Magnolia derivation for Debug typeclass

build.sbt

@@ -48,7 +48,9 @@ val projectsCommon = List(
   experimentalLaws,
   experimentalTests,
   laws,
-  macros
+  macros,
+  magnolia,
+  magnoliaTests
 )
 
 val projectsJvmOnly = List[ProjectReference](
@@ -161,6 +163,37 @@ lazy val macros = crossProject(JSPlatform, JVMPlatform, NativePlatform)
   .nativeSettings(nativeSettings)
   .enablePlugins(BuildInfoPlugin)
 
+lazy val magnolia = crossProject(JSPlatform, JVMPlatform, NativePlatform)
+  .in(file("magnolia"))
+  .dependsOn(core)
+  .settings(stdSettings("zio-prelude-magnolia"))
+  .settings(crossProjectSettings)
+  .settings(macroDefinitionSettings)
+  .settings(Compile / console / scalacOptions ~= { _.filterNot(Set("-Xfatal-warnings")) })
+  .settings(buildInfoSettings("zio.prelude.magnolia"))
+  .settings(testFrameworks := Seq(new TestFramework("zio.test.sbt.ZTestFramework")))
+  .settings(dottySettings)
+  .settings(magnoliaSettings)
+  .settings(libraryDependencies += "dev.zio" %%% "zio-test-sbt" % zioVersion % Test)
+  .jvmSettings(scalaReflectTestSettings)
+  .jsSettings(jsSettings)
+  .nativeSettings(nativeSettings)
+  .enablePlugins(BuildInfoPlugin)
+
+lazy val magnoliaTests = crossProject(JSPlatform, JVMPlatform, NativePlatform)
+  .in(file("magnolia-tests"))
+  .dependsOn(magnolia)
+  .settings(stdSettings("zio-prelude-magnolia-tests"))
+  .settings(crossProjectSettings)
+  .settings(buildInfoSettings("zio.prelude.magnolia.tests"))
+  .settings(testFrameworks := Seq(new TestFramework("zio.test.sbt.ZTestFramework")))
+  .settings(dottySettings)
+  .settings(libraryDependencies += "dev.zio" %%% "zio-test-sbt" % zioVersion % Test)
+  .jvmSettings(scalaReflectTestSettings)
+  .jsSettings(jsSettings)
+  .nativeSettings(nativeSettings)
+  .enablePlugins(BuildInfoPlugin)
+
 lazy val experimental = crossProject(JSPlatform, JVMPlatform, NativePlatform)
   .in(file("experimental"))
   .dependsOn(core)

magnolia-tests/shared/src/test/scala/zio/debug/magnolia/DeriveDebugSpec.scala

@@ -0,0 +1,56 @@
+package zio.debug.magnolia
+
+import zio.Scope
+import zio.prelude._
+import zio.test.Assertion._
+import zio.test.{ZIOSpecDefault, _}
+
+case class Lair(name: String, animal: Animal)
+
+object Lair {
+  implicit val debug: Debug[Lair] = DeriveDebug.derived[Lair]
+}
+
+case class Animal(name: String, age: Int)
+
+object Animal {
+  implicit val debug: Debug[Animal] = DeriveDebug.derived[Animal]
+}
+
+case class Adult(name: String, age: Int, chidren: List[Child])
+case class Child(name: String, age: Int)
+
+object Adult {
+  implicit val debug: Debug[Adult] = DeriveDebug.derived[Adult]
+}
+
+object Child {
+  implicit val debug: Debug[Child] = DeriveDebug.derived[Child]
+}
+
+object Test extends ZIOSpecDefault {
+
+  override def spec: Spec[TestEnvironment with Scope, Any] =
+    suite("DeriveDebug")(
+      test("should derive Debug for case class") {
+        val animal = Animal("tiger", 10)
+
+        assert(animal.debug.render)(equalTo("Animal(name = \"tiger\", age = 10)"))
+
+      },
+      test("should derive Debug for nested case class") {
+        val lair = Lair("jungle", Animal("tiger", 10))
+
+        assert(lair.debug.render)(equalTo("Lair(name = \"jungle\", animal = Animal(name = \"tiger\", age = 10))"))
+      },
+      test("should derive Debug for case class with list") {
+        val adult = Adult("John", 30, List(Child("Alice", 5), Child("Bob", 10)))
+
+        assert(adult.debug.render)(
+          equalTo(
+            "Adult(name = \"John\", age = 30, chidren = List(Child(name = \"Alice\", age = 5), Child(name = \"Bob\", age = 10)))"
+          )
+        )
+      }
+    )
+}

magnolia/shared/src/main/scala-2/zio/debug/magnolia/DeriveDebug.scala

@@ -0,0 +1,38 @@
+package zio.debug.magnolia
+
+import magnolia1._
+import zio.prelude.Debug
+import zio.prelude.Debug.Repr
+
+import scala.collection.immutable.ListMap
+
+object DeriveDebug {
+
+  type Typeclass[T] = Debug[T]
+
+  def join[T](ctx: CaseClass[Debug, T]): Debug[T] =
+    if (ctx.isValueClass) { (a: T) =>
+      Repr.VConstructor(
+        ctx.typeName.owner.split('.').toList,
+        ctx.typeName.short,
+        ctx.parameters.map(p => p.typeclass.debug(p.dereference(a))).toList
+      )
+    } else if (ctx.isObject) { (_: T) =>
+      Repr.Object(ctx.typeName.owner.split('.').toList, ctx.typeName.short)
+    } else { (a: T) =>
+      Repr.Constructor(
+        ctx.typeName.owner.split('.').toList,
+        ctx.typeName.short,
+        ListMap.apply(ctx.parameters.map(p => p.label -> p.typeclass.debug(p.dereference(a))): _*)
+      )
+    }
+
+  def split[T](ctx: SealedTrait[Debug, T]): Debug[T] =
+    new Debug[T] { self =>
+      def debug(a: T): Repr = ctx.split(a) { sub =>
+        sub.typeclass.debug(sub.cast(a))
+      }
+    }
+
+  def derived[T]: Debug[T] = macro Magnolia.gen[T]
+}

magnolia/shared/src/main/scala-3/zio/debug/magnolia/DeriveDebug.scala

@@ -0,0 +1,40 @@
+package zio.debug.magnolia
+
+import magnolia1._
+// import zio.prelude.Debug
+// import zio.prelude.Debug.Repr
+
+import scala.collection.immutable.ListMap
+import scala.language.experimental.macros
+import zio.prelude.Debug
+import zio.prelude.Debug.Repr
+
+object DeriveDebug extends AutoDerivation[Debug] {
+
+  type Typeclass[T] = Debug[T]
+
+  def join[T](ctx: CaseClass[Debug, T]): Debug[T] =
+    if (ctx.isValueClass) { (a: T) =>
+      Repr.VConstructor(
+        ctx.typeInfo.owner.split('.').toList,
+        ctx.typeInfo.short,
+        ctx.parameters.map(p => p.typeclass.debug(p.deref(a))).toList
+      )
+    } else if (ctx.isObject) { (_: T) =>
+      Repr.Object(ctx.typeInfo.owner.split('.').toList, ctx.typeInfo.short)
+    } else { (a: T) =>
+      Repr.Constructor(
+        ctx.typeInfo.owner.split('.').toList,
+        ctx.typeInfo.short,
+        ListMap.from(ctx.parameters.map(p => p.label -> p.typeclass.debug(p.deref(a))))
+      )
+    }
+
+  def split[T](ctx: SealedTrait[Debug, T]): Debug[T] =
+    new Debug[T] { self =>
+      def debug(a: T): Repr = ctx.choose(a) { sub =>
+        sub.typeclass.debug(sub.cast(a))
+      }
+    }
+
+}

project/BuildHelper.scala

@@ -76,6 +76,17 @@ object BuildHelper {
     Test / parallelExecution := false
   )
 
+  val magnoliaSettings =
+    libraryDependencies += {
+      scalaVersion.value match {
+        case Scala3 =>
+          "com.softwaremill.magnolia1_3" %% "magnolia" % "1.3.7"
+        case _      =>
+          "com.softwaremill.magnolia1_2" %% "magnolia" % "1.1.10"
+//        libraryDependencies += compilerPlugin("org.typelevel" %% "kind-projector" % "0.13.3" cross CrossVersion.full)
+      }
+    }
+
   // Keep this consistent with the version in .core-tests/shared/src/test/scala/REPLSpec.scala
   val replSettings = makeReplSettings {
     """|import zio._