K8SPXC-1851: Fix potential nil pointer dereference in pkg/pxc/backup/restore.go

[DimitriosLisenko]

Just a quick thing I noticed while implementing another feature. There is a logic bug in pkg/pxc/backup/restore.go that checks if cluster.Spec.Backup is is nil and if so, calls cluster.Spec.Backup.Storages.

[CLAassistant]

All committers have signed the CLA.

[egegunes]

I don't understand why we have this check here, maybe @pooknull remembers.

[gkech]

Let's cover this with a unit test cause these kind of errors are easy to surface without testing, like 2 scenarios, nil backup spec returns error and empty storages map returns error

[pooknull]

I don't remember why I added this check in the #1521. It no longer makes sense to me, so I removed it

[JNKPercona]

Test Name	Result	Time
auto-tuning-8-0	passed	00:21:59
allocator-8-0	passed	00:14:21
allocator-8-4	passed	00:14:45
backup-storage-tls-8-0	passed	00:25:03
cross-site-8-0	passed	00:40:06
cross-site-proxysql-8-0	passed	00:47:13
cross-site-proxysql-8-4	passed	00:44:57
custom-users-8-0	passed	00:15:29
demand-backup-cloud-8-0	passed	01:07:29
demand-backup-cloud-8-4	passed	01:05:02
demand-backup-cloud-pxb-8-0	failure	00:40:08
demand-backup-encrypted-with-tls-5-7	passed	00:51:41
demand-backup-encrypted-with-tls-8-0	passed	00:51:14
demand-backup-encrypted-with-tls-8-4	passed	00:51:06
demand-backup-encrypted-with-tls-pxb-5-7	passed	00:19:36
demand-backup-encrypted-with-tls-pxb-8-0	passed	00:19:54
demand-backup-encrypted-with-tls-pxb-8-4	passed	00:20:24
demand-backup-8-0	passed	00:48:59
demand-backup-flow-control-8-0	passed	00:12:00
demand-backup-flow-control-8-4	passed	00:12:40
demand-backup-parallel-8-0	passed	00:10:53
demand-backup-parallel-8-4	passed	00:10:44
demand-backup-without-passwords-8-0	passed	00:17:59
demand-backup-without-passwords-8-4	passed	00:18:35
extra-pvc-8-0	passed	00:28:37
haproxy-5-7	passed	00:16:56
haproxy-8-0	passed	00:16:44
haproxy-8-4	passed	00:16:52
init-deploy-5-7	passed	00:20:58
init-deploy-8-0	passed	00:20:26
limits-8-0	passed	00:13:59
monitoring-2-0-8-0	passed	00:24:49
monitoring-pmm3-8-0	passed	00:20:19
monitoring-pmm3-8-4	passed	00:19:55
one-pod-5-7	passed	00:14:51
one-pod-8-0	passed	00:14:40
pitr-8-0	passed	00:52:17
pitr-8-4	passed	01:03:40
pitr-pxb-8-0	failure	00:41:06
pitr-pxb-8-4	failure	00:47:45
pitr-gap-errors-8-0	passed	00:54:37
pitr-gap-errors-8-4	passed	00:54:00
proxy-protocol-8-0	passed	00:20:56
proxy-switch-8-0	passed	00:14:42
proxysql-sidecar-res-limits-8-0	passed	00:09:14
proxysql-scheduler-8-0	passed	00:28:35
pvc-resize-5-7	passed	00:20:46
pvc-resize-8-0	passed	00:18:26
recreate-8-0	passed	00:20:23
restore-to-encrypted-cluster-8-0	passed	00:37:20
restore-to-encrypted-cluster-8-4	passed	00:29:47
restore-to-encrypted-cluster-pxb-8-0	passed	00:18:28
restore-to-encrypted-cluster-pxb-8-4	passed	00:18:16
scaling-proxysql-8-0	passed	00:10:16
scaling-8-0	passed	00:12:52
scheduled-backup-5-7	passed	01:12:41
scheduled-backup-8-0	passed	01:10:47
scheduled-backup-8-4	passed	01:09:52
security-context-8-0	passed	00:27:43
smart-update1-8-0	passed	00:39:39
smart-update1-8-4	passed	00:38:47
smart-update2-8-0	passed	00:44:36
smart-update2-8-4	passed	00:44:27
smart-update3-8-0	passed	00:18:33
sst-retry-limit-8-0	passed	00:15:14
sst-retry-limit-8-4	passed	00:15:55
storage-8-0	passed	00:12:14
tls-issue-cert-manager-ref-8-0	passed	00:10:54
tls-issue-cert-manager-8-0	passed	00:11:06
tls-issue-self-8-0	passed	00:15:31
upgrade-consistency-8-0	passed	00:13:14
upgrade-consistency-8-4	passed	00:16:56
upgrade-haproxy-5-7	passed	00:28:54
upgrade-haproxy-8-0	passed	00:28:09
upgrade-proxysql-5-7	passed	00:18:29
upgrade-proxysql-8-0	passed	00:17:21
users-5-7	passed	00:32:23
users-8-0	passed	00:31:24
users-scheduler-8-4	passed	00:29:24
validation-hook-8-0	passed	00:02:07

Summary	Value
Tests Run	80/80
Job Duration	04:05:29
Total Test Time	37:51:49

commit: edfc6c2
image: perconalab/percona-xtradb-cluster-operator:PR-2423-edfc6c27