SI-9497 Fix SetLike#clear() default implementation

When dealing with mutable collections, it is not safe to assume iterators will remain consistent when the collection is modified mid-traversal. The bug reported in SI-9497 is very similar to SI-7269, "ConcurrentModificationException when filtering converted Java HashMap". Then, only the `retain` method was fixed. This commit fixes `clear`, which had the same problem.

1 files changed, 26 insertions, 0 deletions

diff --git a/test/junit/scala/collection/mutable/SetLikeTest.scala b/test/junit/scala/collection/mutable/SetLikeTest.scala
new file mode 100644
index 0000000000..c819024558
--- /dev/null
+++ b/test/junit/scala/collection/mutable/SetLikeTest.scala
@@ -0,0 +1,26 @@
+package scala.collection.mutable
+
+import org.junit.Assert._
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+@RunWith(classOf[JUnit4])
+class SetLikeTest {
+
+  class MySet(self: Set[String]) extends Set[String] with SetLike[String, MySet] {
+    override def -=(elem: String) = { self -= elem; this }
+    override def +=(elem: String) = { self += elem; this }
+
+    override def empty = new MySet(self.empty)
+    override def iterator = self.iterator
+    override def contains(elem: String) = self.contains(elem)
+  }
+
+  @Test
+  def hasCorrectClear() {
+    val s = new MySet(Set("EXPOSEDNODE", "CONNECTABLE"))
+    s.clear()
+    assertEquals(new MySet(Set()), s)
+  }
+}