lost host after merge zone

[HarrisChu]

steps:
start 3 metad, and 2 storage with 14814 and 18271 port

1. add host 127.0.0.1:14814 into new zone "default_zone"
2. add host 127.0.0.1:18271 into new zone "test_zone"
3. add host "invalid":9779 into new zone "invalid_zone"
4. MERGE ZONE "test_zone","invalid_zone" INTO "default_zone"
5. SHOW ZONES

result:
lost a host in show zones

E   AssertionError: Fail to exec: SHOW ZONES
E     Response: |Name|Host|Port|
E     0: |default_zone|invalid|9779|
E     1: |default_zone|127.0.0.1|14814|
E     Expected: |Name|Host|Port|
E     0: |default_zone|127.0.0.1|14814|
E     1: |default_zone|127.0.0.1|18271|
E     2: |default_zone|invalid|9779|
E     NotFoundRow: 1: |default_zone|127.0.0.1|18271|

(root@nebula) [(none)]> show zones
+----------------+-------------+-------+
| Name           | Host        | Port  |
+----------------+-------------+-------+
| "default_zone" | "invalid"   | 9779  |
| "default_zone" | "127.0.0.1" | 16912 |
+----------------+-------------+-------+
Got 2 rows (time spent 2472/8066 us)

Fri, 07 Jan 2022 11:14:16 CST

(root@nebula) [(none)]> show hosts
+-------------+-------+-----------+--------------+----------------------+------------------------+
| Host        | Port  | Status    | Leader count | Leader distribution  | Partition distribution |
+-------------+-------+-----------+--------------+----------------------+------------------------+
| "127.0.0.1" | 16912 | "ONLINE"  | 0            | "No valid partition" | "No valid partition"   |
| "127.0.0.1" | 10320 | "ONLINE"  | 0            | "No valid partition" | "No valid partition"   |
| "invalid"   | 9779  | "OFFLINE" | 0            | "No valid partition" | "No valid partition"   |
| "Total"     |       |           | 0            |                      |                        |
+-------------+-------+-----------+--------------+----------------------+------------------------+
Got 4 rows (time spent 2635/7335 us)

Fri, 07 Jan 2022 11:15:22 CST

(root@nebula) [(none)]>

[darionyaphet]

if so, you should use the following command:

MERGE ZONE "test_zone","invalid_zone","default_zone" INTO "default_zone"

And I will support more check to avoid it later.