From 07c61394e90bd0b52d582d783944053a4b614fad Mon Sep 17 00:00:00 2001
From: Moxie Marlinspike <moxie@thoughtcrime.org>
Date: Tue, 19 Aug 2014 14:46:01 -0700
Subject: [PATCH] When processing PreKeyBundle, archive current session if it
 exists.

---
 .../java/org/whispersystems/libaxolotl/SessionBuilder.java   | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/libaxolotl/src/main/java/org/whispersystems/libaxolotl/SessionBuilder.java b/libaxolotl/src/main/java/org/whispersystems/libaxolotl/SessionBuilder.java
index be9ed18f3e..bcf0ef962e 100644
--- a/libaxolotl/src/main/java/org/whispersystems/libaxolotl/SessionBuilder.java
+++ b/libaxolotl/src/main/java/org/whispersystems/libaxolotl/SessionBuilder.java
@@ -222,6 +222,7 @@ public class SessionBuilder {
         throw new InvalidKeyException("Both signed and unsigned prekeys are absent!");
       }
 
+      boolean       isExistingSession = sessionStore.containsSession(recipientId, deviceId);
       SessionRecord sessionRecord     = sessionStore.loadSession(recipientId, deviceId);
       ECKeyPair     ourBaseKey        = Curve.generateKeyPair();
       ECPublicKey   theirSignedPreKey = preKey.getSignedPreKey() != null ? preKey.getSignedPreKey() :
@@ -238,8 +239,8 @@ public class SessionBuilder {
                                            Optional.fromNullable(preKey.getPreKey()) :
                                            Optional.<ECPublicKey>absent());
 
-      if (sessionRecord.getSessionState().getNeedsRefresh()) sessionRecord.archiveCurrentState();
-      else                                                   sessionRecord.reset();
+      if (isExistingSession) sessionRecord.archiveCurrentState();
+      else                   sessionRecord.reset();
 
       RatchetingSession.initializeSession(sessionRecord.getSessionState(),
                                           preKey.getSignedPreKey() == null ? 2 : 3,