Fix t6114 - ++ on JList wrapper modifies underlying collection.

We solve this by overriding clone for JListWrapper to actually do a full clone.

Note: This fix may need to be included other places, *but* we're not sure we've cloned the collection sensibly.  I.e.  is ArrayList a good default?

1 files changed, 7 insertions, 0 deletions

diff --git a/src/library/scala/collection/convert/Wrappers.scala b/src/library/scala/collection/convert/Wrappers.scala
index 75707b69b0..7c97972c48 100644
--- a/src/library/scala/collection/convert/Wrappers.scala
+++ b/src/library/scala/collection/convert/Wrappers.scala
@@ -96,6 +96,9 @@ private[collection] trait Wrappers {
     def remove(i: Int) = underlying.remove(i)
     def clear() = underlying.clear()
     def result = this
+    // Note: Clone cannot just call underlying.clone because in Java, only specific collections
+    // expose clone methods.  Generically, they're protected.
+    override def clone(): JListWrapper[A] = JListWrapper(new ju.ArrayList[A](underlying))
   }
 
   class SetWrapper[A](underlying: Set[A]) extends ju.AbstractSet[A] {
@@ -149,6 +152,10 @@ private[collection] trait Wrappers {
     override def clear() = underlying.clear()
 
     override def empty = JSetWrapper(new ju.HashSet[A])
+    // Note: Clone cannot just call underlying.clone because in Java, only specific collections
+    // expose clone methods.  Generically, they're protected.
+    override def clone() =
+      new JSetWrapper[A](new ju.LinkedHashSet[A](underlying))
   }
 
   class MapWrapper[A, B](underlying: Map[A, B]) extends ju.AbstractMap[A, B] { self =>