4 files changed, 41 insertions, 3 deletions
diff --git a/autotests/testolmsession.cpp b/autotests/testolmsession.cpp
index fc151621..77ba35ef 100644
--- a/autotests/testolmsession.cpp
+++ b/autotests/testolmsession.cpp
@@ -58,4 +58,30 @@ void TestOlmSession::olmEncryptDecrypt()
 #endif
 }
 
+void TestOlmSession::correctSessionOrdering()
+{
+#ifdef Quotient_E2EE_ENABLED
+    // n0W5IJ2ZmaI9FxKRj/wohUQ6WEU0SfoKsgKKHsr4VbM
+    auto session1 = std::get<std::unique_ptr<QOlmSession>>(QOlmSession::unpickle("7g5cfQRsDk2ROXf9S01n2leZiFRon+EbvXcMOADU0UGvlaV6t/0ihD2/0QGckDIvbmE1aV+PxB0zUtHXh99bI/60N+PWkCLA84jEY4sz3d45ui/TVoFGLDHlymKxvlj7XngXrbtlxSkVntsPzDiNpKEXCa26N2ubKpQ0fbjrV5gbBTYWfU04DXHPXFDTksxpNALYt/h0eVMVhf6hB0ZzpLBsOG0mpwkLufwub0CuDEDGGmRddz3TcNCLq5NnI8R9udDWvHAkTS1UTbHuIf/y6cZg875nJyXpAvd8/XhL8TOo8ot2sE1fElBa4vrH/m9rBQMC1GPkhLBIizmY44C+Sq9PQRnF+uCZ", Unencrypted{}));
+    // +9pHJhP3K4E5/2m8PYBPLh8pS9CJodwUOh8yz3mnmw0
+    auto session2 = std::get<std::unique_ptr<QOlmSession>>(QOlmSession::unpickle("7g5cfQRsDk2ROXf9S01n2leZiFRon+EbvXcMOADU0UFD+q37/WlfTAzQsSjCdD07FcErZ4siEy5vpiB+pyO8i53ptZvb2qRvqNKFzPaXuu33PS2PBTmmnR+kJt+DgDNqWadyaj/WqEAejc7ALqSs5GuhbZtpoLe+lRSRK0rwVX3gzz4qrl8pm0pD5pSZAUWRXDRlieGWMclz68VUvnSaQH7ElTo4S634CJk+xQfFFCD26v0yONPSN6rwouS1cWPuG5jTlnV8vCFVTU2+lduKh54Ko6FUJ/ei4xR8Nk2duBGSc/TdllX9e2lDYHSUkWoD4ti5xsFioB8Blus7JK9BZfcmRmdlxIOD", Unencrypted {}));
+    // MC7n8hX1l7WlC2/WJGHZinMocgiBZa4vwGAOredb/ME
+    auto session3 = std::get<std::unique_ptr<QOlmSession>>(QOlmSession::unpickle("7g5cfQRsDk2ROXf9S01n2leZiFRon+EbvXcMOADU0UGNk2TmVDJ95K0Nywf24FNklNVtXtFDiFPHFwNSmCbHNCp3hsGtZlt0AHUkMmL48XklLqzwtVk5/v2RRmSKR5LqYdIakrtuK/fY0ENhBZIbI1sRetaJ2KMbY9l6rCJNfFg8VhpZ4KTVvEZVuP9g/eZkCnP5NxzXiBRF6nfY3O/zhcKxa3acIqs6BMhyLsfuJ80t+hQ1HvVyuhBerGujdSDzV9tJ9SPidOwfYATk81LVF9hTmnI0KaZa7qCtFzhG0dU/Z3hIWH9HOaw1aSB/IPmughbwdJOwERyhuo3YHoznlQnJ7X252BlI", Unencrypted{}));
+
+    const auto session1Id = session1->sessionId();
+    const auto session2Id = session2->sessionId();
+    const auto session3Id = session3->sessionId();
+
+    std::vector<std::unique_ptr<QOlmSession>> sessionList;
+    sessionList.push_back(std::move(session1));
+    sessionList.push_back(std::move(session2));
+    sessionList.push_back(std::move(session3));
+
+    std::sort(sessionList.begin(), sessionList.end());
+    QCOMPARE(sessionList[0]->sessionId(), session2Id);
+    QCOMPARE(sessionList[1]->sessionId(), session3Id);
+    QCOMPARE(sessionList[2]->sessionId(), session1Id);
+#endif
+}
+
 QTEST_MAIN(TestOlmSession)
diff --git a/autotests/testolmsession.h b/autotests/testolmsession.h
index 49e8c3e3..c03b7b6a 100644
--- a/autotests/testolmsession.h
+++ b/autotests/testolmsession.h
@@ -11,5 +11,6 @@ class TestOlmSession : public QObject
 private Q_SLOTS:
     void olmOutboundSessionCreation();
     void olmEncryptDecrypt();
+    void correctSessionOrdering();
 };
 #endif
diff --git a/lib/olm/session.cpp b/lib/olm/session.cpp
index a05e0786..94f12db6 100644
--- a/lib/olm/session.cpp
+++ b/lib/olm/session.cpp
@@ -108,13 +108,13 @@ std::variant<QByteArray, OlmError> QOlmSession::pickle(const PicklingMode &mode)
     return pickledBuf;
 }
 
-std::variant<std::unique_ptr<QOlmSession>, OlmError> QOlmSession::unpickle(QByteArray &pickled, const PicklingMode &mode)
+std::variant<std::unique_ptr<QOlmSession>, OlmError> QOlmSession::unpickle(const QByteArray &pickled, const PicklingMode &mode)
 {
     QByteArray pickledBuf = pickled;
     auto *olmSession = create();
     QByteArray key = toKey(mode);
     const auto error = olm_unpickle_session(olmSession, key.data(), key.length(),
-            pickled.data(), pickled.length());
+            pickledBuf.data(), pickledBuf.length());
     if (error == olm_error()) {
         return lastError(olmSession);
     }
diff --git a/lib/olm/session.h b/lib/olm/session.h
index 3f1622c7..03b3514e 100644
--- a/lib/olm/session.h
+++ b/lib/olm/session.h
@@ -9,6 +9,7 @@
 #include "olm/e2ee.h"
 #include "olm/message.h"
 #include "olm/errors.h"
+#include <QDebug>
 #include "olm/qolmaccount.h"
 
 namespace Quotient {
@@ -29,7 +30,7 @@ public:
     //! Serialises an `QOlmSession` to encrypted Base64.
     std::variant<QByteArray, OlmError> pickle(const PicklingMode &mode);
     //! Deserialises from encrypted Base64 that was previously obtained by pickling a `QOlmSession`.
-    static std::variant<std::unique_ptr<QOlmSession>, OlmError> unpickle(QByteArray &pickled, const PicklingMode &mode);
+    static std::variant<std::unique_ptr<QOlmSession>, OlmError> unpickle(const QByteArray &pickled, const PicklingMode &mode);
     //! Encrypts a plaintext message using the session.
     Message encrypt(const QString &plaintext);
 
@@ -50,6 +51,15 @@ public:
     //! Checks if the 'prekey' message is for this in-bound session.
     std::variant<bool, OlmError> matchesInboundSession(Message &preKeyMessage);
 
+    friend bool operator<(const QOlmSession& lhs, const QOlmSession& rhs)
+    {
+        return lhs.sessionId() < rhs.sessionId();
+    }
+
+    friend bool operator<(const std::unique_ptr<QOlmSession> &lhs, const std::unique_ptr<QOlmSession> &rhs) {
+        return *lhs < *rhs;
+    }
+
     QOlmSession(OlmSession* session);
 private:
     //! Helper function for creating new sessions and handling errors.
@@ -58,6 +68,7 @@ private:
     OlmSession* m_session;
 };
 
+
 //using QOlmSessionPtr = std::unique_ptr<QOlmSession>;
 
 } //namespace Quotient