Add Scalafix rewrites for 1.0.0

CHANGES.md

@@ -35,7 +35,8 @@ as many breaking changes as possible in this release before we lock down the API
  * `iteratorFoldM` was removed from `Foldable` due to #1716
  * `Split` is removed, and the method `split` is moved to `Arrow`. Note that only under `CommutativeArrow` does it guarantee the non-interference between the effects. see #1567
 
-
+If you feel adventurous you can try the experimental Scalafix rewrites.
+See all the available rewrites and the instructions [here](/scalafix/README.md).
 ### Breaking Changes:
 
  * [#1614](https://github.com/typelevel/cats/pull/1614): added `leftT` and improved existing lift API for `EitherT`. by @kailuowang

scalafix/.scalafmt.conf

@@ -0,0 +1 @@
+align = none

scalafix/README.md

@@ -0,0 +1,45 @@
+# Scalafix rewrites for cats
+
+## Try this!
+
+Install the scalafix sbt plugin (globally or in a specific project):
+
+```scala
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.5.0-M2")
+```
+
+run
+
+```sh
+sbt scalafix github:typelevel/cats/v1.0.0
+```
+
+## Available rewrites
+
+- [x] All Unapply enabled methods, e.g. sequenceU, traverseU, etc. are removed. Unapply enabled syntax ops are also removed. Please use the partial unification SI-2712 fix instead. The easiest way might be this sbt-plugin.
+
+- [x] The creation methods (left, right, apply, pure, etc.) in EitherT were improved to take less type arguments.
+
+- [x] CartesianBuilder (i.e. |@|) syntax is deprecated, use the apply syntax on tuples instead. E.g. (x |@| y |@| z).map(...) should be replaced by (x, y, z).mapN(...)
+
+- [x] Free.suspend is renamed to Free.defer for consistency.
+
+- [x] traverse1_, intercalate1 and sequence1_ in Reducible were renamed to nonEmptyTraverse_, nonEmptyIntercalate and nonEmptySequence_ respectively.
+
+# WIP
+
+- [ ] cats no longer publishes the all-inclusive bundle package "org.typelevel" % "cats", use cats-core, cats-free, or cats-law accordingly instead. If you need cats.free, use "org.typelevel" % "cats-free", if you need cats-laws use "org.typelevel" % "cats-laws", if neither, use "org.typelevel" % "cats-core".
+
+- [ ] cats.free.Inject is moved from cats-free to cats-core and renamed to cats.InjectK; cats.data.Prod is renamed to cats.data.Tuple2K; cats.data.Coproduct is renamed to cats.data.EitherK
+
+- [ ] FunctorFilter, MonadCombine, MonadFilter, MonadReader, MonadState, MonadTrans, MonadWriter and TraverseFilter are no longer in cats, the functionalities they provided are inhereted by the new cats-mtl project. Please check here for migration guide.
+
+- [ ] Apply syntax on tuple (e.g. (x, y, z).map3(...)) was moved from cats.syntax.tuple._ to cats.syntax.apply._ and renamed to mapN, contramapN and imapN respectively.
+
+- [ ] Several cats-core type class instances for cats.kernel were moved from their companion objects to separate traits and thus require imports from cats.instances.xxx._ (or the recommended import cats.implicits._) now. See #1659 for more details.
+
+- [ ] foldLeftM is removed from Free, use foldM on Foldable instead, see #1117 for detail.
+
+- [ ] iteratorFoldM was removed from Foldable due to #1716
+
+- [ ] Split is removed, and the method split is moved to Arrow. Note that only under CommutativeArrow does it guarantee the non-interference between the effects. see #1567

scalafix/build.sbt

@@ -0,0 +1,36 @@
+// Use a scala version supported by scalafix.
+scalaVersion in ThisBuild := org.scalameta.BuildInfo.supportedScalaVersions.last
+
+lazy val rewrites = project.settings(
+  libraryDependencies += "ch.epfl.scala" %% "scalafix-core" % "0.5.0-M1"
+)
+
+lazy val input = project.settings(
+  scalametaSourceroot := sourceDirectory.in(Compile).value,
+  libraryDependencies ++= Seq(
+    "org.typelevel" %% "cats" % "0.9.0"
+  )
+)
+
+lazy val output = project.settings(
+  libraryDependencies ++= Seq(
+    "org.typelevel" %% "cats-core" % "1.0.0-MF",
+    "org.typelevel" %% "cats-free" % "1.0.0-MF"
+  )
+)
+
+lazy val tests = project
+  .settings(
+    libraryDependencies += "ch.epfl.scala" % "scalafix-testkit" % "0.5.0-M1" % Test cross CrossVersion.full,
+    buildInfoPackage := "fix",
+    buildInfoKeys := Seq[BuildInfoKey](
+      "inputSourceroot" ->
+        sourceDirectory.in(input, Compile).value,
+      "outputSourceroot" ->
+        sourceDirectory.in(output, Compile).value,
+      "inputClassdirectory" ->
+        classDirectory.in(input, Compile).value
+    )
+  )
+  .dependsOn(input, rewrites)
+  .enablePlugins(BuildInfoPlugin)

scalafix/input/src/main/scala/fix/v1_0_0/RemoveCartesianBuilder.scala

@@ -0,0 +1,41 @@
+/*
+rewrite = "scala:fix.v1_0_0.RemoveCartesianBuilder"
+ */
+package fix
+package to1_0_0
+
+object RemoveCartesianBuilderTests {
+  {
+    import cats.instances.option._
+    import cats.instances.int._
+    import cats.syntax.cartesian._
+    import cats.syntax.semigroup._
+    val o1: Option[Int] = Some(42)
+    val o2: Option[String] = Some("hello")
+    val o3: Option[Int] = Some(2)
+    (o1 |@| o2).map((i: Int, s: String) => i.toString ++ s)
+    (o1 |@| o2).tupled
+    (o1 |@| o2 |@| o3).map(_ + _ + _)
+    (o1 |+| o1 |@| o3).map(_ + _)
+    o1 |@| o2 |@| o3 map (_ + _ + _)
+    (o1 |+| o1 |@| o3) map (_ + _)
+    o1 |+| o1 |@| o3 map (_ + _)
+
+    (o1 |@|
+     o2 |@|
+     o3) map (_ + _ + _)
+  }
+
+  {
+    import cats.{Semigroup, Eq}
+    import cats.implicits._
+    case class Foo(a: String, c: List[Double])
+
+    (Semigroup[String] |@| Semigroup[List[Double]])
+      .imap(Foo.apply)(Function.unlift(Foo.unapply))
+
+    (Eq[Double] |@| Eq[String]).contramap { (a: Foo) =>
+      (2, "bar")
+    }
+  }
+}

scalafix/input/src/main/scala/fix/v1_0_0/RemoveCartesianBuilder2.scala

@@ -0,0 +1,15 @@
+/* ONLY
+rewrite = "scala:fix.v1_0_0.RemoveCartesianBuilder"
+ */
+package fix
+package to1_0_0
+
+object RemoveCartesianBuilderTests2 {
+  import cats.instances.all._
+  import cats.syntax.cartesian._
+  val o1: Option[Int] = Some(2)
+  val o2: Option[Int] = Some(2)
+  o1 *> o2
+  (o1 |@| o2).map(_ + _)
+}
+

scalafix/input/src/main/scala/fix/v1_0_0/RemoveUnapply.scala

@@ -0,0 +1,44 @@
+/* 
+rewrite = "scala:fix.v1_0_0.RemoveUnapply"
+ */
+package fix
+package to1_0_0
+
+object RemoveUnapplyTests {
+  import cats.implicits._
+  import cats.Foldable
+  def parseInt(s: String): Either[String, Int] =
+    Either.catchOnly[NumberFormatException](s.toInt).leftMap(_ => "no number")
+  val ns = List("1", "2", "3")
+  ns.traverseU(parseInt)
+  ns.traverseU_(parseInt)
+  Foldable[List].traverseU_(ns)(parseInt)
+
+  import cats.data.{Validated, ValidatedNel}
+  val x: List[ValidatedNel[String, Int]] =
+    List(Validated.valid(1), Validated.invalid("a"), Validated.invalid("b"))
+      .map(_.toValidatedNel)
+  x.sequenceU
+  x.sequenceU_
+  Foldable[List].sequenceU_(x)
+
+  import cats.data.Func.{appFuncU, appFunc}
+  import cats.data.State.{get, set}
+  import cats.data.Const
+  type Count[A] = Const[Int, A]
+  def liftInt(i: Int): Count[Unit] = Const(i)
+  def isSpace(c: Char): Boolean = (c == ' ' || c == '\n')
+  def testIf(b: Boolean): Int = if (b) 1 else 0
+  appFuncU { (c: Char) =>
+    for {
+      x <- get[Boolean]
+      y = !isSpace(c)
+      _ <- set(y)
+    } yield testIf(y && !x)
+  } andThen appFunc(liftInt)
+
+  import cats.free.FreeT
+  val a: Either[String, Int] = Right(42)
+  FreeT.liftTU(a)
+
+}

scalafix/input/src/main/scala/fix/v1_0_0/RenameFreeSuspend.scala

@@ -0,0 +1,14 @@
+/* 
+rewrite = "scala:fix.v1_0_0.RenameFreeSuspend"
+ */
+package fix
+package to1_0_0
+
+object RenameFreeSuspendTests {
+  import cats.free.{Free, Trampoline}
+
+  val x = Free.pure[Option, Int](2)
+  Free.suspend(x)
+
+  Trampoline.suspend(Trampoline.done(2))
+}

scalafix/input/src/main/scala/fix/v1_0_0/RenameReducibleMethods.scala

@@ -0,0 +1,22 @@
+/* 
+rewrite = "scala:fix.v1_0_0.RenameReducibleMethods"
+ */
+package fix
+package to1_0_0
+
+object RenameReducibleMethodsTests {
+  import cats.data.NonEmptyList
+  import cats.Reducible
+  import cats.syntax.reducible._
+  import cats.instances.all._
+
+  val ns = NonEmptyList(1, List(2, 3))
+  Reducible[NonEmptyList].traverse1_(ns)(Option.apply)
+  ns.traverse1_(Option.apply)
+
+  Reducible[NonEmptyList].intercalate1(ns, 0)
+  ns.intercalate1(0)
+
+  Reducible[NonEmptyList].sequence1_(ns.map(Option.apply))
+  ns.map(Option.apply).sequence1_
+}

scalafix/input/src/main/scala/fix/v1_0_0/SimplifyEitherTLift.scala

@@ -0,0 +1,14 @@
+/*
+rewrite = "scala:fix.v1_0_0.SimplifyEitherTLift"
+ */
+package fix
+package to1_0_0
+
+object SimplifyEitherTLiftTests {
+  import cats.Id
+  import cats.data.EitherT
+  val eithert = EitherT.left[Id, String, Int]("eithert")
+  eithert.recoverWith {
+    case "eithert" => EitherT.right[Id, String, Int](5)
+  }.isRight
+}

scalafix/output/src/main/scala/fix/v1_0_0/RemoveCartesianBuilder.scala

@@ -0,0 +1,38 @@
+package fix
+package to1_0_0
+
+object RemoveCartesianBuilderTests {
+  {
+    import cats.instances.option._
+    import cats.instances.int._
+    import cats.syntax.apply._
+    import cats.syntax.semigroup._
+    val o1: Option[Int] = Some(42)
+    val o2: Option[String] = Some("hello")
+    val o3: Option[Int] = Some(2)
+    (o1, o2).mapN((i: Int, s: String) => i.toString ++ s)
+    (o1, o2).tupled
+    (o1, o2, o3).mapN(_ + _ + _)
+    (o1 |+| o1, o3).mapN(_ + _)
+    (o1, o2, o3) mapN (_ + _ + _)
+    (o1 |+| o1, o3) mapN (_ + _)
+    (o1 |+| o1, o3) mapN (_ + _)
+
+    (o1,
+     o2,
+     o3) mapN (_ + _ + _)
+  }
+
+  {
+    import cats.{Semigroup, Eq}
+    import cats.implicits._
+    case class Foo(a: String, c: List[Double])
+
+    (Semigroup[String], Semigroup[List[Double]])
+      .imapN(Foo.apply)(Function.unlift(Foo.unapply))
+
+    (Eq[Double], Eq[String]).contramapN { (a: Foo) =>
+      (2, "bar")
+    }
+  }
+}

scalafix/output/src/main/scala/fix/v1_0_0/RemoveCartesianBuilder2.scala

@@ -0,0 +1,13 @@
+package fix
+package to1_0_0
+
+object RemoveCartesianBuilderTests2 {
+  import cats.instances.all._
+  import cats.syntax.cartesian._
+  import cats.syntax.apply._
+  val o1: Option[Int] = Some(2)
+  val o2: Option[Int] = Some(2)
+  o1 *> o2
+  (o1, o2).mapN(_ + _)
+}
+

scalafix/output/src/main/scala/fix/v1_0_0/RemoveUnapply.scala

@@ -0,0 +1,41 @@
+package fix
+package to1_0_0
+
+object RemoveUnapplyTests {
+  import cats.implicits._
+  import cats.Foldable
+  def parseInt(s: String): Either[String, Int] =
+    Either.catchOnly[NumberFormatException](s.toInt).leftMap(_ => "no number")
+  val ns = List("1", "2", "3")
+  ns.traverse(parseInt)
+  ns.traverse_(parseInt)
+  Foldable[List].traverse_(ns)(parseInt)
+
+  import cats.data.{Validated, ValidatedNel}
+  val x: List[ValidatedNel[String, Int]] =
+    List(Validated.valid(1), Validated.invalid("a"), Validated.invalid("b"))
+      .map(_.toValidatedNel)
+  x.sequence
+  x.sequence_
+  Foldable[List].sequence_(x)
+
+  import cats.data.Func.appFunc
+  import cats.data.State.{get, set}
+  import cats.data.Const
+  type Count[A] = Const[Int, A]
+  def liftInt(i: Int): Count[Unit] = Const(i)
+  def isSpace(c: Char): Boolean = (c == ' ' || c == '\n')
+  def testIf(b: Boolean): Int = if (b) 1 else 0
+  appFunc { (c: Char) =>
+    for {
+      x <- get[Boolean]
+      y = !isSpace(c)
+      _ <- set(y)
+    } yield testIf(y && !x)
+  } andThen appFunc(liftInt)
+
+  import cats.free.FreeT
+  val a: Either[String, Int] = Right(42)
+  FreeT.liftT(a)
+
+}

scalafix/output/src/main/scala/fix/v1_0_0/RenameFreeSuspend.scala

@@ -0,0 +1,11 @@
+package fix
+package to1_0_0
+
+object RenameFreeSuspendTests {
+  import cats.free.{Free, Trampoline}
+
+  val x = Free.pure[Option, Int](2)
+  Free.defer(x)
+
+  Trampoline.defer(Trampoline.done(2))
+}

scalafix/output/src/main/scala/fix/v1_0_0/RenameReducibleMethods.scala

@@ -0,0 +1,19 @@
+package fix
+package to1_0_0
+
+object RenameReducibleMethodsTests {
+  import cats.data.NonEmptyList
+  import cats.Reducible
+  import cats.syntax.reducible._
+  import cats.instances.all._
+
+  val ns = NonEmptyList(1, List(2, 3))
+  Reducible[NonEmptyList].nonEmptyTraverse_(ns)(Option.apply)
+  ns.nonEmptyTraverse_(Option.apply)
+
+  Reducible[NonEmptyList].nonEmptyIntercalate(ns, 0)
+  ns.nonEmptyIntercalate(0)
+
+  Reducible[NonEmptyList].nonEmptySequence_(ns.map(Option.apply))
+  ns.map(Option.apply).nonEmptySequence_
+}

scalafix/output/src/main/scala/fix/v1_0_0/SimplifyEitherTLift.scala

@@ -0,0 +1,11 @@
+package fix
+package to1_0_0
+
+object SimplifyEitherTLiftTests {
+  import cats.Id
+  import cats.data.EitherT
+  val eithert = EitherT.leftT[Id, Int]("eithert")
+  eithert.recoverWith {
+    case "eithert" => EitherT.pure[Id, String](5)
+  }.isRight
+}

scalafix/project/build.properties

@@ -0,0 +1 @@
+sbt.version=0.13.13

scalafix/project/plugins.sbt

@@ -0,0 +1,5 @@
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.5.0-M1")
+addSbtPlugin("ch.epfl.scala" % "sbt-scalafix" % "0.5.0-M1")
+addSbtPlugin("io.get-coursier" % "sbt-coursier" % "1.0.0-RC3")
+addSbtPlugin("com.eed3si9n" % "sbt-buildinfo" % "0.6.1")
+addSbtPlugin("org.lyranthe.sbt" % "partial-unification" % "1.0.0")