add Scala 2.13 support (#320)

* add Scala 2.13 cross build

* fix HeavyHitters import

* fix breakage

* add 2.13 CircleCI build

* remove parallel collection usage

* scalafmt

* improve CanBuild

* bump version to 0.5.0-SNAPSHOT

Author: nevillelyh

.circleci/config.yml

@@ -8,6 +8,10 @@ scala_212: &scala_212
   environment:
     - SCALA_VERSION: 2.12.10
 
+scala_213: &scala_213
+  environment:
+    - SCALA_VERSION: 2.13.1
+
 jdk8: &jdk8
   docker:
     - image: circleci/openjdk:8-jdk
@@ -69,6 +73,12 @@ jobs:
     - build_featran:
         build-steps:
           - run: sbt "++$SCALA_VERSION test"
+  build_213:
+    <<: [*settings, *scala_213, *jdk8]
+    steps:
+    - build_featran:
+        build-steps:
+          - run: sbt "++$SCALA_VERSION test"
 
   build_212_jdk11:
     <<: [*settings, *scala_212, *jdk11]
@@ -101,11 +111,16 @@ workflows:
       - build_212_jdk11:
           requires:
             - checks
+      - build_213:
+          requires:
+            - checks
+            - mima_report
 
       - publish:
           requires:
             - build_211
             - build_212
+            - build_213
           filters:
             branches:
               only:

build.sbt

@@ -21,7 +21,7 @@ import sbtrelease.ReleaseStateTransformations._
 
 val algebirdVersion = "0.13.6"
 val breezeVersion = "1.0"
-val circeVersion = "0.11.2"
+val circeVersion = "0.12.3"
 val commonsMathVersion = "3.6.1"
 val flinkVersion = "1.9.1"
 val hadoopVersion = "3.2.1"
@@ -44,14 +44,29 @@ lazy val commonSettings = Seq(
   description := "Feature Transformers",
   scalaVersion := "2.12.10",
   scalacOptions ++= commonScalacOptions,
+  scalacOptions ++= {
+    if (scalaBinaryVersion.value == "2.13")
+      Seq("-Ymacro-annotations")
+    else
+      Seq(
+        "-Xfuture",
+        "-Yno-adapted-args"
+      )
+  },
   scalacOptions in (Compile, doc) ++= Seq("-skip-packages", "org.apache"),
   javacOptions ++= Seq("-source", "1.8", "-target", "1.8", "-Xlint:unchecked"),
   javacOptions in (Compile, doc) := Seq("-source", "1.8"),
   testOptions in Test += Tests.Argument(TestFrameworks.ScalaCheck, "-verbosity", "3"),
   libraryDependencies ++= Seq(
-    "org.typelevel" %% "simulacrum" % simulacrumVersion % CompileTime,
-    compilerPlugin("org.scalamacros" %% "paradise" % "2.1.1" cross CrossVersion.full)
+    "org.typelevel" %% "simulacrum" % simulacrumVersion % CompileTime
   ),
+  libraryDependencies ++= {
+    if (scalaBinaryVersion.value == "2.13") {
+      Nil
+    } else {
+      Seq(compilerPlugin("org.scalamacros" %% "paradise" % "2.1.1" cross CrossVersion.full))
+    }
+  },
   ivyConfigurations += CompileTime,
   unmanagedClasspath in Compile ++= update.value.select(configurationFilter(CompileTime.name))
 )
@@ -61,23 +76,11 @@ lazy val publishSettings = Seq(
     username <- sys.env.get("SONATYPE_USERNAME")
     password <- sys.env.get("SONATYPE_PASSWORD")
   } yield Credentials("Sonatype Nexus Repository Manager", "oss.sonatype.org", username, password)).toSeq,
-  publishTo := sonatypePublishToBundle.value,
+  publishTo := Some(
+    if (isSnapshot.value) Opts.resolver.sonatypeSnapshots else Opts.resolver.sonatypeStaging
+  ),
   releaseCrossBuild := true,
   releasePublishArtifactsAction := PgpKeys.publishSigned.value,
-  releaseProcess := Seq[ReleaseStep](
-    checkSnapshotDependencies,
-    inquireVersions,
-    runClean,
-    releaseStepCommandAndRemaining("+test"),
-    setReleaseVersion,
-    commitReleaseVersion,
-    tagRelease,
-    releaseStepCommandAndRemaining("+publishSigned"),
-    releaseStepCommand("sonatypeBundleRelease"),
-    setNextVersion,
-    commitNextVersion,
-    pushChanges
-  ),
   publishMavenStyle := true,
   publishArtifact in Test := false,
   sonatypeProfileName := "com.spotify",
@@ -177,7 +180,7 @@ lazy val core: Project = project
     name := "core",
     moduleName := "featran-core",
     description := "Feature Transformers",
-    crossScalaVersions := Seq("2.11.12", "2.12.10"),
+    crossScalaVersions := Seq("2.11.12", "2.12.10", "2.13.1"),
     libraryDependencies ++= Seq(
       "com.twitter" %% "algebird-core" % algebirdVersion,
       "org.scalanlp" %% "breeze" % breezeVersion,
@@ -189,7 +192,7 @@ lazy val core: Project = project
       "io.circe" %% "circe-core",
       "io.circe" %% "circe-generic",
       "io.circe" %% "circe-parser"
-    ).map(_ % circeVersion)
+    ).map(_ % (if (scalaBinaryVersion.value == "2.11") "0.11.2" else circeVersion))
   )
 
 lazy val java: Project = project
@@ -200,7 +203,7 @@ lazy val java: Project = project
     name := "java",
     moduleName := "featran-java",
     description := "Feature Transformers - java",
-    crossScalaVersions := Seq("2.11.12", "2.12.10"),
+    crossScalaVersions := Seq("2.11.12", "2.12.10", "2.13.1"),
     libraryDependencies ++= Seq(
       "org.scalacheck" %% "scalacheck" % scalacheckVersion % "test",
       "org.scalatest" %% "scalatest" % scalatestVersion % "test"
@@ -300,7 +303,7 @@ lazy val numpy: Project = project
     name := "numpy",
     moduleName := "featran-numpy",
     description := "Feature Transformers - NumPy",
-    crossScalaVersions := Seq("2.11.12", "2.12.10"),
+    crossScalaVersions := Seq("2.11.12", "2.12.10", "2.13.1"),
     libraryDependencies ++= Seq(
       "org.scalatest" %% "scalatest" % scalatestVersion % "test"
     )
@@ -315,7 +318,7 @@ lazy val tensorflow: Project = project
     name := "tensorflow",
     moduleName := "featran-tensorflow",
     description := "Feature Transformers - TensorFlow",
-    crossScalaVersions := Seq("2.11.12", "2.12.10"),
+    crossScalaVersions := Seq("2.11.12", "2.12.10", "2.13.1"),
     libraryDependencies ++= Seq(
       "org.tensorflow" % "proto" % tensorflowVersion,
       "me.lyh" %% "shapeless-datatype-tensorflow" % shapelessDatatypeVersion,
@@ -335,7 +338,7 @@ lazy val xgboost: Project = project
     name := "xgboost",
     moduleName := "featran-xgboost",
     description := "Feature Transformers - XGBoost",
-    crossScalaVersions := Seq("2.11.12", "2.12.10"),
+    crossScalaVersions := Seq("2.11.12", "2.12.10", "2.13.1"),
     libraryDependencies ++= Seq(
       "org.scalacheck" %% "scalacheck" % scalacheckVersion % "test"
     )
@@ -350,7 +353,7 @@ lazy val examples: Project = project
   .settings(featranSettings)
   .settings(soccoSettings)
   .settings(
-    crossScalaVersions := Seq("2.11.12", "2.12.10"),
+    crossScalaVersions := Seq("2.11.12", "2.12.10", "2.13.1"),
     name := "examples",
     moduleName := "featran-examples",
     description := "Feature Transformers - examples",
@@ -388,10 +391,8 @@ lazy val commonScalacOptions = Seq(
   "-language:higherKinds",
   "-language:implicitConversions",
   "-unchecked",
-  "-Yno-adapted-args",
   "-Ywarn-unused",
-  "-Ywarn-dead-code",
-  "-Xfuture"
+  "-Ywarn-dead-code"
 )
 
 lazy val soccoSettings = if (sys.env.contains("SOCCO")) {

core/src/main/scala/com/spotify/featran/CanBuild.scala

@@ -0,0 +1,65 @@
+/*
+ * Copyright 2017 Spotify AB.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package com.spotify.featran
+
+import scala.collection.mutable
+import scala.reflect.ClassTag
+
+// Workaround for CanBuildFrom not serializable
+trait CanBuild[T, M[_]] extends Serializable {
+  def apply(): mutable.Builder[T, M[T]]
+}
+
+object CanBuild {
+  // Collection types in _root_.scala.*
+  implicit def iterableCB[T]: CanBuild[T, Iterable] = new CanBuild[T, Iterable] {
+    override def apply(): mutable.Builder[T, Iterable[T]] = Iterable.newBuilder
+  }
+
+  implicit def seqCB[T]: CanBuild[T, Seq] = new CanBuild[T, Seq] {
+    override def apply(): mutable.Builder[T, Seq[T]] = Seq.newBuilder
+  }
+
+  implicit def indexedSeqCB[T]: CanBuild[T, IndexedSeq] = new CanBuild[T, IndexedSeq] {
+    override def apply(): mutable.Builder[T, IndexedSeq[T]] = IndexedSeq.newBuilder
+  }
+
+  implicit def listCB[T]: CanBuild[T, List] = new CanBuild[T, List] {
+    override def apply(): mutable.Builder[T, List[T]] = List.newBuilder
+  }
+
+  implicit def vectorCB[T]: CanBuild[T, Vector] = new CanBuild[T, Vector] {
+    override def apply(): mutable.Builder[T, Vector[T]] = Vector.newBuilder
+  }
+
+  implicit def bufferCB[T]: CanBuild[T, mutable.Buffer] = new CanBuild[T, mutable.Buffer] {
+    override def apply(): mutable.Builder[T, mutable.Buffer[T]] = mutable.Buffer.newBuilder
+  }
+
+  implicit def floatArrayCB: CanBuild[Float, Array] = new CanBuild[Float, Array] {
+    override def apply(): mutable.Builder[Float, Array[Float]] = Array.newBuilder[Float]
+  }
+
+  implicit def doubleArrayCB: CanBuild[Double, Array] = new CanBuild[Double, Array] {
+    override def apply(): mutable.Builder[Double, Array[Double]] = Array.newBuilder[Double]
+  }
+
+  implicit def arrayCB[T: ClassTag]: CanBuild[T, Array] = new CanBuild[T, Array] {
+    override def apply(): mutable.Builder[T, Array[T]] = Array.newBuilder[T]
+  }
+}

core/src/main/scala/com/spotify/featran/CollectionType.scala

@@ -19,7 +19,6 @@ package com.spotify.featran
 
 import simulacrum._
 
-import scala.collection.generic.CanBuildFrom
 import scala.collection.mutable
 import scala.reflect.ClassTag
 
@@ -38,36 +37,36 @@ import scala.reflect.ClassTag
 }
 
 object CollectionType {
-  implicit def scalaCollectionType[M[_] <: Traversable[_]](
-    implicit cbf: CanBuildFrom[M[_], _, M[_]]
+  implicit def scalaCollectionType[M[_]](
+    implicit cb: CanBuild[_, M],
+    ti: M[_] => Iterable[_]
   ): CollectionType[M] =
     new CollectionType[M] {
       override def map[A, B: ClassTag](ma: M[A])(f: A => B): M[B] = {
-        val builder = cbf().asInstanceOf[mutable.Builder[B, M[B]]]
-        ma.asInstanceOf[Seq[A]].foreach(a => builder += f(a))
+        val builder = cb().asInstanceOf[mutable.Builder[B, M[B]]]
+        ma.asInstanceOf[Iterable[A]].foreach(a => builder += f(a))
         builder.result()
       }
 
       override def pure[A, B: ClassTag](ma: M[A])(b: B): M[B] = {
-        val builder = cbf().asInstanceOf[mutable.Builder[B, M[B]]]
+        val builder = cb().asInstanceOf[mutable.Builder[B, M[B]]]
         builder += b
         builder.result()
       }
 
       override def reduce[A](ma: M[A])(f: (A, A) => A): M[A] = {
-        val builder = cbf().asInstanceOf[mutable.Builder[A, M[A]]]
-        if (ma.asInstanceOf[Seq[A]].nonEmpty) {
-          builder += ma.asInstanceOf[Seq[A]].reduce(f)
+        val builder = cb().asInstanceOf[mutable.Builder[A, M[A]]]
+        if (ma.nonEmpty) {
+          builder += ma.asInstanceOf[Iterable[A]].reduce(f)
         }
         builder.result()
       }
 
       override def cross[A, B: ClassTag](ma: M[A])(mb: M[B]): M[(A, B)] = {
-        val builder = cbf().asInstanceOf[mutable.Builder[(A, B), M[(A, B)]]]
-        val seq = mb.asInstanceOf[Seq[B]]
-        if (seq.nonEmpty) {
-          val b = mb.asInstanceOf[Seq[B]].head
-          ma.asInstanceOf[Seq[A]].foreach(a => builder += ((a, b)))
+        val builder = cb().asInstanceOf[mutable.Builder[(A, B), M[(A, B)]]]
+        if (mb.nonEmpty) {
+          val b = mb.asInstanceOf[Iterable[B]].head
+          ma.asInstanceOf[Iterable[A]].foreach(a => builder += ((a, b)))
         }
         builder.result()
       }

core/src/main/scala/com/spotify/featran/CrossingFeatureBuilder.scala

@@ -46,9 +46,11 @@ private case class Crossings(map: Crossings.MAP, keys: Set[String]) {
 
   def filter[T](predicate: String => Boolean): Crossings = {
     val filteredKeys = keys.filter(predicate)
-    val filteredMap = map.filterKeys {
+    val b = SortedMap.newBuilder[Crossings.KEY, Crossings.FN]
+    b ++= map.filterKeys {
       case (k1, k2) => filteredKeys.contains(k1) || filteredKeys.contains(k2)
     }
+    val filteredMap = b.result()
 
     Crossings(filteredMap, filteredKeys)
   }