Jupyter ignores an error response on `kernel_info_request`

[ntisseyre]

If my kernel sends an error response for the kernel_info_request, jupyter console still starts without any error. Here is the log of request/response from my custom kernel:

--Request for channel=Requests, Message(Vector(ArraySeq(53, 101, 50, 98, 49, 49, 57, 98, 45, 101, 98, 100, 49, 48, 97, 52, 97, 98, 56, 100, 98, 52, 55, 53, 99, 53, 56, 100, 100, 57, 52, 56, 49)),{"msg_id":"9d139b2f-b1ca8e0d5e069ff871ab5755","msg_type":"kernel_info_request","username":"nataliatisseyre","session":"5e2b119b-ebd10a4ab8db475c58dd9481","date":"2019-10-14T17:43:18.970182Z","version":"5.3"},{},{},{})
--Request for channel=Requests, Message(Vector(ArraySeq(53, 101, 50, 98, 49, 49, 57, 98, 45, 101, 98, 100, 49, 48, 97, 52, 97, 98, 56, 100, 98, 52, 55, 53, 99, 53, 56, 100, 100, 57, 52, 56, 49)),{"msg_id":"6d12b8cd-0205da96ae3c659fb7210b5d","msg_type":"kernel_info_request","username":"nataliatisseyre","session":"5e2b119b-ebd10a4ab8db475c58dd9481","date":"2019-10-14T17:43:18.972761Z","version":"5.3"},{},{},{})
Response for channel=Requests, Message(List(ArraySeq(53, 101, 50, 98, 49, 49, 57, 98, 45, 101, 98, 100, 49, 48, 97, 52, 97, 98, 56, 100, 98, 52, 55, 53, 99, 53, 56, 100, 100, 57, 52, 56, 49)),{"msg_id":"220b40d3-5aee-4768-8d1b-f8b6aae1988f","username":"nataliatisseyre","msg_type":"error","version":"5.3","session":"5e2b119b-ebd10a4ab8db475c58dd9481"},{"msg_id":"9d139b2f-b1ca8e0d5e069ff871ab5755","username":"nataliatisseyre","msg_type":"kernel_info_request","version":"5.3","session":"5e2b119b-ebd10a4ab8db475c58dd9481"},{},{"traceback":["Limit of concurrent sessions has been reached"],"evalue":"","ename":""})
Response for channel=Requests, Message(List(ArraySeq(53, 101, 50, 98, 49, 49, 57, 98, 45, 101, 98, 100, 49, 48, 97, 52, 97, 98, 56, 100, 98, 52, 55, 53, 99, 53, 56, 100, 100, 57, 52, 56, 49)),{"msg_id":"f716a37a-54c6-447f-b758-214a7431f360","username":"nataliatisseyre","msg_type":"error","version":"5.3","session":"5e2b119b-ebd10a4ab8db475c58dd9481"},{"msg_id":"6d12b8cd-0205da96ae3c659fb7210b5d","username":"nataliatisseyre","msg_type":"kernel_info_request","version":"5.3","session":"5e2b119b-ebd10a4ab8db475c58dd9481"},{},{"traceback":["Limit of concurrent sessions has been reached"],"evalue":"","ename":""})

I'm also wondering why there are 2 requests for the same session?