Merge pull request #5734 from dotty-staging/make-case-class-serializable

Make case classes Serializable

Author: smarter

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -521,7 +521,7 @@ object desugar {
     if (isEnumCase && parents.isEmpty)
       parents1 = enumClassTypeRef :: Nil
     if (isCaseClass | isCaseObject)
-      parents1 = parents1 :+ scalaDot(str.Product.toTypeName)
+      parents1 = parents1 :+ scalaDot(str.Product.toTypeName) :+ scalaDot(nme.Serializable.toTypeName)
     if (isEnum)
       parents1 = parents1 :+ ref(defn.EnumType)
 

compiler/src/dotty/tools/dotc/printing/DecompilerPrinter.scala

@@ -57,7 +57,8 @@ class DecompilerPrinter(_ctx: Context) extends RefinedPrinter(_ctx) {
     def isSynthetic(parent: Tree): Boolean = {
       val sym = parent.symbol
       sym.maybeOwner == defn.ObjectClass ||
-      (sym == defn.ProductClass && impl.symbol.owner.is(Case))
+      (sym == defn.ProductClass && impl.symbol.owner.is(Case)) ||
+      (sym == defn.SerializableClass && impl.symbol.owner.is(Case))
     }
     val parents = impl.parents.filterNot(isSynthetic)
     val body = impl.body.filterNot(_.symbol.is(ParamAccessor))

library/src/scala/tasty/reflect/Printers.scala

@@ -598,6 +598,7 @@ trait Printers
           val parents1 = parents.filter {
             case IsTerm(Term.Apply(Term.Select(Term.New(tpt), _), _)) => !Types.JavaLangObject.unapply(tpt.tpe)
             case IsTypeTree(TypeTree.Select(Term.Select(Term.Ident("_root_"), "scala"), "Product")) => false
+            case IsTypeTree(TypeTree.Select(Term.Select(Term.Ident("_root_"), "scala"), "Serializable")) => false
             case _ => true
           }
           if (parents1.nonEmpty)

tests/neg/typeclass-derivation2.scala

@@ -170,7 +170,7 @@ object Pair {
   }
 }
 
-sealed trait Either[+L, +R] extends Product // derives Eq, Pickler, Show
+sealed trait Either[+L, +R] extends Product with Serializable // derives Eq, Pickler, Show
 case class Left[L](x: L) extends Either[L, Nothing]
 case class Right[R](x: R) extends Either[Nothing, R]
 
@@ -275,4 +275,4 @@ object Test extends App {
     |
     |But no implicit values were found that match type Show[Pair[Int]].
 */
-}
+}

tests/run/case-class-serializable.scala

@@ -0,0 +1,37 @@
+case class Foo(s: String)
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val foo = Foo("bar")
+    assert(foo.isInstanceOf[Serializable])
+    assert(SerDes.serializeDeserialize[Foo](foo) == foo)
+  }
+}
+
+// From https://github.com/scala/scala/pull/5278
+object SerDes {
+  import java.io._
+
+  def assertNotSerializable(a: AnyRef): Unit = {
+    try {
+      serialize(a)
+      assert(false)
+    } catch {
+      case _: NotSerializableException => // okay
+    }
+  }
+
+  def serialize(obj: AnyRef): Array[Byte] = {
+    val buffer = new ByteArrayOutputStream
+    val out = new ObjectOutputStream(buffer)
+    out.writeObject(obj)
+    buffer.toByteArray
+  }
+
+  def deserialize(a: Array[Byte]): AnyRef = {
+    val in = new ObjectInputStream(new ByteArrayInputStream(a))
+    in.readObject
+  }
+
+  def serializeDeserialize[T <: AnyRef](obj: T) = deserialize(serialize(obj)).asInstanceOf[T]
+}

tests/run/tasty-extractors-2.check

@@ -49,7 +49,7 @@ Type.SymRef(IsClassSymbol(<scala.Unit>), Type.ThisType(Type.SymRef(IsPackageSymb
 Term.Inlined(None, Nil, Term.Block(List(ClassDef("Foo", DefDef("<init>", Nil, List(Nil), TypeTree.Inferred(), None), List(Term.Apply(Term.Select(Term.New(TypeTree.Inferred()), "<init>"), Nil)), Nil, None, List(DefDef("a", Nil, Nil, TypeTree.Inferred(), Some(Term.Literal(Constant.Int(0))))))), Term.Literal(Constant.Unit())))
 Type.SymRef(IsClassSymbol(<scala.Unit>), Type.ThisType(Type.SymRef(IsPackageSymbol(<scala>), NoPrefix())))
 
-Term.Inlined(None, Nil, Term.Block(List(ClassDef("Foo", DefDef("<init>", Nil, List(Nil), TypeTree.Inferred(), None), List(Term.Apply(Term.Select(Term.New(TypeTree.Inferred()), "<init>"), Nil), TypeTree.Select(Term.Select(Term.Ident("_root_"), "scala"), "Product")), Nil, None, List(DefDef("productElementName", Nil, List(List(ValDef("x$1", TypeTree.Select(Term.Select(Term.Ident("_root_"), "scala"), "Int"), None))), TypeTree.Select(Term.Select(Term.Ident("java"), "lang"), "String"), Some(Term.Match(Term.Ident("x$1"), List(CaseDef(Pattern.Value(Term.Ident("_")), None, Term.Apply(Term.Ident("throw"), List(Term.Apply(Term.Select(Term.New(TypeTree.Select(Term.Select(Term.Ident("java"), "lang"), "IndexOutOfBoundsException")), "<init>"), List(Term.Apply(Term.Select(Term.Select(Term.Select(Term.Ident("java"), "lang"), "String"), "valueOf"), List(Term.Ident("x$1")))))))))))), DefDef("copy", Nil, List(Nil), TypeTree.Inferred(), Some(Term.Apply(Term.Select(Term.New(TypeTree.Inferred()), "<init>"), Nil))), DefDef("hashCode", Nil, List(Nil), TypeTree.Inferred(), Some(Term.Literal(Constant.Int(394005536)))), DefDef("equals", Nil, List(List(ValDef("x$0", TypeTree.Inferred(), None))), TypeTree.Inferred(), Some(Term.Apply(Term.Select(Term.Apply(Term.Select(Term.This(Some(Id("Foo"))), "eq"), List(Term.TypeApply(Term.Select(Term.Ident("x$0"), "asInstanceOf"), List(TypeTree.Inferred())))), "||"), List(Term.Match(Term.Ident("x$0"), List(CaseDef(Pattern.Bind("x$0", Pattern.TypeTest(TypeTree.Inferred())), None, Term.Literal(Constant.Boolean(true))), CaseDef(Pattern.Value(Term.Ident("_")), None, Term.Literal(Constant.Boolean(false))))))))), DefDef("toString", Nil, List(Nil), TypeTree.Inferred(), Some(Term.Apply(Term.Ident("_toString"), List(Term.This(Some(Id("Foo"))))))), DefDef("canEqual", Nil, List(List(ValDef("that", TypeTree.Inferred(), None))), TypeTree.Inferred(), Some(Term.TypeApply(Term.Select(Term.Ident("that"), "isInstanceOf"), List(TypeTree.Inferred())))), DefDef("productArity", Nil, Nil, TypeTree.Inferred(), Some(Term.Literal(Constant.Int(0)))), DefDef("productPrefix", Nil, Nil, TypeTree.Inferred(), Some(Term.Literal(Constant.String("Foo")))), DefDef("productElement", Nil, List(List(ValDef("n", TypeTree.Inferred(), None))), TypeTree.Inferred(), Some(Term.Match(Term.Ident("n"), List(CaseDef(Pattern.Value(Term.Ident("_")), None, Term.Apply(Term.Ident("throw"), List(Term.Apply(Term.Select(Term.New(TypeTree.Inferred()), "<init>"), List(Term.Apply(Term.Select(Term.Ident("n"), "toString"), Nil)))))))))))), ValDef("Foo", TypeTree.Ident("Foo$"), Some(Term.Apply(Term.Select(Term.New(TypeTree.Ident("Foo$")), "<init>"), Nil))), ClassDef("Foo$", DefDef("<init>", Nil, List(Nil), TypeTree.Inferred(), None), List(Term.Apply(Term.Select(Term.New(TypeTree.Inferred()), "<init>"), Nil), TypeTree.Applied(TypeTree.Inferred(), List(TypeTree.Inferred()))), Nil, Some(ValDef("_", TypeTree.Singleton(Term.Ident("Foo")), None)), List(DefDef("apply", Nil, List(Nil), TypeTree.Inferred(), Some(Term.Apply(Term.Select(Term.New(TypeTree.Inferred()), "<init>"), Nil))), DefDef("unapply", Nil, List(List(ValDef("x$1", TypeTree.Inferred(), None))), TypeTree.Inferred(), Some(Term.Literal(Constant.Boolean(true))))))), Term.Literal(Constant.Unit())))
+Term.Inlined(None, Nil, Term.Block(List(ClassDef("Foo", DefDef("<init>", Nil, List(Nil), TypeTree.Inferred(), None), List(Term.Apply(Term.Select(Term.New(TypeTree.Inferred()), "<init>"), Nil), TypeTree.Select(Term.Select(Term.Ident("_root_"), "scala"), "Product"), TypeTree.Select(Term.Select(Term.Ident("_root_"), "scala"), "Serializable")), Nil, None, List(DefDef("productElementName", Nil, List(List(ValDef("x$1", TypeTree.Select(Term.Select(Term.Ident("_root_"), "scala"), "Int"), None))), TypeTree.Select(Term.Select(Term.Ident("java"), "lang"), "String"), Some(Term.Match(Term.Ident("x$1"), List(CaseDef(Pattern.Value(Term.Ident("_")), None, Term.Apply(Term.Ident("throw"), List(Term.Apply(Term.Select(Term.New(TypeTree.Select(Term.Select(Term.Ident("java"), "lang"), "IndexOutOfBoundsException")), "<init>"), List(Term.Apply(Term.Select(Term.Select(Term.Select(Term.Ident("java"), "lang"), "String"), "valueOf"), List(Term.Ident("x$1")))))))))))), DefDef("copy", Nil, List(Nil), TypeTree.Inferred(), Some(Term.Apply(Term.Select(Term.New(TypeTree.Inferred()), "<init>"), Nil))), DefDef("hashCode", Nil, List(Nil), TypeTree.Inferred(), Some(Term.Literal(Constant.Int(394005536)))), DefDef("equals", Nil, List(List(ValDef("x$0", TypeTree.Inferred(), None))), TypeTree.Inferred(), Some(Term.Apply(Term.Select(Term.Apply(Term.Select(Term.This(Some(Id("Foo"))), "eq"), List(Term.TypeApply(Term.Select(Term.Ident("x$0"), "asInstanceOf"), List(TypeTree.Inferred())))), "||"), List(Term.Match(Term.Ident("x$0"), List(CaseDef(Pattern.Bind("x$0", Pattern.TypeTest(TypeTree.Inferred())), None, Term.Literal(Constant.Boolean(true))), CaseDef(Pattern.Value(Term.Ident("_")), None, Term.Literal(Constant.Boolean(false))))))))), DefDef("toString", Nil, List(Nil), TypeTree.Inferred(), Some(Term.Apply(Term.Ident("_toString"), List(Term.This(Some(Id("Foo"))))))), DefDef("canEqual", Nil, List(List(ValDef("that", TypeTree.Inferred(), None))), TypeTree.Inferred(), Some(Term.TypeApply(Term.Select(Term.Ident("that"), "isInstanceOf"), List(TypeTree.Inferred())))), DefDef("productArity", Nil, Nil, TypeTree.Inferred(), Some(Term.Literal(Constant.Int(0)))), DefDef("productPrefix", Nil, Nil, TypeTree.Inferred(), Some(Term.Literal(Constant.String("Foo")))), DefDef("productElement", Nil, List(List(ValDef("n", TypeTree.Inferred(), None))), TypeTree.Inferred(), Some(Term.Match(Term.Ident("n"), List(CaseDef(Pattern.Value(Term.Ident("_")), None, Term.Apply(Term.Ident("throw"), List(Term.Apply(Term.Select(Term.New(TypeTree.Inferred()), "<init>"), List(Term.Apply(Term.Select(Term.Ident("n"), "toString"), Nil)))))))))))), ValDef("Foo", TypeTree.Ident("Foo$"), Some(Term.Apply(Term.Select(Term.New(TypeTree.Ident("Foo$")), "<init>"), Nil))), ClassDef("Foo$", DefDef("<init>", Nil, List(Nil), TypeTree.Inferred(), None), List(Term.Apply(Term.Select(Term.New(TypeTree.Inferred()), "<init>"), Nil), TypeTree.Applied(TypeTree.Inferred(), List(TypeTree.Inferred()))), Nil, Some(ValDef("_", TypeTree.Singleton(Term.Ident("Foo")), None)), List(DefDef("apply", Nil, List(Nil), TypeTree.Inferred(), Some(Term.Apply(Term.Select(Term.New(TypeTree.Inferred()), "<init>"), Nil))), DefDef("unapply", Nil, List(List(ValDef("x$1", TypeTree.Inferred(), None))), TypeTree.Inferred(), Some(Term.Literal(Constant.Boolean(true))))))), Term.Literal(Constant.Unit())))
 Type.SymRef(IsClassSymbol(<scala.Unit>), Type.ThisType(Type.SymRef(IsPackageSymbol(<scala>), NoPrefix())))
 
 Term.Inlined(None, Nil, Term.Block(List(ClassDef("Foo1", DefDef("<init>", Nil, List(List(ValDef("a", TypeTree.Ident("Int"), None))), TypeTree.Inferred(), None), List(Term.Apply(Term.Select(Term.New(TypeTree.Inferred()), "<init>"), Nil)), Nil, None, List(ValDef("a", TypeTree.Inferred(), None)))), Term.Literal(Constant.Unit())))

tests/run/typeclass-derivation2.scala

@@ -179,7 +179,7 @@ object Pair {
   implicit def derived$Show[T: Show]: Show[Pair[T]] = Show.derived
 }
 
-sealed trait Either[+L, +R] extends Product // derives Eq, Pickler, Show
+sealed trait Either[+L, +R] extends Product with Serializable // derives Eq, Pickler, Show
 case class Left[L](x: L) extends Either[L, Nothing]
 case class Right[R](x: R) extends Either[Nothing, R]
 
@@ -486,4 +486,4 @@ object Test extends App {
   val zs1 = copy(zs)
   showPrintln(zs1)
   assert(eql(zs, zs1))
-}
+}

tests/run/typeclass-derivation2a.scala

@@ -179,7 +179,7 @@ object Pair {
   implicit def derived$Show[T: Show]: Show[Pair[T]] = Show.derived
 }
 
-sealed trait Either[+L, +R] extends Product // derives Eq, Pickler, Show
+sealed trait Either[+L, +R] extends Product with Serializable // derives Eq, Pickler, Show
 case class Left[L](x: L) extends Either[L, Nothing]
 case class Right[R](x: R) extends Either[Nothing, R]
 

tests/run/typeclass-derivation3.scala

@@ -16,7 +16,7 @@ object datatypes {
   case class Pair[T](x: T, y: T) derives Eq, Pickler, Show
 
   // another ADT
-  sealed trait Either[+L, +R] extends Product derives Eq, Pickler, Show
+  sealed trait Either[+L, +R] extends Product with Serializable derives Eq, Pickler, Show
   case class Left[L](x: L) extends Either[L, Nothing]
   case class Right[R](x: R) extends Either[Nothing, R]
 }
@@ -311,4 +311,4 @@ object Test extends App {
   val zss1 = pklList.unpickle(buf)
   assert(eql(zss, zss1))
   showPrintln(zss1)
-}
+}