Fix Scala 2.13 warnings (#332)

Fix Scala 2.13 warnings

Author: dwijnand

build.sbt

@@ -12,7 +12,7 @@ inThisBuild(Seq(
   git.gitTagToVersionNumber := (tag => if (tag matches "[0.9]+\\..*") Some(tag) else None),
   git.useGitDescribe := true,
   scalaVersion := sys.props.getOrElse("mima.buildScalaVersion", "2.12.8"),
-  scalacOptions := Seq("-feature", "-deprecation", "-Xlint", "-Xfuture"),
+  scalacOptions := Seq("-feature", "-deprecation", "-Xlint"),
   crossScalaVersions := Nil,
 ))
 
@@ -49,6 +49,7 @@ val functionalTests = Project("functional-tests", file("functional-tests"))
   .disablePlugins(BintrayPlugin)
   .settings(
     crossScalaVersions := Seq("2.12.8", "2.13.0"),
+    libraryDependencies += "org.scala-lang.modules" %% "scala-collection-compat" % "2.1.1",
     mimaFailOnNoPrevious := false,
     skip in publish := true,
   )

core/src/main/scala/com/typesafe/tools/mima/core/Config.scala

@@ -28,7 +28,7 @@ object Config {
   lazy val outDir: Directory = {
     assert(!inPlace)
     val f = Path(settings.mimaOutDir.value).toDirectory
-    if (!(f.isDirectory && f.canWrite)) fatal(f + " is not a writable directory")
+    if (!(f.isDirectory && f.canWrite)) fatal(s"$f is not a writable directory")
     f
   }
 

core/src/main/scala/com/typesafe/tools/mima/core/Members.scala

@@ -1,12 +1,9 @@
 package com.typesafe.tools.mima.core
 
 import scala.collection.mutable
-import scala.collection.TraversableOnce
 
-class Members(members: TraversableOnce[MemberInfo]) {
-  private val bindings = new mutable.HashMap[String, List[MemberInfo]] {
-    override def default(key: String) = Nil
-  }
+class Members(members: Iterable[MemberInfo]) {
+  private val bindings = new mutable.HashMap[String, List[MemberInfo]]().withDefaultValue(Nil)
 
   locally {
     for (m <- members)
@@ -17,7 +14,7 @@ class Members(members: TraversableOnce[MemberInfo]) {
 
   def get(name: String): Iterator[MemberInfo] = bindings(name).iterator
 
-  def withoutStatic: Members = new Members(iterator.filterNot(_.isStatic))
+  def withoutStatic: Members = new Members(iterator.filterNot(_.isStatic).toIndexedSeq)
 }
 
 object NoMembers extends Members(Nil)

core/src/main/scala/com/typesafe/tools/mima/core/Settings.scala

@@ -14,7 +14,7 @@ class Settings(specificOptions: String*) extends nsc.Settings(Console.println) {
   val mimaOutDir = StringSetting("-d", "directory", "Specify where to place generated class files", "(change existing)")
   val fixall = BooleanSetting("-fixall", "Fix without asking")
 
-  allSettings += (interactive, mimaOutDir)
+  allSettings ++= Seq(interactive, mimaOutDir)
 
   def visibleNames =
     List(

core/src/main/scala/com/typesafe/tools/mima/lib/analyze/method/MethodChecker.scala

@@ -8,8 +8,8 @@ private[analyze] abstract class BaseMethodChecker extends Checker[MemberInfo, Cl
 
   protected val rules = Seq(AccessModifier, FinalModifier, AbstractModifier, JavaStatic)
 
-  protected def check(method: MemberInfo, in: TraversableOnce[MemberInfo]): Option[Problem] = {
-    val meths = (in.toIterator filter (method.params.size == _.params.size)).toList
+  protected def check(method: MemberInfo, in: Iterator[MemberInfo]): Option[Problem] = {
+    val meths = in.filter(_.params.lengthCompare(method.params.size) == 0).toList
     if (meths.isEmpty)
       Some(DirectMissingMethodProblem(method))
     else {

functional-tests/src/main/scala/com/typesafe/tools/mima/lib/CollectProblemsTest.scala

@@ -18,7 +18,7 @@ class CollectProblemsTest {
     // load test setup
     Config.setup("scala com.typesafe.tools.mima.MiMaLibUI <old-dir> <new-dir>", Array(oldJarPath, newJarPath))
     val cp = testClasspath ++ ClassPath.split(asClassPathString(Config.baseClassPath))
-    val cpString = ClassPath.join(cp: _*)
+    val cpString = ClassPath.join(cp.toIndexedSeq: _*)
     Config.baseClassPath = baseClassPath(cpString)
 
     val mima = new MiMaLib(Config.baseClassPath)

functional-tests/src/main/scala/com/typesafe/tools/mima/lib/ProblemFiltersConfig.scala

@@ -3,7 +3,7 @@ package lib
 
 import com.typesafe.tools.mima.core.{ProblemFilter, ProblemFilters}
 import com.typesafe.config._
-import scala.collection.JavaConverters._
+import scala.jdk.CollectionConverters._
 
 object ProblemFiltersConfig {
   private val filterProblemsPath = "filter.problems"

project/MimaSettings.scala

@@ -38,6 +38,8 @@ object MimaSettings {
       // * com.typesafe.tools.mima.core.Config.setup
       // * com.typesafe.tools.mima.core.reporterClassPath
       // * com.typesafe.tools.mima.lib.MiMaLib.collectProblems
+      exclude[IncompatibleMethTypeProblem]("*mima.lib.analyze.method.BaseMethodChecker.check"), // avoid TraversableOnce for 2.13
+      exclude[IncompatibleMethTypeProblem]("*mima.core.Members.this"),                          // avoid TraversableOnce for 2.13
     ),
   )
 }