Merge pull request #1061 from yadavan88/scala-core-migration-scala3

Scala 3 Migration of modules

Author: lor6

build.sbt

@@ -25,10 +25,10 @@ val zioVersion = "2.0.19"
 lazy val scala_core = (project in file("scala-core-modules/scala-core"))
   .settings(
     name := "scala-core",
+    scalaVersion := scala3Version,
     libraryDependencies ++=
       Seq(
-        jUnitInterface,
-        catsEffect
+        jUnitInterface
       ) ++ scalaTestDeps
   )
 
@@ -43,15 +43,32 @@ lazy val scala_core_2 = (project in file("scala-core-modules/scala-core-2"))
 lazy val scala_core_3 = (project in file("scala-core-modules/scala-core-3"))
   .settings(
     name := "scala-core-3",
+    scalaVersion := scala3Version,
     libraryDependencies ++= scalaTestDeps,
     libraryDependencies += jUnitInterface,
-    libraryDependencies += scalaReflection,
     libraryDependencies += "org.scala-lang.modules" %% "scala-xml" % "2.2.0"
   )
 
+lazy val scala2_core = (project in file("scala-core-modules/scala2-core"))
+  .settings(
+    name := "scala2-core",
+    libraryDependencies ++= scalaTestDeps,
+    libraryDependencies += jUnitInterface,
+    libraryDependencies += scalaReflection,
+    libraryDependencies += "org.scala-lang.modules" %% "scala-xml" % "2.2.0",
+    libraryDependencies += "com.github.scopt" %% "scopt" % "4.1.0",
+    libraryDependencies += "org.rogach" %% "scallop" % "5.0.1",
+    libraryDependencies += "org.backuity.clist" %% "clist-core" % "3.5.1",
+    libraryDependencies += "org.backuity.clist" %% "clist-macros" % "3.5.1" % "provided",
+    libraryDependencies += "args4j" % "args4j" % "2.33",
+    libraryDependencies += "org.scala-lang" % "scala-compiler" % scalaVersion.value % "test",
+    libraryDependencies += catsEffect
+  )
+
 lazy val scala_core_4 = (project in file("scala-core-modules/scala-core-4"))
   .settings(
     name := "scala-core-4",
+    scalaVersion := scala3Version,
     libraryDependencies ++= scalaTestDeps,
     libraryDependencies += jUnitInterface,
     libraryDependencies += scalaReflection
@@ -60,36 +77,32 @@ lazy val scala_core_4 = (project in file("scala-core-modules/scala-core-4"))
 lazy val scala_core_5 = (project in file("scala-core-modules/scala-core-5"))
   .settings(
     name := "scala-core-5",
+    scalaVersion := scala3Version,
     libraryDependencies ++= scalaTestDeps,
-    libraryDependencies += jUnitInterface,
-    libraryDependencies += scalaReflection
+    libraryDependencies += jUnitInterface
   )
 
 lazy val scala_core_6 = (project in file("scala-core-modules/scala-core-6"))
   .settings(
     name := "scala-core-6",
+    scalaVersion := scala3Version,
     libraryDependencies ++= scalaTestDeps,
     libraryDependencies += jUnitInterface
   )
 
 lazy val scala_core_7 = (project in file("scala-core-modules/scala-core-7"))
   .settings(
     name := "scala-core-7",
+    scalaVersion := scala3Version,
     libraryDependencies ++= scalaTestDeps,
     libraryDependencies += jUnitInterface,
-    libraryDependencies += "com.github.scopt" %% "scopt" % "4.1.0",
-    libraryDependencies += "org.rogach" %% "scallop" % "5.0.1",
-    libraryDependencies += "org.backuity.clist" %% "clist-core" % "3.5.1",
-    libraryDependencies += "org.backuity.clist" %% "clist-macros" % "3.5.1" % "provided",
-    libraryDependencies += "args4j" % "args4j" % "2.33"
   )
 
 lazy val scala_core_8 = (project in file("scala-core-modules/scala-core-8"))
   .settings(
     name := "scala-core-8",
-    libraryDependencies += scalaReflection,
     libraryDependencies ++= scalaTestDeps,
-    libraryDependencies += "org.scala-lang" % "scala-compiler" % scalaVersion.value % "test",
+    scalaVersion := scala3Version,
     libraryDependencies += "org.scala-lang.modules" %% "scala-java8-compat" % "1.0.2",
     libraryDependencies += "com.typesafe" % "config" % "1.2.1"
     // scalacOptions += "-Ymacro-debug-lite"
@@ -106,6 +119,7 @@ lazy val scala_core_io = (project in file("scala-core-modules/scala-core-io"))
 lazy val scala_core_oop = (project in file("scala-core-modules/scala-core-oop"))
   .settings(
     name := "scala-core-oop",
+    scalaVersion := scala3Version,
     libraryDependencies ++=
       Seq(catsEffect, jUnitInterface) ++ scalaTestDeps
   )

scala-core-modules/scala-core-2/src/test/scala/com/baeldung/scala/exceptionhandling/ExceptionHandlingUnitTest.scala

@@ -1,11 +1,6 @@
 package com.baeldung.scala.exceptionhandling
 
-import com.baeldung.scala.exceptionhandling.ExceptionHandling.{
-  DivideByZero,
-  divideWithEither,
-  divideWithOption,
-  divideWithTry
-}
+import com.baeldung.scala.exceptionhandling.ExceptionHandling._
 import org.scalatest.flatspec.AnyFlatSpec
 import org.scalatest.matchers.should.Matchers
 

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/accessmodifiers/Figure.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/accessmodifiers/Figure.scala

@@ -8,19 +8,19 @@ class TaskUnitTest extends AnyFlatSpec with Matchers {
   "Task" should "be instantiated with default constructor" in {
     val task = new Task("do something")
     task.description should be("do something")
-    task.status should be("pending")
+    task.status() should be("pending")
   }
 
   it should "be able to construct without new keywork" in {
     val task = Task("do something")
     task.description should be("do something")
-    task.status should be("pending")
+    task.status() should be("pending")
   }
 
   it should "have a contructor with status parameter" in {
     val task = Task("do something", "started")
     task.description should be("do something")
-    task.status should be("started")
+    task.status() should be("started")
   }
 
   it should "extract status" in {

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/accessmodifiers/Star.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/accessmodifiers/Star.scala

@@ -1,17 +1,18 @@
 package com.baeldung.scala.structuraltypes
 
 import scala.io.Source
+import scala.language.reflectiveCalls
 
 trait ResourceClosing {
   type Closable = { def close(): Unit }
 
-  def using(resource: Closable)(fn: () => Unit) {
+  def using(resource: Closable)(fn: () => Unit) = {
     try {
       fn()
     } finally { resource.close() }
   }
 
-  def using(file: Source)(fn: () => Unit) {
+  def using(file: Source)(fn: () => Unit) = {
     try {
       fn()
     } finally { file.close() }

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/await/AwaitFuture.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/await/AwaitFuture.scala

@@ -3,6 +3,8 @@ package com.baeldung.scala.structuraltypes
 import org.scalatest.flatspec.AnyFlatSpec
 import org.scalatest.matchers.should.Matchers
 
+import scala.language.reflectiveCalls
+
 class DuckUnitTest extends AnyFlatSpec with Matchers {
   type Flyer = { def fly(): Unit }
   def callFly(thing: Flyer): Unit = thing.fly()

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/companionobject/Task.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/companionobject/Task.scala

@@ -6,9 +6,9 @@ object MegamorphicCallsite extends App {
     fun(n) // callsite
   }
 
-  val f1 = { n: Int => n * n }
-  val f2 = { n: Int => n + n }
-  val f3 = { n: Int => n }
+  val f1 = { (n: Int) => n * n }
+  val f2 = { (n: Int) => n + n }
+  val f3 = { (n: Int) => n }
 
   execute(f1)(5)
   execute(f2)(5)

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/implicitparameter/ImplicitParameter.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/implicitparameter/ImplicitParameter.scala

@@ -7,5 +7,7 @@ object VectorBasics extends App {
   val vecAppended: Vector[Int] = vec :+ 4
   val vecPrepended: Vector[Int] = 0 +: vec
 
-  println(vec, vecPrepended, vecAppended)
+  println(vec)
+  println(vecPrepended)
+  println(vecAppended)
 }

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/iteratorsvsstreamsvsviews/NonStrictDataStructures.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/iteratorsvsstreamsvsviews/NonStrictDataStructures.scala

@@ -31,3 +31,6 @@ case class GuitarBuilder private (
     delay = delay
   )
 }
+object GuitarBuilder {
+  def apply(): GuitarBuilder = new GuitarBuilder()
+}

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/options/OptionBuilder.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/options/OptionBuilder.scala

@@ -20,7 +20,7 @@ object ObjectExample extends App {
   }
 
   // Throws exception in case we call FlyingObject other than airplane and bird
-  def nonExhaustive(objects: FlyingObject.Value) {
+  def nonExhaustive(objects: FlyingObject.Value) = {
     objects match {
       case FlyingObject.airplane => println("I am an airplane")
       case FlyingObject.bird     => println("I am a bird")

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/options/OptionExample.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/options/OptionExample.scala

@@ -5,15 +5,15 @@ object ClassExamples {
   val constA = "A"
   val constB = 4
   class Abc(var a: String, var b: Int) {
-    def this(a: String) {
+    def this(a: String) = {
       this(a, constB)
       this.a = a
     }
-    def this(b: Int) {
+    def this(b: Int) = {
       this(constA, b)
       this.b = b
     }
-    def this() {
+    def this() = {
       this(constA, constB)
     }
   }

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/options/Player.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/options/Player.scala

@@ -18,7 +18,7 @@ class Score(
 
   override def produce(): String = s"The score is produced by $engineer"
 
-  override def algorithm(): MixingAlgorithm = {
+  override def algorithm: MixingAlgorithm = {
     if (qualityRatio < 3) LowInstrumentalQuality
     else super.algorithm
   }

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/options/Tournament.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/options/Tournament.scala

@@ -46,7 +46,7 @@ class ScoreUnitTest {
     val studio = "Abbey Studios"
     val score = new Score(composer, engineer, orchestra, mixer, 1, studio)
 
-    assertEquals(score.algorithm().toString, "Low instrumental quality")
+    assertEquals(score.algorithm.toString, "Low instrumental quality")
   }
 
   @Test
@@ -59,7 +59,7 @@ class ScoreUnitTest {
     val studio = "Abbey Studios"
     val score = new Score(composer, engineer, orchestra, mixer, 10, studio)
 
-    assertEquals(score.algorithm().toString, "High instrumental quality")
+    assertEquals(score.algorithm.toString, "High instrumental quality")
   }
 
   @Test

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/scaladoc/Carnivore.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/scaladoc/Carnivore.scala

@@ -16,8 +16,9 @@ class TuplesUnitTest extends AnyWordSpec with Matchers {
       name shouldBe "Joe"
       age shouldBe 34
     }
-    "not contain more then 22 elements" in {
-      "(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)" shouldNot compile
+    // From Scala3 onwards, we can have more than 22 fields in tuple.
+    "allow more then 22 elements in Scala 3" in {
+      "(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)" should compile
     }
   }
 }

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/scaladoc/IntervalTimer.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/scaladoc/IntervalTimer.scala

@@ -1,10 +1,6 @@
 package com.baeldung.scala.exceptionhandling
 
-import com.baeldung.scala.exceptionhandling.LegacyErrors.{
-  ResourceNotFound,
-  ServerError,
-  UserNotFound
-}
+import com.baeldung.scala.exceptionhandling.LegacyErrors._
 
 import scala.util.{Failure, Success, Try}
 

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/scaladoc/TasmanianDevil.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/scaladoc/TasmanianDevil.scala

@@ -3,11 +3,7 @@ package com.baeldung.scala.exceptionhandling
 import cats.MonadError
 import cats.syntax.flatMap._
 import cats.syntax.functor._
-import com.baeldung.scala.exceptionhandling.LegacyErrors.{
-  ResourceNotFound,
-  ServerError,
-  UserNotFound
-}
+import com.baeldung.scala.exceptionhandling.LegacyErrors._
 
 import scala.util.{Failure, Success, Try}
 

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/scaladoc/package.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/scaladoc/package.scala

@@ -3,10 +3,7 @@ package com.baeldung.scala.exceptionhandling
 import cats.data.ValidatedNel
 import cats.syntax.apply._
 import cats.syntax.validated._
-import com.baeldung.scala.exceptionhandling.ValidationErrors.{
-  IllegalLogin,
-  IllegalPassword
-}
+import com.baeldung.scala.exceptionhandling.ValidationErrors._
 
 object HandlingWithValidated {
   type InvalidOr[T] = ValidatedNel[ValidationErrors, T]

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/typecasts/ErrorHandling.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/typecasts/ErrorHandling.scala

@@ -1,5 +1,7 @@
 package com.baeldung.scala.uniontypes
 
+import scala.language.implicitConversions
+
 object ArbitraryArityUnionType extends App {
 
   def isIntOrStringOrBool[T: IntOrStringOrBool](t: T): String = t match {

scala-core-modules/scala-core-3/src/main/scala-2/com/baeldung/scala/typecasts/TypeErasure.scala renamed to scala-core-modules/scala-core-3/src/main/scala/com/baeldung/scala/typecasts/TypeErasure.scala

@@ -2,15 +2,8 @@ package com.baeldung.scala.exceptionhandling
 
 import cats.data.NonEmptyList
 import cats.data.Validated.{Invalid, Valid}
-import com.baeldung.scala.exceptionhandling.LegacyErrors.{
-  ResourceNotFound,
-  ServerError,
-  UserNotFound
-}
-import com.baeldung.scala.exceptionhandling.ValidationErrors.{
-  IllegalLogin,
-  IllegalPassword
-}
+import com.baeldung.scala.exceptionhandling.LegacyErrors._
+import com.baeldung.scala.exceptionhandling.ValidationErrors._
 import org.scalatest.GivenWhenThen
 import org.scalatest.featurespec.AnyFeatureSpec
 import org.scalatest.matchers.should.Matchers