Problem: inconsistent _out_pipes when using the same routing id without ZMQ_ROUTER_HANDOVER

Solution: added test case, do not erase existing without ZMQ_ROUTER_HANDOVER

src/router.cpp

@@ -198,7 +198,7 @@ int zmq::router_t::xsend (msg_t *msg_)
 
             //  Find the pipe associated with the routing id stored in the prefix.
             //  If there's no such pipe just silently ignore the message, unless
-            //  router_mandatory is set.            ;
+            //  router_mandatory is set.
             out_pipe_t *out_pipe = lookup_out_pipe (
               blob_t (static_cast<unsigned char *> (msg_->data ()),
                       msg_->size (), zmq::reference_tag_t ()));
@@ -487,9 +487,9 @@ bool zmq::router_t::identify_peer (pipe_t *pipe_, bool locally_initiated_)
 
             //  Try to remove an existing routing id entry to allow the new
             //  connection to take the routing id.
-            out_pipe_t existing_outpipe = try_erase_out_pipe (routing_id);
+            out_pipe_t *existing_outpipe = lookup_out_pipe (routing_id);
 
-            if (existing_outpipe.pipe) {
+            if (existing_outpipe) {
                 if (!_handover)
                     //  Ignore peers with duplicate ID
                     return false;
@@ -502,15 +502,16 @@ bool zmq::router_t::identify_peer (pipe_t *pipe_, bool locally_initiated_)
                 put_uint32 (buf + 1, _next_integral_routing_id++);
                 blob_t new_routing_id (buf, sizeof buf);
 
-                existing_outpipe.pipe->set_router_socket_routing_id (
-                  new_routing_id);
+                pipe_t *const old_pipe = existing_outpipe->pipe;
 
-                add_out_pipe (ZMQ_MOVE (new_routing_id), existing_outpipe.pipe);
+                erase_out_pipe (old_pipe);
+                old_pipe->set_router_socket_routing_id (new_routing_id);
+                add_out_pipe (ZMQ_MOVE (new_routing_id), old_pipe);
 
-                if (existing_outpipe.pipe == _current_in)
+                if (old_pipe == _current_in)
                     _terminate_current_in = true;
                 else
-                    existing_outpipe.pipe->terminate (true);
+                    old_pipe->terminate (true);
             }
         }
     }

tests/test_router_handover.cpp

@@ -43,7 +43,7 @@ void tearDown ()
     teardown_test_context ();
 }
 
-void test_x ()
+void test_with_handover ()
 {
     size_t len = MAX_SOCKET_STRING;
     char my_endpoint[MAX_SOCKET_STRING];
@@ -85,15 +85,16 @@ void test_x ()
     recv_string_expect_success (router, "Hello", 0);
 
     //  Send a message to 'X' routing id. This should be delivered
-    //  to the second dealer, instead of the first beccause of the handover.
+    //  to the second dealer, instead of the first because of the handover.
     send_string_expect_success (router, "X", ZMQ_SNDMORE);
     send_string_expect_success (router, "Hello", 0);
 
     //  Ensure that the first dealer doesn't receive the message
     //  but the second one does
-    int rc = zmq_recv (dealer_one, buffer, 255, ZMQ_NOBLOCK);
-    TEST_ASSERT_EQUAL_INT (-1, rc);
-    TEST_ASSERT_EQUAL_INT (EAGAIN, errno);
+    const int timeout = SETTLE_TIME;
+    TEST_ASSERT_SUCCESS_ERRNO (
+      zmq_setsockopt (dealer_one, ZMQ_RCVTIMEO, &timeout, sizeof timeout));
+    TEST_ASSERT_FAILURE_ERRNO (EAGAIN, zmq_recv (dealer_one, buffer, 255, 0));
 
     recv_string_expect_success (dealer_two, "Hello", 0);
 
@@ -102,11 +103,69 @@ void test_x ()
     test_context_socket_close (dealer_two);
 }
 
-int main (void)
+void test_without_handover ()
+{
+    size_t len = MAX_SOCKET_STRING;
+    char my_endpoint[MAX_SOCKET_STRING];
+    void *router = test_context_socket (ZMQ_ROUTER);
+
+    TEST_ASSERT_SUCCESS_ERRNO (zmq_bind (router, "tcp://127.0.0.1:*"));
+
+    TEST_ASSERT_SUCCESS_ERRNO (
+      zmq_getsockopt (router, ZMQ_LAST_ENDPOINT, my_endpoint, &len));
+
+    //  Create dealer called "X" and connect it to our router
+    void *dealer_one = test_context_socket (ZMQ_DEALER);
+    TEST_ASSERT_SUCCESS_ERRNO (
+      zmq_setsockopt (dealer_one, ZMQ_ROUTING_ID, "X", 1));
+    TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (dealer_one, my_endpoint));
+
+    //  Get message from dealer to know when connection is ready
+    char buffer[255];
+    send_string_expect_success (dealer_one, "Hello", 0);
+
+    recv_string_expect_success (router, "X", 0);
+    recv_string_expect_success (router, "Hello", 0);
+
+    // Now create a second dealer that uses the same routing id
+    void *dealer_two = test_context_socket (ZMQ_DEALER);
+    TEST_ASSERT_SUCCESS_ERRNO (
+      zmq_setsockopt (dealer_two, ZMQ_ROUTING_ID, "X", 1));
+    TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (dealer_two, my_endpoint));
+
+    //  Send message from second dealer
+    send_string_expect_success (dealer_two, "Hello", 0);
+
+    //  This should be ignored by the router
+    const int timeout = SETTLE_TIME;
+    TEST_ASSERT_SUCCESS_ERRNO (
+      zmq_setsockopt (router, ZMQ_RCVTIMEO, &timeout, sizeof timeout));
+    TEST_ASSERT_FAILURE_ERRNO (EAGAIN, zmq_recv (router, buffer, 255, 0));
+
+    //  Send a message to 'X' routing id. This should be delivered
+    //  to the second dealer, instead of the first because of the handover.
+    send_string_expect_success (router, "X", ZMQ_SNDMORE);
+    send_string_expect_success (router, "Hello", 0);
+
+    //  Ensure that the second dealer doesn't receive the message
+    //  but the first one does
+    TEST_ASSERT_SUCCESS_ERRNO (
+      zmq_setsockopt (dealer_two, ZMQ_RCVTIMEO, &timeout, sizeof timeout));
+    TEST_ASSERT_FAILURE_ERRNO (EAGAIN, zmq_recv (dealer_two, buffer, 255, 0));
+
+    recv_string_expect_success (dealer_one, "Hello", 0);
+
+    test_context_socket_close (router);
+    test_context_socket_close (dealer_one);
+    test_context_socket_close (dealer_two);
+}
+
+int main ()
 {
     setup_test_environment ();
 
     UNITY_BEGIN ();
-    RUN_TEST (test_x);
+    RUN_TEST (test_with_handover);
+    RUN_TEST (test_without_handover);
     return UNITY_END ();
 }