Studio publisher does not connect to C++ subscriber (ROS1 live connection)

When publishing messages via Studio, python subscribers can receive the messages no problem. But a subscriber written using C++ does not receive messages.

• Version: Studio 1.4.0
• OS: Ubuntu (but i don’t think this matters)
• ROS 1, live connection, all on one host

Steps To Reproduce

1. Create a simple ROS subscriber in C++
   • I just used the one from the ROS tutorials: Writing the Subscriber Node
   • Any time it receives a message on /chatter, it writes it as a WARN message to the log
2. Launch the subscriber node
3. Verify the subscriber works – run rostopic pub /chatter std_msgs/String "data: 'hi from rostopic pub'" and check that the message shows up in the log
4. Launch Studio
5. Attempt to send a message via Studio

Expected Behavior

• The message is received by the C++ subscriber, and shows up in the log.

Actual Behavior

• No message is received
• There is an error in the node log: Failed to contact publisher [hostname:43047] for topic [/chatter] – this is the foxglove studio publisher

Screenshots and logs

Full node log:

1648577826.702250150  Node Startup
1648577826.710711478 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/subscription.cpp:244(Subscription::pubUpdate)] [topics: /rosout] Publisher update for [/chatter]:  already have these connections: 
1648577826.930959538 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/transport/transport_tcp.cpp:645(TransportTCPPtr ros::TransportTCP::accept)] [topics: /rosout] Accepted connection on socket [7], new socket [11]
1648577826.931075062 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/transport/transport_tcp.cpp:142(TransportTCP::initializeSocket)] [topics: /rosout] Adding tcp socket [11] to pollset
1648577826.931091639 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/connection_manager.cpp:188(ConnectionManager::tcprosAcceptConnection)] [topics: /rosout] TCPROS received a connection from [127.0.0.1:57050]
1648577826.931134390 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/connection_manager.cpp:203(ConnectionManager::onConnectionHeaderReceived)] [topics: /rosout] Connection: Creating TransportSubscriberLink for topic [/rosout] connected to [callerid=[/rosout] address=[TCPROS connection on port 45159 to [127.0.0.1:57050 on socket 11]]]
1648577829.534235544 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/topic_manager.cpp:561(TopicManager::pubUpdate)] [topics: /rosout] Received update for topic [/chatter] (1 publishers)
1648577829.534251940 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/subscription.cpp:244(Subscription::pubUpdate)] [topics: /rosout] Publisher update for [/chatter]: http://mimir:44265/,  already have these connections: 
1648577829.534336646 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/subscription.cpp:421(Subscription::negotiateConnection)] [topics: /rosout] Began asynchronous xmlrpc connection to [mimir:44265]
1648577829.734995483 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/subscription.cpp:509(Subscription::pendingConnectionDone)] [topics: /rosout] Connecting via tcpros to topic [/chatter] at host [mimir:35493]
1648577829.735163047 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/transport/transport_tcp.cpp:326(TransportTCP::connect)] [topics: /rosout] Resolved publisher host [mimir] to [127.0.1.1] for socket [13]
1648577829.735217721 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/transport/transport_tcp.cpp:142(TransportTCP::initializeSocket)] [topics: /rosout] Adding tcp socket [13] to pollset
1648577829.735234714 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/transport/transport_tcp.cpp:365(TransportTCP::connect)] [topics: /rosout] Async connect() in progress to [mimir:35493] on socket [13]
1648577829.735284236 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/subscription.cpp:525(Subscription::pendingConnectionDone)] [topics: /rosout] Connected to publisher of topic [/chatter] at [mimir:35493]
1648577829.736062366 WARN /chatter_listener [/home/jessica/dev/personal/ros_tutorials/catkin_ws/src/beginner_tutorials/src/listener.cpp:6(chatterCallback)] [topics: /rosout] I heard: [hi from rostopic pub]
1648577837.847345296 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/topic_manager.cpp:561(TopicManager::pubUpdate)] [topics: /rosout] Received update for topic [/chatter] (2 publishers)
1648577837.847374225 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/subscription.cpp:244(Subscription::pubUpdate)] [topics: /rosout] Publisher update for [/chatter]: http://mimir:44265/, http://mimir:43047/,  already have these connections: http://mimir:44265/, 
1648577837.847490289 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/subscription.cpp:421(Subscription::negotiateConnection)] [topics: /rosout] Began asynchronous xmlrpc connection to [mimir:43047]
1648577838.049727037 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/xmlrpc_manager.cpp:208(XMLRPCManager::validateXmlrpcResponse)] [topics: /rosout] XML-RPC call [requestTopic] didn't return an array
1648577838.049748993 DEBUG /chatter_listener [/tmp/binarydeb/ros-melodic-roscpp-1.14.10/src/libros/subscription.cpp:471(Subscription::pendingConnectionDone)] [topics: /rosout] Failed to contact publisher [mimir:43047] for topic [/chatter]

Topic info:

mimir:~$ rostopic info /chatter
Type: std_msgs/String

Publishers: 
 * /rostopic_31441_1648577829324 (http://mimir:44265/)
 * /foxglovestudio_31584 (http://mimir:43047/)

Subscribers: 
 * /chatter_listener (http://mimir:40991/)
 * /foxglovestudio_31584 (http://mimir:43047/)

[jhurliman]

Fix is landing now: https://github.com/foxglove/studio/pull/3259

[jhurliman]

@jessicaaustin I just updated my examples/ros1-chatter to use @foxglove/xmlrpc 1.2.0 instead of 1.1.9 and I can reproduce your issue now. Looking into the actual cause now, thank you!