Knot crashes on reload when no interfaces configured
With Knot 3.1.3, if the config file has no "listen" directives in the "server" section of the config, the daemon will start. It will log a warning about no interfaces configured. But then, when I try to reload the config by sending it a HUP signal, it crashes. See these two logs, the first in the file written by knot directly, and the second is the systemd log:
2021-10-18T20:39:06+0000 info: Knot DNS 3.1.3 starting
2021-10-18T20:39:06+0000 info: loaded configuration file '/etc/knot/knot.conf', mapsize 500 MiB
2021-10-18T20:39:06+0000 warning: no network interface configured
2021-10-18T20:39:06+0000 info: changing GID to 10073
2021-10-18T20:39:06+0000 info: changing UID to 10073
2021-10-18T20:39:06+0000 info: loading 2 zones
2021-10-18T20:39:06+0000 info: [ripe.net.] zone will be loaded
2021-10-18T20:39:06+0000 info: [probes.atlas.ripe.net.] zone will be loaded
2021-10-18T20:39:06+0000 info: starting server
2021-10-18T20:39:06+0000 info: [probes.atlas.ripe.net.] zone loaded from journal, serial 1634589061
2021-10-18T20:39:06+0000 info: [probes.atlas.ripe.net.] loaded, serial none -> 1634589061, 4052583 bytes
2021-10-18T20:39:06+0000 info: [ripe.net.] zone loaded from journal, serial 1634566096
2021-10-18T20:39:06+0000 info: [ripe.net.] loaded, serial none -> 1634566096, 4191638 bytes
2021-10-18T20:39:06+0000 info: server started in the foreground, PID 5593
2021-10-18T20:39:06+0000 info: control, binding to '/var/run/knot/knot.sock'
2021-10-18T20:40:41+0000 info: reloading configuration file '/etc/knot/knot.conf'
Oct 18 20:40:41 ns1.nl-ams.testdns.ripe.net systemd[1]: Reloading Knot DNS Server.
Oct 18 20:40:41 ns1.nl-ams.testdns.ripe.net systemd[1]: Reloaded Knot DNS Server.
Oct 18 20:40:41 ns1.nl-ams.testdns.ripe.net knotd[5593]: knotd: knot/server/server.c:867: listen_changed: Assertion `server->ifaces' failed.
Oct 18 20:40:41 ns1.nl-ams.testdns.ripe.net systemd[1]: knot.service: main process exited, code=killed, status=6/ABRT
Oct 18 20:40:41 ns1.nl-ams.testdns.ripe.net systemd[1]: Unit knot.service entered failed state.
Oct 18 20:40:41 ns1.nl-ams.testdns.ripe.net systemd[1]: knot.service failed.