3 files changed, 38 insertions, 4 deletions
diff --git a/src/library/scala/collection/mutable/AnyRefMap.scala b/src/library/scala/collection/mutable/AnyRefMap.scala
index df74bb5187..29c92a111c 100644
--- a/src/library/scala/collection/mutable/AnyRefMap.scala
+++ b/src/library/scala/collection/mutable/AnyRefMap.scala
@@ -129,9 +129,20 @@ extends AbstractMap[K, V]
   
   override def getOrElseUpdate(key: K, defaultValue: => V): V = {
     val h = hashOf(key)
-    val i = seekEntryOrOpen(h, key)
+    var i = seekEntryOrOpen(h, key)
     if (i < 0) {
-      val value = defaultValue
+      // It is possible that the default value computation was side-effecting
+      // Our hash table may have resized or even contain what we want now
+      // (but if it does, we'll replace it)
+      val value = {
+        val oh = _hashes
+        val ans = defaultValue
+        if (oh ne _hashes) {
+          i = seekEntryOrOpen(h, key)
+          if (i >= 0) _size -= 1
+        }
+        ans
+      }
       _size += 1
       val j = i & IndexMask
       _hashes(j) = h
diff --git a/src/library/scala/collection/mutable/LongMap.scala b/src/library/scala/collection/mutable/LongMap.scala
index 81c381279f..984ae6f7cc 100644
--- a/src/library/scala/collection/mutable/LongMap.scala
+++ b/src/library/scala/collection/mutable/LongMap.scala
@@ -160,9 +160,20 @@ extends AbstractMap[Long, V]
       else minValue.asInstanceOf[V]
     }
     else {
-      val i = seekEntryOrOpen(key)
+      var i = seekEntryOrOpen(key)
       if (i < 0) {
-        val value = defaultValue
+        // It is possible that the default value computation was side-effecting
+        // Our hash table may have resized or even contain what we want now
+        // (but if it does, we'll replace it)
+        val value = {
+          val ok = _keys
+          val ans = defaultValue
+          if (ok ne _keys) {
+            i = seekEntryOrOpen(key)
+            if (i >= 0) _size -= 1
+          }
+          ans
+        }
         _size += 1
         val j = i & IndexMask
         _keys(j) = key
diff --git a/test/junit/scala/collection/SetMapConsistencyTest.scala b/test/junit/scala/collection/SetMapConsistencyTest.scala
index c62b074483..7bb8ca958b 100644
--- a/test/junit/scala/collection/SetMapConsistencyTest.scala
+++ b/test/junit/scala/collection/SetMapConsistencyTest.scala
@@ -476,4 +476,16 @@ class SetMapConsistencyTest {
     }
     assert(test)
   }
+  
+  @Test
+  def si8213() {
+    val am = new scala.collection.mutable.AnyRefMap[String, Int]
+    for (i <- 0 until 1024) am += i.toString -> i
+    am.getOrElseUpdate("1024", { am.clear; -1 })
+    assert(am == scala.collection.mutable.AnyRefMap("1024" -> -1))
+    val lm = new scala.collection.mutable.LongMap[Int]
+    for (i <- 0 until 1024) lm += i.toLong -> i
+    lm.getOrElseUpdate(1024, { lm.clear; -1 })
+    assert(lm == scala.collection.mutable.LongMap(1024L -> -1))
+  }
 }