Fixed REP assert on missing envelope

Signed-off-by: Pieter Hintjens <ph@imatix.com>

src/rep.cpp

@@ -67,24 +67,38 @@ int zmq::rep_t::xrecv (msg_t *msg_, int flags_)
     if (request_begins) {
 
         //  Copy the backtrace stack to the reply pipe.
-        bool bottom = false;
-        while (!bottom) {
+        while (true) {
 
-            //  TODO: What if request can be read but reply pipe is not
-            //  ready for writing?
+            //  TODO: If request can be read but reply pipe is not
+            //  ready for writing, we should drop the reply.
 
             //  Get next part of the backtrace stack.
             int rc = xrep_t::xrecv (msg_, flags_);
             if (rc != 0)
                 return rc;
-            zmq_assert (msg_->flags () & msg_t::more);
+
+            if (msg_->flags () & msg_t::more) {
 
                 //  Empty message part delimits the traceback stack.
-            bottom = (msg_->size () == 0);
+                bool bottom = (msg_->size () == 0);
 
                 //  Push it to the reply pipe.
                 rc = xrep_t::xsend (msg_, flags_);
                 zmq_assert (rc == 0);
+
+                //  The end of the traceback, move to processing message body.
+                if (bottom)
+                    break;
+            }
+            else {
+
+                //  If the traceback stack is malformed, discard anything
+                //  already sent to pipe (we're at end of invalid message)
+                //  and continue reading -- that'll switch us to the next pipe
+                //  and next request.
+                rc = xrep_t::rollback ();
+                zmq_assert (rc == 0);
+            }
         }
 
         request_begins = false;

src/xrep.cpp

@@ -289,6 +289,17 @@ int zmq::xrep_t::xrecv (msg_t *msg_, int flags_)
     return -1;
 }
 
+int zmq::xrep_t::rollback (void)
+{
+    if (current_out) {
+        current_out->rollback ();
+        current_out = NULL;
+        more_out = false;
+    }
+    return 0;
+}
+
+
 bool zmq::xrep_t::xhas_in ()
 {
     //  There are subsequent parts of the partly-read message available.

src/xrep.hpp

@@ -51,6 +51,11 @@ namespace zmq
         bool xhas_in ();
         bool xhas_out ();
 
+    protected:
+
+        //  Rollback any message parts that were sent but not yet flushed.
+        int rollback ();
+
     private:
 
         //  Hook into the termination process.