Merge pull request #4530 from som-snytt/issue/9332

SI-9332 Iterator.span exhausts leading iterator

1 files changed, 10 insertions, 0 deletions

diff --git a/test/junit/scala/collection/IteratorTest.scala b/test/junit/scala/collection/IteratorTest.scala
index d5389afd0c..1c1e50aed9 100644
--- a/test/junit/scala/collection/IteratorTest.scala
+++ b/test/junit/scala/collection/IteratorTest.scala
@@ -154,4 +154,14 @@ class IteratorTest {
     results += (Stream from 1).toIterator.drop(10).toStream.drop(10).toIterator.next()
     assertSameElements(List(1,1,21), results)
   }
+  // SI-9332
+  @Test def spanExhaustsLeadingIterator(): Unit = {
+    def it = Iterator.iterate(0)(_ + 1).take(6)
+    val (x, y) = it.span(_ != 1)
+    val z = x.toList
+    assertEquals(1, z.size)
+    assertFalse(x.hasNext)
+    assertEquals(1, y.next)
+    assertFalse(x.hasNext)   // was true, after advancing underlying iterator
+  }
 }