Making empty streams serializable.

No review.

3 files changed, 27 insertions, 1 deletions

diff --git a/src/library/scala/collection/immutable/Stream.scala b/src/library/scala/collection/immutable/Stream.scala
index a0e5668349..66d1562884 100644
--- a/src/library/scala/collection/immutable/Stream.scala
+++ b/src/library/scala/collection/immutable/Stream.scala
@@ -569,7 +569,7 @@ object Stream extends SeqFactory[Stream] {
     def result: Stream[A] = parts.toStream flatMap (_.toStream)
   }
 
-  object Empty extends Stream[Nothing] {
+  object Empty extends Stream[Nothing] with Serializable {
     override def isEmpty = true
     override def head = throw new NoSuchElementException("head of empty stream")
     override def tail = throw new UnsupportedOperationException("tail of empty stream")
diff --git a/test/files/run/serialize-stream.check b/test/files/run/serialize-stream.check
new file mode 100644
index 0000000000..e2a9f57aa7
--- /dev/null
+++ b/test/files/run/serialize-stream.check
@@ -0,0 +1,6 @@
+Stream(1, ?)
+List(1, 2, 3)
+Stream(1, ?)
+List(1)
+Stream()
+List()
diff --git a/test/files/run/serialize-stream.scala b/test/files/run/serialize-stream.scala
new file mode 100644
index 0000000000..3ab9f2df34
--- /dev/null
+++ b/test/files/run/serialize-stream.scala
@@ -0,0 +1,20 @@
+
+
+object Test {
+  def ser[T](s: Stream[T]) {
+    val bos = new java.io.ByteArrayOutputStream()
+    val oos = new java.io.ObjectOutputStream(bos)
+    oos.writeObject(s)
+
+    val ois = new java.io.ObjectInputStream(new java.io.ByteArrayInputStream(bos.toByteArray))
+    val obj = ois.readObject()
+    println(obj)
+    println(obj.asInstanceOf[Seq[T]].toList)
+  }
+
+  def main(args: Array[String]) {
+    ser(Stream(1, 2, 3))
+    ser(Stream(1))
+    ser(Stream())
+  }
+}