTypes.WorkflowIdTag](context.value.workflowId),
         ),
       ),
-  ).withPossibleTypes(() => List(CreatedEventType, ExercisedEventType))
+  ).withPossibleObjectTypes(() => List(CreatedEventType, ExercisedEventType))
 
   //noinspection ForwardReference
   val CreatedEventType: ObjectType[GraphQLContext, ContractCreated] = ObjectType(
@@ -294,7 +311,7 @@ final class GraphQLSchema(customEndpoints: Set[CustomEndpoint[_]]) {
       ),
   )
 
-  val TransactionType = ObjectType(
+  val TransactionType: ObjectType[GraphQLContext, Transaction] = ObjectType(
     "Transaction",
     interfaces[GraphQLContext, Transaction](NodeType),
     () =>
@@ -382,7 +399,7 @@ final class GraphQLSchema(customEndpoints: Set[CustomEndpoint[_]]) {
       fields[GraphQLContext, CommandStatus](
         Field("completed", BooleanType, resolve = _.value.isCompleted)
       ),
-  ).withPossibleTypes(() =>
+  ).withPossibleObjectTypes(() =>
     List(
       CommandStatusErrorType,
       CommandStatusWaitingType,
@@ -448,7 +465,7 @@ final class GraphQLSchema(customEndpoints: Set[CustomEndpoint[_]]) {
               .getOrElse(CommandStatusUnknown()),
         ),
       ),
-  ).withPossibleTypes(() => List(CreateCommandType, ExerciseCommandType))
+  ).withPossibleObjectTypes(() => List(CreateCommandType, ExerciseCommandType))
 
   val CreateCommandType: ObjectType[GraphQLContext, CreateCommand] = ObjectType(
     "CreateCommand",
@@ -844,12 +861,14 @@ final class GraphQLSchema(customEndpoints: Set[CustomEndpoint[_]]) {
 
   def filterCriteria(arg: Seq[DefaultInput]): AndFilterCriterion =
     AndFilterCriterion(
-      arg.map(input =>
+      arg.view
-        FilterCriterion(
+        .map(input =>
-          input("field").toString,
+          FilterCriterion(
-          input("value").toString,
+            input("field").toString,
+            input("value").toString,
+          )
         )
-      )(collection.breakOut)
+        .toList
     )
 
   private def parseInstant(s: String): Either[Violation, Instant] = Try(Instant.parse(s)) match {

navigator/backend/src/main/scala/com/digitalasset/navigator/graphql/JsonType.scala

@@ -69,22 +69,22 @@ object JsonType {
     ScalarType[JsValue](
       name,
       description = description,
-      coerceOutput = (value, _) ⇒ value,
+      coerceOutput = (value, _) => value,
       coerceUserInput = {
-        case v: String ⇒ Right(JsString(v))
+        case v: String => Right(JsString(v): JsValue)
-        case v: Boolean ⇒ Right(JsBoolean(v))
+        case v: Boolean => Right(JsBoolean(v))
-        case v: Int ⇒ Right(JsNumber(v))
+        case v: Int => Right(JsNumber(v))
-        case v: Long ⇒ Right(JsNumber(v))
+        case v: Long => Right(JsNumber(v))
-        case v: Float ⇒ Right(JsNumber(v.toDouble))
+        case v: Float => Right(JsNumber(v.toDouble): JsValue)
-        case v: Double ⇒ Right(JsNumber(v))
+        case v: Double => Right(JsNumber(v): JsValue)
-        case v: BigInt ⇒ Right(JsNumber(v))
+        case v: BigInt => Right(JsNumber(v))
-        case v: BigDecimal ⇒ Right(JsNumber(v))
+        case v: BigDecimal => Right(JsNumber(v))
-        case v: JsValue ⇒ Right(v)
+        case v: JsValue => Right(v)
       },
       coerceInput = {
-        case ast.StringValue(jsonStr, _, _, _, _) ⇒
+        case ast.StringValue(jsonStr, _, _, _, _) =>
           Right(jsonStr.parseJson)
-        case _ ⇒
+        case _ =>
           Left(JsonCoercionViolation)
       },
     )

navigator/backend/src/main/scala/com/digitalasset/navigator/graphql/SprayMarshallers.scala

@@ -36,22 +36,22 @@ object SprayMarshallers {
 
     def arrayNode(values: Vector[JsValue]) = JsArray(values)
     def optionalArrayNodeValue(value: Option[JsValue]): JsValue = value match {
-      case Some(v) ⇒ v
+      case Some(v) => v
-      case None ⇒ nullNode
+      case None => nullNode
     }
 
     def scalarNode(value: Any, typeName: String, info: Set[ScalarValueInfo]): JsValue =
       value match {
-        case v: String ⇒ JsString(v)
+        case v: String => JsString(v)
-        case v: Boolean ⇒ JsBoolean(v)
+        case v: Boolean => JsBoolean(v)
-        case v: Int ⇒ JsNumber(v)
+        case v: Int => JsNumber(v)
-        case v: Long ⇒ JsNumber(v)
+        case v: Long => JsNumber(v)
-        case v: Float ⇒ JsNumber(v.toDouble)
+        case v: Float => JsNumber(v.toDouble)
-        case v: Double ⇒ JsNumber(v)
+        case v: Double => JsNumber(v)
-        case v: BigInt ⇒ JsNumber(v)
+        case v: BigInt => JsNumber(v)
-        case v: BigDecimal ⇒ JsNumber(v)
+        case v: BigDecimal => JsNumber(v)
-        case v: JsValue ⇒ v
+        case v: JsValue => v
-        case v ⇒ throw new IllegalArgumentException("Unsupported scalar value: " + v.toString)
+        case v => throw new IllegalArgumentException("Unsupported scalar value: " + v.toString)
       }
 
     def enumNode(value: String, typeName: String) = JsString(value)
@@ -80,10 +80,10 @@ object SprayMarshallers {
 
     def isDefined(node: JsValue): Boolean = node != JsNull
     def getScalarValue(node: JsValue): Any = node match {
-      case JsBoolean(b) ⇒ b
+      case JsBoolean(b) => b
-      case JsNumber(d) ⇒ d.toBigIntExact getOrElse d
+      case JsNumber(d) => d.toBigIntExact getOrElse d
-      case JsString(s) ⇒ s
+      case JsString(s) => s
-      case n ⇒ n
+      case n => n
     }
 
     def getScalaScalarValue(node: JsValue): Any = getScalarValue(node)
@@ -118,7 +118,7 @@ object SprayMarshallers {
   implicit def sprayJsonWriterToInput[T: JsonWriter]: ToInput[T, JsValue] =
     new ToInput[T, JsValue] {
       def toInput(value: T): (JsValue, CustomSprayJsonInputUnmarshaller.type) =
-        implicitly[JsonWriter[T]].write(value) → CustomSprayJsonInputUnmarshaller
+        implicitly[JsonWriter[T]].write(value) -> CustomSprayJsonInputUnmarshaller
     }
 
   implicit def sprayJsonReaderFromInput[T: JsonReader]: FromInput[T] =
@@ -127,7 +127,7 @@ object SprayMarshallers {
       def fromResult(node: marshaller.Node): T =
         try implicitly[JsonReader[T]].read(node)
         catch {
-          case e: DeserializationException ⇒ throw InputParsingError(Vector(e.msg))
+          case e: DeserializationException => throw InputParsingError(Vector(e.msg))
         }
     }
 

navigator/backend/src/main/scala/com/digitalasset/navigator/graphql/StringAliasType.scala

@@ -19,11 +19,11 @@ object StringAliasType {
       coerceOutput = sangria.schema.valueOutput,
       coerceUserInput = {
         case s: String => Right(s)
-        case _ ⇒ Left(StringCoercionViolation)
+        case _ => Left(StringCoercionViolation)
       },
       coerceInput = {
         case StringValue(s, _, _, _, _) => Right(s)
-        case _ ⇒ Left(StringCoercionViolation)
+        case _ => Left(StringCoercionViolation)
       },
     )
 
@@ -34,11 +34,11 @@ object StringAliasType {
       coerceOutput = (value, _) => Tag.unwrap(value),
       coerceUserInput = {
         case s: String => Right(Tag.of[T](s))
-        case _ ⇒ Left(StringCoercionViolation)
+        case _ => Left(StringCoercionViolation)
       },
       coerceInput = {
         case StringValue(s, _, _, _, _) => Right(Tag.of[T](s))
-        case _ ⇒ Left(StringCoercionViolation)
+        case _ => Left(StringCoercionViolation)
       },
     )
 }

navigator/backend/src/main/scala/com/digitalasset/navigator/json/ApiCodecVerbose.scala

@@ -139,7 +139,7 @@ object ApiCodecVerbose {
       case `tagVariant` => jsValueToApiVariant(value)
       case `tagEnum` => jsValueToApiEnum(value)
       case `tagList` =>
-        V.ValueList(arrayField(value, propValue, "ApiList").map(jsValueToApiValue).to[FrontStack])
+        V.ValueList(arrayField(value, propValue, "ApiList").map(jsValueToApiValue).to(FrontStack))
       case `tagText` => V.ValueText(strField(value, propValue, "ApiText"))
       case `tagInt64` => V.ValueInt64(strField(value, propValue, "ApiInt64").toLong)
       case `tagNumeric` =>
@@ -179,7 +179,7 @@ object ApiCodecVerbose {
           asObject(value, "ApiRecord").fields
             .get(propId)
             .flatMap(_.convertTo[Option[DamlLfIdentifier]]),
-          arrayField(value, propFields, "ApiRecord").map(jsValueToApiRecordField).to[ImmArray],
+          arrayField(value, propFields, "ApiRecord").map(jsValueToApiRecordField).to(ImmArray),
         )
       case t =>
         deserializationError(
@@ -265,5 +265,5 @@ object ApiCodecVerbose {
   }
 
   private[this] def assertDE[A](ea: Either[String, A]): A =
-    ea fold (deserializationError(_), identity)
+    ea.fold(deserializationError(_), identity)
 }

navigator/backend/src/main/scala/com/digitalasset/navigator/model/Ledger.scala

@@ -7,6 +7,7 @@ import com.daml.ledger.api.refinements.ApiTypes
 import com.daml.navigator.data.DatabaseActions
 import com.typesafe.scalalogging.LazyLogging
 
+import scala.collection.compat.immutable.LazyList
 import scala.util.{Failure, Success, Try}
 
 /** In-memory projection of ledger events. */
@@ -274,28 +275,28 @@ case class Ledger(
     }
   }
 
-  def allContracts(types: PackageRegistry): Stream[Contract] = {
+  def allContracts(types: PackageRegistry): LazyList[Contract] = {
     if (useDatabase) {
-      logErrorAndDefaultTo(db.contracts(types), List.empty[Contract]).toStream
+      logErrorAndDefaultTo(db.contracts(types), List.empty[Contract]).to(LazyList)
     } else {
-      contractById.values.toStream
+      contractById.values.to(LazyList)
     }
   }
 
-  def activeContracts(types: PackageRegistry): Stream[Contract] = {
+  def activeContracts(types: PackageRegistry): LazyList[Contract] = {
     if (useDatabase) {
-      logErrorAndDefaultTo(db.activeContracts(types), List.empty[Contract]).toStream
+      logErrorAndDefaultTo(db.activeContracts(types), List.empty[Contract]).to(LazyList)
     } else {
-      activeContractById.values.toStream
+      activeContractById.values.to(LazyList)
     }
   }
 
-  def activeTemplateContractsOf(template: Template, types: PackageRegistry): Stream[Contract] = {
+  def activeTemplateContractsOf(template: Template, types: PackageRegistry): LazyList[Contract] = {
     if (useDatabase) {
       logErrorAndDefaultTo(
         db.activeContractsForTemplate(template.id, types),
         List.empty[Contract],
-      ).toStream
+      ).to(LazyList)
     } else {
       templateContractsOf(template, types).filter(contract =>
         activeContractById.contains(contract.id)
@@ -303,22 +304,22 @@ case class Ledger(
     }
   }
 
-  def templateContractsOf(template: Template, types: PackageRegistry): Stream[Contract] = {
+  def templateContractsOf(template: Template, types: PackageRegistry): LazyList[Contract] = {
     if (useDatabase) {
       logErrorAndDefaultTo(
         db.contractsForTemplate(template.id, types),
         List.empty[Contract],
-      ).toStream
+      ).to(LazyList)
     } else {
-      contractsByTemplateId.getOrElse(template.id, Set.empty).toStream
+      contractsByTemplateId.getOrElse(template.id, Set.empty).to(LazyList)
     }
   }
 
-  def allCommands(types: PackageRegistry): Stream[Command] = {
+  def allCommands(types: PackageRegistry): LazyList[Command] = {
     if (useDatabase) {
-      logErrorAndDefaultTo(db.allCommands(types), List.empty[Command]).toStream
+      logErrorAndDefaultTo(db.allCommands(types), List.empty[Command]).to(LazyList)
     } else {
-      commandById.values.toStream
+      commandById.values.to(LazyList)
     }
   }
 

navigator/backend/src/main/scala/com/digitalasset/navigator/model/PackageRegistry.scala

@@ -7,6 +7,7 @@ import com.daml.navigator.{model => Model}
 import com.daml.ledger.api.refinements.ApiTypes
 import com.daml.lf.{iface => DamlLfIface}
 import com.daml.lf.data.{Ref => DamlLfRef}
+import scala.collection.compat.immutable.LazyList
 
 /** Manages a set of known DAML-LF packages. */
 case class PackageRegistry(
@@ -74,8 +75,8 @@ case class PackageRegistry(
   def pack(id: DamlLfRef.PackageId): Option[DamlLfPackage] =
     packages.get(id)
 
-  def allPackages(): Stream[DamlLfPackage] =
+  def allPackages(): LazyList[DamlLfPackage] =
-    packages.values.toStream
+    packages.values.to(LazyList)
 
   // ------------------------------------------------------------------------------------------------------------------
   // Templates
@@ -96,8 +97,8 @@ case class PackageRegistry(
   def templateCount: Int =
     templates.size
 
-  def allTemplates(): Stream[Template] =
+  def allTemplates(): LazyList[Template] =
-    templates.values.toStream
+    templates.values.to(LazyList)
 
   def templatesByName(topLevelDecl: String): Seq[Template] =
     templates.toList

navigator/backend/src/main/scala/com/digitalasset/navigator/model/PartyState.scala

@@ -8,6 +8,7 @@ import java.util.concurrent.atomic.AtomicReference
 import com.daml.lf.{iface => DamlLfIface}
 import com.daml.ledger.api.refinements.ApiTypes
 import com.daml.navigator.config.UserConfig
+import scala.collection.compat.immutable.LazyList
 import scalaz.Tag
 
 case class State(ledger: Ledger, packageRegistry: PackageRegistry)
@@ -56,5 +57,5 @@ class PartyState(val config: UserConfig) {
 
   override def toString: String = "Party(" + name.toString + ")"
 
-  def contracts(): Stream[Contract] = this.ledger.allContracts(this.packageRegistry)
+  def contracts(): LazyList[Contract] = this.ledger.allContracts(this.packageRegistry)
 }

navigator/backend/src/main/scala/com/digitalasset/navigator/model/converter/Converter.scala

@@ -8,7 +8,7 @@ case object Converter {
   /** Returns the sequence of values, or the last error encountered */
   def sequence[E, T](xs: Seq[Either[E, T]]): Either[E, List[T]] =
     xs.foldRight(Right(Nil): Either[E, List[T]]) { (e, acc) =>
-      for (xs <- acc.right; x <- e.right) yield x :: xs
+      for (xs <- acc; x <- e) yield x :: xs
     }
 
   /** Returns the value of a required protobuf3 field, or RequiredFieldDoesNotExistError if it doesn't exist. */

navigator/backend/src/main/scala/com/digitalasset/navigator/model/converter/LedgerApiV1.scala

@@ -465,10 +465,12 @@ case object LedgerApiV1 {
     final class NotACoid(message: String) extends RuntimeException(message) with NoStackTrace
     // this is 100% cheating as Value should have Traverse instead
     try Right(value mapContractId { coid =>
-      ContractId fromString coid fold (
+      ContractId
-        e => throw new NotACoid(e),
+        .fromString(coid)
-        identity
+        .fold(
-      )
+          e => throw new NotACoid(e),
+          identity,
+        )
     })
     catch { case e: NotACoid => Left(GenericConversionError(e.getMessage)) }
   }

navigator/backend/src/main/scala/com/digitalasset/navigator/store/platform/PlatformStore.scala

@@ -136,7 +136,7 @@ class PlatformStore(
       context.become(
         connected(StateConnected(value.ledgerClient, state.parties, value.staticTime, value.time))
       )
-      unstashAll
+      unstashAll()
 
     case Connected(Failure(e)) =>
       // Connection failed even after several retries - not sure how to recover from this
@@ -147,7 +147,7 @@ class PlatformStore(
       context.become(failed(StateFailed(e)))
 
     case GetApplicationStateInfo =>
-      sender ! ApplicationStateConnecting(
+      sender() ! ApplicationStateConnecting(
         platformHost,
         platformPort,
         tlsConfig.exists(_.enabled),
@@ -155,7 +155,7 @@ class PlatformStore(
       )
 
     case _ =>
-      stash
+      stash()
   }
 
   def connected(state: StateConnected): Receive = {
@@ -192,16 +192,16 @@ class PlatformStore(
       }
 
     case CreateContract(party, templateId, value) =>
-      createContract(state.time.time.getCurrentTime, party, templateId, value, sender)
+      createContract(state.time.time.getCurrentTime, party, templateId, value, sender())
 
     case ExerciseChoice(party, contractId, choiceId, value) =>
-      exerciseChoice(state.time.time.getCurrentTime, party, contractId, choiceId, value, sender)
+      exerciseChoice(state.time.time.getCurrentTime, party, contractId, choiceId, value, sender())
 
     case ReportCurrentTime =>
-      sender ! Success(state.time)
+      sender() ! Success(state.time)
 
     case AdvanceTime(to) =>
-      advanceTime(state.staticTime, to, sender)
+      advanceTime(state.staticTime, to, sender())
 
     case ResetConnection =>
       // Wait for all children to stop, then initiate new connection
@@ -214,7 +214,7 @@ class PlatformStore(
       implicit val actorTimeout: Timeout = Timeout(5, TimeUnit.SECONDS)
 
       // Store the original sender (sender is mutable)
-      val snd = sender
+      val snd = sender()
 
       Future
         .traverse(state.parties.toList) {
@@ -262,7 +262,7 @@ class PlatformStore(
   // Permanently failed state
   def failed(state: StateFailed): Receive = {
     case GetApplicationStateInfo =>
-      sender ! ApplicationStateFailed(
+      sender() ! ApplicationStateFailed(
         platformHost,
         platformPort,
         tlsConfig.exists(_.enabled),

navigator/backend/src/main/scala/com/digitalasset/navigator/store/platform/PlatformSubscriber.scala

@@ -111,10 +111,10 @@ class PlatformSubscriber(
       unstashAll()
 
     case GetPartyActorInfo =>
-      sender ! PartyActorStarting(party)
+      sender() ! PartyActorStarting(party)
 
     case _ =>
-      stash
+      stash()
   }
 
   def running(state: StateRunning): Receive = {
@@ -122,20 +122,20 @@ class PlatformSubscriber(
       log.debug("Resetting connection for '{}'", party.name)
       killSwitch.shutdown()
       context.stop(self)
-      sender ! ConnectionReset
+      sender() ! ConnectionReset
 
     case SubmitCommand(command, commandSender) =>
       // Submit command and reply to
       submitCommand(ledgerClient, state.commandTracker, party, command, commandSender)
 
     case GetPartyActorInfo =>
-      sender ! PartyActorStarted(party)
+      sender() ! PartyActorStarted(party)
   }
 
   // Permanently failed state
   def failed(error: Throwable): Receive = {
     case GetApplicationStateInfo =>
-      sender ! PartyActorFailed(party, error)
+      sender() ! PartyActorFailed(party, error)
 
     case _ => ()
   }

navigator/backend/src/test/scala/com/digitalasset/navigator/backend/DamlConstants.scala

@@ -350,7 +350,7 @@ case object DamlConstants {
   private[navigator] def record(fields: (String, ApiValue)*): ApiRecord =
     V.ValueRecord(
       None,
-      fields.iterator.map { case (label, value) => Some(name(label)) -> value }.to[ImmArray],
+      fields.iterator.map { case (label, value) => Some(name(label)) -> value }.to(ImmArray),
     )
 
 }

navigator/backend/src/test/scala/com/digitalasset/navigator/backend/model/LedgerSpec.scala

@@ -104,13 +104,16 @@ class LedgerSpec extends AnyWordSpec with Matchers {
       }
 
       "return the created contracts when traversing all contracts" in {
-        result.allContracts(templateRegistry) should contain allOf (contract("C1"), contract("C2"))
+        result.allContracts(templateRegistry) should contain.allOf(contract("C1"), contract("C2"))
       }
 
       "consider the created contracts to be active" in {
-        result.activeContracts(templateRegistry) should contain allOf (contract("C1"), contract(
+        result.activeContracts(templateRegistry) should contain.allOf(
-          "C2"
+          contract("C1"),
-        ))
+          contract(
+            "C2"
+          ),
+        )
       }
 
       "return the events by id" in {
@@ -247,7 +250,7 @@ class LedgerSpec extends AnyWordSpec with Matchers {
         actingParties = List(party),
         consuming = true,
       )
-      val latest = transaction("Tx1").copy(events = List(exercisedEvent, createdEvent))
+      val latest = transaction("Tx1").copy(events = List[Event](exercisedEvent, createdEvent))
 
       val result = subject.withTransaction(latest, templateRegistry)
 

navigator/backend/src/test/scala/com/digitalasset/navigator/backend/query/ContractFilterSpec.scala

@@ -121,7 +121,8 @@ class ContractFilterSpec extends AnyFlatSpec with Matchers {
   def test(filters: List[(String, String)], expected: List[Contract], isAnd: Boolean): Unit = {
     it should s"return $expected on filter (${filters.map { case (k, v) => s"$k contains $v" }.mkString(" and ")})" in {
       val criteria = filters.map { case (k, v) => new FilterCriterion(k, v) }
-      val criterion = if (isAnd) AndFilterCriterion(criteria) else OrFilterCriterion(criteria)
+      val criterion: FilterCriterionBase =
+        if (isAnd) AndFilterCriterion(criteria) else OrFilterCriterion(criteria)
       val filter = new ContractFilter(criterion, damlLfDefDataTypes.get, AllContractsPager)
       contracts.filter(filter.isIncluded) should contain theSameElementsAs expected
     }

navigator/integration-test/BUILD.bazel

@@ -15,25 +15,31 @@ da_scala_binary(
     main_class = "com.daml.navigator.test.Main",
     resource_strip_prefix = "navigator/integration-test/src/main/resources/",
     resources = ["src/main/resources/Main.daml"],
+    scala_deps = [
+        "@maven//:com_chuusai_shapeless",
+        "@maven//:com_github_scopt_scopt",
+        "@maven//:com_typesafe_scala_logging_scala_logging",
+        "@maven//:io_circe_circe_core",
+        "@maven//:io_circe_circe_generic",
+        "@maven//:io_circe_circe_parser",
+        "@maven//:org_scalactic_scalactic",
+        "@maven//:org_scalatest_scalatest",
+        "@maven//:org_scalatestplus_selenium_3_141",
+        "@maven//:org_typelevel_cats_core",
+        "@maven//:org_typelevel_cats_kernel",
+    ],
+    versioned_scala_deps = {
+        "2.12": ["@maven//:org_scala_lang_modules_scala_collection_compat"],
+    },
     visibility = ["//visibility:public"],
     runtime_deps = [
         "//ledger/sandbox-classic",
         "@maven//:ch_qos_logback_logback_classic",
     ],
     deps = [
-        "@maven//:com_chuusai_shapeless_2_12",
-        "@maven//:com_github_scopt_scopt_2_12",
-        "@maven//:com_typesafe_scala_logging_scala_logging_2_12",
         "@maven//:commons_codec_commons_codec",
-        "@maven//:io_circe_circe_core_2_12",
-        "@maven//:io_circe_circe_generic_2_12",
-        "@maven//:io_circe_circe_parser_2_12",
-        "@maven//:org_scalactic_scalactic_2_12",
-        "@maven//:org_scalatest_scalatest_2_12",
-        "@maven//:org_scalatestplus_selenium_3_141_2_12",
         "@maven//:org_seleniumhq_selenium_selenium_api",
         "@maven//:org_seleniumhq_selenium_selenium_remote_driver",
         "@maven//:org_slf4j_slf4j_api",
-        "@maven//:org_typelevel_cats_core_2_12",
     ],
 )

navigator/integration-test/src/main/scala/com/digitalasset/navigator/test/BrowserTest.scala

@@ -65,7 +65,7 @@ class BrowserTest(args: Arguments)
 
     // Don't log the actual command, it contains credentials
     logger.info("Running BrowserStackLocal...")
-    Process(commands).run
+    Process(commands).run()
   }
 
   implicit private val webDriver: WebDriver = getBrowserStackDriver() match {

navigator/integration-test/src/main/scala/com/digitalasset/navigator/test/Main.scala

@@ -4,7 +4,7 @@
 package com.daml.navigator.test
 
 import scala.collection._
-import scala.collection.JavaConverters._
+import scala.jdk.CollectionConverters._
 import java.util.concurrent.ConcurrentHashMap
 
 import com.daml.navigator.test.config.Arguments
@@ -22,7 +22,10 @@ object Main extends LazyLogging {
       case Some(arguments) =>
         val reporter = new LoggerReporter()
         val status = new BrowserTest(arguments)
-          .run(None, Args(reporter = reporter, configMap = new ConfigMap(Map.empty[String, Any])))
+          .run(
+            None,
+            Args(reporter = reporter, configMap = new ConfigMap(immutable.Map.empty[String, Any])),
+          )
         val success = Try(status.succeeds()).getOrElse(false)
         val exitCode = if (success) 0 else 1
         val header =