Assert if DBClientCursor is NULL SERVER-1372

2 files changed, 11 insertions, 2 deletions

diff --git a/client/dbclientcursor.cpp b/client/dbclientcursor.cpp
index f97919862cd..9fe40f97a70 100644
--- a/client/dbclientcursor.cpp
+++ b/client/dbclientcursor.cpp
@@ -130,6 +130,8 @@ namespace mongo {
 
     /** If true, safe to call next().  Requests more from server if necessary. */
     bool DBClientCursor::more() {
+        _assertIfNull();
+
         if ( !_putBack.empty() )
             return true;
         
@@ -200,6 +202,9 @@ namespace mongo {
     }
 
     DBClientCursor::~DBClientCursor() {
+        if (!this)
+            return;
+
         DESTRUCTOR_GUARD (
 
             if ( cursorId && _ownCursor ) {
diff --git a/client/dbclientcursor.h b/client/dbclientcursor.h
index 84f9cc6cc35..8f941400fe8 100644
--- a/client/dbclientcursor.h
+++ b/client/dbclientcursor.h
@@ -38,7 +38,7 @@ namespace mongo {
             if you want to exhaust whatever data has been fetched to the client already but 
             then perhaps stop.
         */
-        bool moreInCurrentBatch() { return !_putBack.empty() || pos < nReturned; }
+        bool moreInCurrentBatch() { _assertIfNull(); return !_putBack.empty() || pos < nReturned; }
 
         /** next
 		   @return next object in the result cursor.
@@ -90,7 +90,7 @@ namespace mongo {
            available from the dbclientcursor.
         */
         bool isDead() const {
-            return cursorId == 0;
+            return  !this || cursorId == 0;
         }
 
         bool tailable() const {
@@ -102,6 +102,7 @@ namespace mongo {
             ResultFlag_ErrSet is the possible exception to that
         */
         bool hasResultFlag( int flag ){
+            _assertIfNull();
             return (resultFlags & flag) != 0;
         }
 
@@ -176,6 +177,9 @@ namespace mongo {
         void exhaustReceiveMore(); // for exhaust
         bool _ownCursor; // see decouple()
         string _scopedHost;
+
+        // Don't call from a virtual function
+        void _assertIfNull() { uassert(13348, "connection died", this); }
     };