In the web interface, one cannot create new child nodes from the root node without specifying an id.
This error is confined to the web interface, as curl works normally:
curl -X POST localhost:8080/fcrepo/rest
curl -X POST localhost:8080/fcrepo/rest/
Both return the expected values.
But at http://localhost:8080/fcrepo/rest/, clicking on the "Add" button gives me this response:
Path contains empty element! //a2/fb/cc/a0/a2fbcca0-bbdb-4c75-b40e-430d024b8451