openstack router remove/add command out without error, when it fails

the command fails but the failure is not shown if you don't use --debug option:

(overcloud) [stack@undercloud-0 ~]$ openstack router remove subnet router selfservice ; echo $?
0
(overcloud) [stack@undercloud-0 ~]$
(overcloud) [stack@undercloud-0 ~]$
(overcloud) [stack@undercloud-0 ~]$ openstack router add subnet router selfservice ; echo $?
0

(overcloud) [stack@undercloud-0 ~]$ openstack router remove subnet router selfservice --debug
START with options: [u'router', u'remove', u'subnet', u'router', u'selfservice', u'--debug']
...

RESP: [409] Content-Length: 268 Content-Type: application/json Date: Fri, 22 Mar 2019 09:29:10 GMT X-Openstack-Request-Id: req-e46e3e8b-76d3-4535-8cad-e14eed2c9190
RESP BODY: {"NeutronError": {"message": "Router interface for subnet ca7de33b-98c7-4ff4-9fae-cc2fcb7c41cc on router daa62d34-037d-4188-a37c-ab5d058d5489 cannot be deleted, as it is required by one or more floating IPs.", "type": "RouterInterfaceInUseByFloatingIP", "detail": ""}}
PUT call to network for http://10.0.0.107:9696/v2.0/routers/daa62d34-037d-4188-a37c-ab5d058d5489/remove_router_interface used request id req-e46e3e8b-76d3-4535-8cad-e14eed2c9190
Manager unknown ran task network.PUT.routers.remove_router_interface in 1.10061788559s
clean_up RemoveSubnetFromRouter:
END return value: 0
(overcloud) [stack@undercloud-0 ~]$

Reproduction example:

 -create a router:

(overcloud) [stack@undercloud-0 ~]$ history | grep router
   18 openstack router create router
   19 openstack router add subnet router selfservice
   20 openstack router set router --external-gateway public

 -associate a floating ip to a vm:
   56 openstack server add floating ip provider-instance 10.0.0.216

 -try to add/remove the subnet

   61 openstack router remove subnet router selfservice --debug
   62 openstack router add subnet router selfservice --debug

Logs and versio:

(overcloud) [stack@undercloud-0 ~]$ yum info openstack-neutron
Loaded plugins: search-disabled-repos
Available Packages
Name : openstack-neutron
Arch : noarch
Epoch : 1
Version : 13.0.3
Release : 0.20190119134915.886782c.el7ost
Size : 28 k
Repo : rhelosp-14.0-puddle/x86_64
Summary : OpenStack Networking Service
URL : http://launchpad.net/neutron/
License : ASL 2.0
Description :
            : Neutron is a virtual network service for Openstack. Just like
            : OpenStack Nova provides an API to dynamically request and configure
            : virtual servers, Neutron provides an API to dynamically request and
            : configure virtual networks. These networks connect "interfaces" from
            : other OpenStack services (e.g., virtual NICs from Nova VMs). The
            : Neutron API supports extensions to provide advanced network
            : capabilities (e.g., QoS, ACLs, network monitoring, etc.)

(overcloud) [stack@undercloud-0 ~]$ cat /etc/rhosp-release
Red Hat OpenStack Platform release 14.0.1 RC (Rocky)

(overcloud) [stack@undercloud-0 ~]$ openstack server add floating ip provider-instance 10.0.0.216
(overcloud) [stack@undercloud-0 ~]$ openstack router remove subnet router selfservice
(overcloud) [stack@undercloud-0 ~]$
(overcloud) [stack@undercloud-0 ~]$
(overcloud) [stack@undercloud-0 ~]$
(overcloud) [stack@undercloud-0 ~]$ openstack router show router
+-------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Field | Value |
+-------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| admin_state_up | UP |
| availability_zone_hints | |
| availability_zones | nova |
| created_at | 2019-03-22T08:54:12Z |
| description | |
| distributed | None |
| external_gateway_info | {"network_id": "ef3db5e4-8e6e-4e40-8575-c8f3400e21aa", "enable_snat": true, "external_fixed_ips": [{"subnet_id": "e74f8ff3-cf78-47a9-8fea-ef6612749988", "ip_address": "10.0.0.213"}]} |
| flavor_id | None |
| ha | None |
| id | daa62d34-037d-4188-a37c-ab5d058d5489 |
| interfaces_info | [{"subnet_id": "ca7de33b-98c7-4ff4-9fae-cc2fcb7c41cc", "ip_address": "10.1.0.1", "port_id": "b2872491-a430-4560-ada3-1e02695fa74f"}, {"subnet_id": "ca7de33b-98c7-4ff4-9fae-cc2fcb7c41cc", "ip_address": "10.1.0.26", "port_id": "be992a1f-de15-473e-bc52-2e79faa2b0e0"}] |
| name | router |
| project_id | c4b7aee7b6404c24aa7b33428e9ad271 |
| revision_number | 4 |
| routes | |
| status | ACTIVE |
| tags | |
| updated_at | 2019-03-22T08:54:45Z |
+-------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
(overcloud) [stack@undercloud-0 ~]$
(overcloud) [stack@undercloud-0 ~]$
(overcloud) [stack@undercloud-0 ~]$ openstack router remove subnet router selfservice ; echo $?
0
(overcloud) [stack@undercloud-0 ~]$
(overcloud) [stack@undercloud-0 ~]$
(overcloud) [stack@undercloud-0 ~]$ openstack router add subnet router selfservice ; echo $?
0
(overcloud) [stack@undercloud-0 ~]$ openstack router remove subnet router selfservice --debug
START with options: [u'router', u'remove', u'subnet', u'router', u'selfservice', u'--debug']
...
....
489/remove_router_interface HTTP/1.1" 409 268
RESP: [409] Content-Length: 268 Content-Type: application/json Date: Fri, 22 Mar 2019 09:29:10 GMT X-Openstack-Request-Id: req-e46e3e8b-76d3-4535-8cad-e14eed2c9190
RESP BODY: {"NeutronError": {"message": "Router interface for subnet ca7de33b-98c7-4ff4-9fae-cc2fcb7c41cc on router daa62d34-037d-4188-a37c-ab5d058d5489 cannot be deleted, as it is required by one or more floating IPs.", "type": "RouterInterfaceInUseByFloatingIP", "detail": ""}}
PUT call to network for http://10.0.0.107:9696/v2.0/routers/daa62d34-037d-4188-a37c-ab5d058d5489/remove_router_interface used request id req-e46e3e8b-76d3-4535-8cad-e14eed2c9190
Manager unknown ran task network.PUT.routers.remove_router_interface in 1.10061788559s
clean_up RemoveSubnetFromRouter:
END return value: 0
(overcloud) [stack@undercloud-0 ~]$
(overcloud) [stack@undercloud-0 ~]$
(overcloud) [stack@undercloud-0 ~]$ openstack router add subnet router selfservice --debug
START with options: [u'router', u'add', u'subnet', u'router', u'selfservice', u'--debug']

...............................

/10.0.0.107:9696/v2.0/routers used request id req-a0cc03ac-41ab-4778-9d34-c0cb09ed7c1b
Manager unknown ran task network.GET.routers in 0.708297967911s
Manager unknown running task network.PUT.routers.add_router_interface
REQ: curl -g -i -X PUT http://10.0.0.107:9696/v2.0/routers/daa62d34-037d-4188-a37c-ab5d058d5489/add_router_interface -H "Content-Type: application/json" -H "User-Agent: openstacksdk/0.17.2 keystoneauth1/3.10.0 python-requests/2.19.1 CPython/2.7.5" -H "X-Auth-Token: {SHA1}9a5402393205c1bd2bf71649ed6b08c29893541a" -d '{"subnet_id": "ca7de33b-98c7-4ff4-9fae-cc2fcb7c41cc"}'
http://10.0.0.107:9696 "PUT /v2.0/routers/daa62d34-037d-4188-a37c-ab5d058d5489/add_router_interface HTTP/1.1" 400 162
RESP: [400] Content-Length: 162 Content-Type: application/json Date: Fri, 22 Mar 2019 09:29:40 GMT X-Openstack-Request-Id: req-4480dc18-562c-4abc-ad29-1b09f38d479d
RESP BODY: {"NeutronError": {"message": "Bad router request: Router already has a port on subnet ca7de33b-98c7-4ff4-9fae-cc2fcb7c41cc.", "type": "BadRequest", "detail": ""}}
PUT call to network for http://10.0.0.107:9696/v2.0/routers/daa62d34-037d-4188-a37c-ab5d058d5489/add_router_interface used request id req-4480dc18-562c-4abc-ad29-1b09f38d479d
Manager unknown ran task network.PUT.routers.add_router_interface in 0.781075954437s
clean_up AddSubnetToRouter:
END return value: 0
(overcloud) [stack@undercloud-0 ~]$

(overcloud) [stack@undercloud-0 ~]$ openstack router show router
+-------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Field | Value |
+-------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| admin_state_up | UP |
| availability_zone_hints | |
| availability_zones | nova |
| created_at | 2019-03-22T08:54:12Z |
| description | |
| distributed | None |
| external_gateway_info | {"network_id": "ef3db5e4-8e6e-4e40-8575-c8f3400e21aa", "enable_snat": true, "external_fixed_ips": [{"subnet_id": "e74f8ff3-cf78-47a9-8fea-ef6612749988", "ip_address": "10.0.0.213"}]} |
| flavor_id | None |
| ha | None |
| id | daa62d34-037d-4188-a37c-ab5d058d5489 |
| interfaces_info | [{"subnet_id": "ca7de33b-98c7-4ff4-9fae-cc2fcb7c41cc", "ip_address": "10.1.0.1", "port_id": "b2872491-a430-4560-ada3-1e02695fa74f"}, {"subnet_id": "ca7de33b-98c7-4ff4-9fae-cc2fcb7c41cc", "ip_address": "10.1.0.26", "port_id": "be992a1f-de15-473e-bc52-2e79faa2b0e0"}] |
| name | router |
| project_id | c4b7aee7b6404c24aa7b33428e9ad271 |
| revision_number | 4 |
| routes | |
| status | ACTIVE |
| tags | |
| updated_at | 2019-03-22T08:54:45Z |
+-------------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+