What happened:
got this in the 8.0.1 snapshotter while developing our CSI drivers volumegroupsnapshot logic, even though my code
is problematic and not complete, I would expect the snapshotter to not panic.

0730 20:20:28.055041 1 snapshot_controller.go:595] Removed protection finalizer from volume snapshot content snapcontent-13f1a3900670d351195c9d814444c5957f3cc787f79e36f934eef7f669bff83b-2024-07-30-7.52.43
I0730 20:20:28.055064 1 util.go:264] storeObjectUpdate updating content "snapcontent-13f1a3900670d351195c9d814444c5957f3cc787f79e36f934eef7f669bff83b-2024-07-30-7.52.43" with version 2385585
E0730 20:20:28.055275 1 groupsnapshot_helper.go:157] could not sync group snapshot content "groupsnapcontent-b09c477c-0e10-4900-888a-e5d676fbe236": failed to delete group snapshot "groupsnapcontent-b09c477c-0e10-4900-888a-e5d676fbe236", err: cannot delete group snapshot content groupsnapcontent-b09c477c-0e10-4900-888a-e5d676fbe236. No snapshots found in the group snapshot
I0730 20:20:28.055297 1 groupsnapshot_helper.go:79] Failed to sync group snapshot content "groupsnapcontent-b09c477c-0e10-4900-888a-e5d676fbe236", will retry again: failed to delete group snapshot "groupsnapcontent-b09c477c-0e10-4900-888a-e5d676fbe236", err: cannot delete group snapshot content groupsnapcontent-b09c477c-0e10-4900-888a-e5d676fbe236. No snapshots found in the group snapshot
I0730 20:20:28.055328 1 event.go:377] Event(v1.ObjectReference{Kind:"VolumeGroupSnapshotContent", Namespace:"", Name:"groupsnapcontent-b09c477c-0e10-4900-888a-e5d676fbe236", UID:"392530a9-7938-4e96-aecd-7ad7c7c93452", APIVersion:"groupsnapshot.storage.k8s.io/v1alpha1", ResourceVersion:"2304318", FieldPath:""}): type: 'Warning' reason: 'GroupSnapshotDeleteError' Failed to delete group snapshot
E0730 20:20:28.056504 1 groupsnapshot_helper.go:157] could not sync group snapshot content "groupsnapcontent-cf45513b-9cf3-4c36-9566-b2c15889decc": failed to delete group snapshot "groupsnapcontent-cf45513b-9cf3-4c36-9566-b2c15889decc", err: cannot delete group snapshot content groupsnapcontent-cf45513b-9cf3-4c36-9566-b2c15889decc. No snapshots found in the group snapshot
I0730 20:20:28.056521 1 groupsnapshot_helper.go:79] Failed to sync group snapshot content "groupsnapcontent-cf45513b-9cf3-4c36-9566-b2c15889decc", will retry again: failed to delete group snapshot "groupsnapcontent-cf45513b-9cf3-4c36-9566-b2c15889decc", err: cannot delete group snapshot content groupsnapcontent-cf45513b-9cf3-4c36-9566-b2c15889decc. No snapshots found in the group snapshot
I0730 20:20:28.056545 1 event.go:377] Event(v1.ObjectReference{Kind:"VolumeGroupSnapshotContent", Namespace:"", Name:"groupsnapcontent-cf45513b-9cf3-4c36-9566-b2c15889decc", UID:"494c793f-7d00-4b4c-acb4-b917716d5570", APIVersion:"groupsnapshot.storage.k8s.io/v1alpha1", ResourceVersion:"2314362", FieldPath:""}): type: 'Warning' reason: 'GroupSnapshotDeleteError' Failed to delete group snapshot
I0730 20:20:28.057393 1 snapshot_controller_base.go:206] enqueued "snapcontent-13f1a3900670d351195c9d814444c5957f3cc787f79e36f934eef7f669bff83b-2024-07-30-7.52.43" for sync
I0730 20:20:28.057414 1 snapshot_controller_base.go:247] syncContentByKey[snapcontent-13f1a3900670d351195c9d814444c5957f3cc787f79e36f934eef7f669bff83b-2024-07-30-7.52.43]
I0730 20:20:28.057428 1 snapshot_controller_base.go:367] content "snapcontent-13f1a3900670d351195c9d814444c5957f3cc787f79e36f934eef7f669bff83b-2024-07-30-7.52.43" deleted
E0730 20:20:28.059942 1 runtime.go:79] Observed a panic: "invalid memory address or nil pointer dereference" (runtime error: invalid memory address or nil pointer dereference)
goroutine 53 [running]:
k8s.io/apimachinery/pkg/util/runtime.logPanic({0x19f7de0, 0x2dbdf00})
/workspace/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:75 +0x85
k8s.io/apimachinery/pkg/util/runtime.HandleCrash({0x0, 0x0, 0xc0004d20f0?})
/workspace/vendor/k8s.io/apimachinery/pkg/util/runtime/runtime.go:49 +0x6b
panic({0x19f7de0?, 0x2dbdf00?})
/go/pkg/csiprow.XXXXhhNCeB/go-1.22.3/src/runtime/panic.go:770 +0x132
github.com/kubernetes-csi/external-snapshotter/v8/pkg/sidecar-controller.(*csiSnapshotSideCarController).deleteCSIGroupSnapshotOperation(0xc000180a20, 0xc00040e000)
/workspace/pkg/sidecar-controller/groupsnapshot_helper.go:256 +0x4c8
github.com/kubernetes-csi/external-snapshotter/v8/pkg/sidecar-controller.(*csiSnapshotSideCarController).syncGroupSnapshotContent(0xc000180a20, 0xc00040e000)
/workspace/pkg/sidecar-controller/groupsnapshot_helper.go:184 +0x47d
github.com/kubernetes-csi/external-snapshotter/v8/pkg/sidecar-controller.(*csiSnapshotSideCarController).updateGroupSnapshotContentInInformerCache(0xc000180a20, 0xc00040e000)
/workspace/pkg/sidecar-controller/groupsnapshot_helper.go:150 +0x12d
github.com/kubernetes-csi/external-snapshotter/v8/pkg/sidecar-controller.(*csiSnapshotSideCarController).syncGroupSnapshotContentByKey(0xc000180a20, {0xc000059980, 0x35})
/workspace/pkg/sidecar-controller/groupsnapshot_helper.go:102 +0x707
github.com/kubernetes-csi/external-snapshotter/v8/pkg/sidecar-controller.(*csiSnapshotSideCarController).groupSnapshotContentWorker(0xc000180a20)
/workspace/pkg/sidecar-controller/groupsnapshot_helper.go:75 +0xf3
k8s.io/apimachinery/pkg/util/wait.BackoffUntil.func1(0x30?)
/workspace/vendor/k8s.io/apimachinery/pkg/util/wait/backoff.go:226 +0x33
k8s.io/apimachinery/pkg/util/wait.BackoffUntil(0xc00080a340, {0x1f58d40, 0xc0003e5dd0}, 0x1, 0xc0000b77a0)
/workspace/vendor/k8s.io/apimachinery/pkg/util/wait/backoff.go:227 +0xaf
k8s.io/apimachinery/pkg/util/wait.JitterUntil(0xc00080a340, 0x0, 0x0, 0x1, 0xc0000b77a0)
/workspace/vendor/k8s.io/apimachinery/pkg/util/wait/backoff.go:204 +0x7f
k8s.io/apimachinery/pkg/util/wait.Until(...)
/workspace/vendor/k8s.io/apimachinery/pkg/util/wait/backoff.go:161
created by github.com/kubernetes-csi/external-snapshotter/v8/pkg/sidecar-controller.(*csiSnapshotSideCarController).Run in goroutine 76
/workspace/pkg/sidecar-controller/snapshot_controller_base.go:187 +0x3d0
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x17de408]

snapshotter sidecar panic

What you expected to happen:
just throw errors

How to reproduce it:
construct CreateVolumeGroupSnapshotResponse with invalid snapshots or remove snapshots on the storage device or have resources not cleaned up properly due to errors.

Anything else we need to know?:

Environment:

• Driver version: 8.0.1
• Kubernetes version (use kubectl version): v1.30.1+k3s1
• OS (e.g. from /etc/os-release): ubuntu
• Kernel (e.g. uname -a):
• Install tools: k3s
• Others: