From 9a2486087a9739108265e7830ebaa96373605d02 Mon Sep 17 00:00:00 2001
From: Carsten Varming <cvarming@twitter.com>
Date: Wed, 20 Jul 2016 23:57:35 -0400
Subject: SI-8774 Null link fields in mutable hash maps on removal.

---
 src/library/scala/collection/mutable/HashTable.scala     | 5 ++++-
 src/library/scala/collection/mutable/LinkedHashMap.scala | 2 ++
 src/library/scala/collection/mutable/LinkedHashSet.scala | 2 ++
 3 files changed, 8 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/library/scala/collection/mutable/HashTable.scala b/src/library/scala/collection/mutable/HashTable.scala
index b48a32fa37..bb15788bdf 100644
--- a/src/library/scala/collection/mutable/HashTable.scala
+++ b/src/library/scala/collection/mutable/HashTable.scala
@@ -183,6 +183,7 @@ trait HashTable[A, Entry >: Null <: HashEntry[A, Entry]] extends HashTable.HashU
         table(h) = e.next
         tableSize = tableSize - 1
         nnSizeMapRemove(h)
+        e.next = null
         return e
       } else {
         var e1 = e.next
@@ -194,6 +195,7 @@ trait HashTable[A, Entry >: Null <: HashEntry[A, Entry]] extends HashTable.HashU
           e.next = e1.next
           tableSize = tableSize - 1
           nnSizeMapRemove(h)
+          e1.next = null
           return e1
         }
       }
@@ -227,8 +229,9 @@ trait HashTable[A, Entry >: Null <: HashEntry[A, Entry]] extends HashTable.HashU
     var es        = iterTable(idx)
 
     while (es != null) {
+      val next = es.next // Cache next in case f removes es.
       f(es.asInstanceOf[Entry])
-      es = es.next
+      es = next
 
       while (es == null && idx > 0) {
         idx -= 1
diff --git a/src/library/scala/collection/mutable/LinkedHashMap.scala b/src/library/scala/collection/mutable/LinkedHashMap.scala
index 275f490675..a731b1bbdc 100644
--- a/src/library/scala/collection/mutable/LinkedHashMap.scala
+++ b/src/library/scala/collection/mutable/LinkedHashMap.scala
@@ -81,6 +81,8 @@ class LinkedHashMap[A, B] extends AbstractMap[A, B]
       else e.earlier.later = e.later
       if (e.later eq null) lastEntry = e.earlier
       else e.later.earlier = e.earlier
+      e.earlier = null // Null references to prevent nepotism
+      e.later = null
       Some(e.value)
     }
   }
diff --git a/src/library/scala/collection/mutable/LinkedHashSet.scala b/src/library/scala/collection/mutable/LinkedHashSet.scala
index 756a2f73c1..f00cbd90dc 100644
--- a/src/library/scala/collection/mutable/LinkedHashSet.scala
+++ b/src/library/scala/collection/mutable/LinkedHashSet.scala
@@ -73,6 +73,8 @@ class LinkedHashSet[A] extends AbstractSet[A]
       else e.earlier.later = e.later
       if (e.later eq null) lastEntry = e.earlier
       else e.later.earlier = e.earlier
+      e.earlier = null // Null references to prevent nepotism
+      e.later = null
       true
     }
   }
-- 
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