Merge pull request #1841 from adriaanm/rebase-6827-2.10.x

Fix Iterator#copyToArray (fixes SI-6827).

3 files changed, 49 insertions, 2 deletions

diff --git a/src/library/scala/collection/Iterator.scala b/src/library/scala/collection/Iterator.scala
index cbf8cc4931..696bc4ab5c 100644
--- a/src/library/scala/collection/Iterator.scala
+++ b/src/library/scala/collection/Iterator.scala
@@ -1111,9 +1111,10 @@ trait Iterator[+A] extends TraversableOnce[A] {
    *    $willNotTerminateInf
    */
   def copyToArray[B >: A](xs: Array[B], start: Int, len: Int): Unit = {
+    require(start >= 0 && start < xs.length, s"start $start out of range ${xs.length}")
     var i = start
-    val end = start + math.min(len, xs.length)
-    while (hasNext && i < end) {
+    val end = start + math.min(len, xs.length - start)
+    while (i < end && hasNext) {
       xs(i) = next()
       i += 1
     }
diff --git a/test/files/run/t6827.check b/test/files/run/t6827.check
new file mode 100644
index 0000000000..3a3a71c67d
--- /dev/null
+++ b/test/files/run/t6827.check
@@ -0,0 +1,15 @@
+start at -5: java.lang.IllegalArgumentException: requirement failed: start -5 out of range 10
+start at -1: java.lang.IllegalArgumentException: requirement failed: start -1 out of range 10
+start at limit: java.lang.IllegalArgumentException: requirement failed: start 10 out of range 10
+start at limit-1: ok
+first 10: ok
+read all: ok
+test huge len: ok
+5 from 5: ok
+20 from 5: ok
+test len overflow: ok
+start beyond limit: java.lang.IllegalArgumentException: requirement failed: start 30 out of range 10
+read 0: ok
+read -1: ok
+invalid read 0: java.lang.IllegalArgumentException: requirement failed: start 30 out of range 10
+invalid read -1: java.lang.IllegalArgumentException: requirement failed: start 30 out of range 10
diff --git a/test/files/run/t6827.scala b/test/files/run/t6827.scala
new file mode 100644
index 0000000000..7e8918e3dc
--- /dev/null
+++ b/test/files/run/t6827.scala
@@ -0,0 +1,31 @@
+object Test extends App {
+  val ns = (0 until 20)
+  val arr = new Array[Int](10)
+
+  def tryit(label: String, start: Int, len: Int): Unit = {
+    val status = try {
+      val it = ns.toIterator
+      it.copyToArray(arr, start, len)
+      "ok"
+    } catch {
+      case e: Exception => e.toString
+    }
+    println("%s: %s" format (label, status))
+  }
+
+  tryit("start at -5", -5, 10)
+  tryit("start at -1", -1, 10)
+  tryit("start at limit", 10, 10)
+  tryit("start at limit-1", 9, 10)
+  tryit("first 10", 0, 10)
+  tryit("read all", 0, 20)
+  tryit("test huge len", 0, Int.MaxValue)
+  tryit("5 from 5", 5, 10)
+  tryit("20 from 5", 5, 20)
+  tryit("test len overflow", 5, Int.MaxValue)
+  tryit("start beyond limit", 30, 10)
+  tryit("read 0", 0, 0)
+  tryit("read -1", 0, -1)
+  tryit("invalid read 0", 30, 0)
+  tryit("invalid read -1", 30, -1)
+}