panic when using PodDisruptionBudget (pdb) filter

[upr-kmd]

Checklist

• I've searched for similar issues and couldn't find anything matching
• I've included steps to reproduce the behavior

Affected Components

• K8sGPT (CLI)
• K8sGPT Operator

K8sGPT Version

v0.3.15, v0.3.9

Kubernetes Version

v1.25.11+1485cc9

Host OS and its Version

Ubuntu 22.04.3

Steps to reproduce

v0.3.15

$ k8sgpt analyze --filter PodDisruptionBudget
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x1e95a69]

goroutine 22 [running]:
github.com/k8sgpt-ai/k8sgpt/pkg/analyzer.PdbAnalyzer.Analyze({}, {0xc0007e2120, {0x2c73560, 0xc000054130}, {0x0, 0x0}, {0x2c73c98, 0x3fc8bc0}, 0x0, {0x0, ...}, ...})
        /home/runner/work/k8sgpt/k8sgpt/pkg/analyzer/pdb.go:61 +0x409
github.com/k8sgpt-ai/k8sgpt/pkg/analysis.(*Analysis).RunAnalysis.func2({0x2c576a0?, 0x4008160?}, {0xc000843320, 0x13})
        /home/runner/work/k8sgpt/k8sgpt/pkg/analysis/analysis.go:198 +0xe2
created by github.com/k8sgpt-ai/k8sgpt/pkg/analysis.(*Analysis).RunAnalysis
        /home/runner/work/k8sgpt/k8sgpt/pkg/analysis/analysis.go:196 +0x8df
$ oc get  PodDisruptionBudget -A
NAMESPACE                              NAME                                    MIN AVAILABLE   MAX UNAVAILABLE   ALLOWED DISRUPTIONS   AGE
eck                                    elasticsearch-pwk-es-default            N/A             1                 0                     17d
openshift-apiserver                    openshift-apiserver-pdb                 N/A             1                 1                     651d
openshift-cluster-csi-drivers          azure-disk-csi-driver-controller-pdb    N/A             1                 1                     479d
openshift-cluster-csi-drivers          azure-file-csi-driver-controller-pdb    N/A             1                 1                     308d
openshift-cluster-storage-operator     csi-snapshot-controller-pdb             N/A             1                 1                     651d
openshift-cluster-storage-operator     csi-snapshot-webhook-pdb                N/A             1                 1                     651d
openshift-console                      console                                 N/A             1                 1                     308d
openshift-console                      downloads                               N/A             1                 1                     308d
openshift-etcd                         etcd-guard-pdb                          2               N/A               1                     22d
openshift-image-registry               image-registry                          1               N/A               1                     651d
openshift-ingress                      router-default                          N/A             50%               1                     651d
openshift-kube-apiserver               kube-apiserver-guard-pdb                2               N/A               1                     479d
openshift-kube-controller-manager      kube-controller-manager-guard-pdb       2               N/A               1                     479d
openshift-kube-scheduler               openshift-kube-scheduler-guard-pdb      2               N/A               1                     479d
openshift-monitoring                   alertmanager-main                       N/A             1                 1                     479d
openshift-monitoring                   prometheus-adapter                      1               N/A               1                     651d
openshift-monitoring                   prometheus-k8s                          1               N/A               1                     479d
openshift-monitoring                   prometheus-operator-admission-webhook   1               N/A               1                     308d
openshift-monitoring                   thanos-querier-pdb                      1               N/A               1                     651d
openshift-oauth-apiserver              oauth-apiserver-pdb                     N/A             1                 1                     651d
openshift-operator-lifecycle-manager   packageserver-pdb                       N/A             1                 1                     651d
openshift-ovn-kubernetes               ovn-raft-quorum-guard                   2               N/A               1                     651d
openshift-user-workload-monitoring     prometheus-user-workload                1               N/A               1                     479d
openshift-user-workload-monitoring     thanos-ruler-user-workload              1               N/A               1                     479d

v0.3.9

$ ./k8sgpt version
k8sgpt: 0.3.9 (ad112ea), built at: unknown

$ ./k8sgpt analyze --filter PodDisruptionBudget
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x1e4bde9]

goroutine 13 [running]:
github.com/k8sgpt-ai/k8sgpt/pkg/analyzer.PdbAnalyzer.Analyze({}, {0xc000797ec0, {0x2a58710, 0xc00011c028}, {0x0, 0x0}, {0x2a58e10, 0x3d6bb60}, 0x0, {0x0, ...}, ...})
        /home/runner/work/k8sgpt/k8sgpt/pkg/analyzer/pdb.go:61 +0x409
github.com/k8sgpt-ai/k8sgpt/pkg/analysis.(*Analysis).RunAnalysis.func2({0x2a3d380?, 0x3dab0b8?}, {0xc0008565e8, 0x13})
        /home/runner/work/k8sgpt/k8sgpt/pkg/analysis/analysis.go:198 +0xe2
created by github.com/k8sgpt-ai/k8sgpt/pkg/analysis.(*Analysis).RunAnalysis
        /home/runner/work/k8sgpt/k8sgpt/pkg/analysis/analysis.go:196 +0x8df

Expected behaviour

No panic :)

Actual behaviour

Application crashes

Additional Information

No response

[AlexsJones]

My initial guess is this line pdb.Spec.Selector.MatchLabels means there are labels missing on the pdb spec.
Of couse it shouldn't panic so I'll put in a predictive fix and you can tell me how it looks okay?

[AlexsJones]

#664