Panic on finalization of no-op binding CR

[WAPeterLindsten]

Describe the bug

Operator panic when deleting "invalid" binding CR

To Reproduce

Steps to reproduce the behavior:

1. Create "stupid" binding:

apiVersion: rabbitmq.com/v1beta1
kind: Binding
metadata:
  name: bunny
spec:
  rabbitmqClusterReference:
    name: rabbitmq

2. Wait for attempted reconciliation (which fails with 405 from rabbit cluster, which is fine)
3. Delete stupid binding: kubectl delete bindings.rabbitmq.com/bunny - This command does not return
4. Observe operator pod panic

Expected behavior
Being able to delete this object without operator panic
OR
Not being able to create invalid Custom Resource

Screenshots

No screenshots

Version and environment information

• Messaging Topology Operator: 1.10.1
• RabbitMQ: 3.10.18
• RabbitMQ Cluster Operator: 2.1.0
• Kubernetes: 1.24.6
• Cloud provider or hardware configuration: Openstack

Additional context

Panic log

 manager {"level":"info","ts":"2023-02-17T10:10:18Z","msg":"Deleting","controller":"binding","controllerGroup":"rabbitmq.com","controllerKind":"Binding","Binding":{"name":"bunny","namespace":"service"},"namespace":"service","name":"bunny","reconcileID":"700f2edd-049d-4757-9cc6 │
│ manager {"level":"info","ts":"2023-02-17T10:10:18Z","msg":"Observed a panic in reconciler: runtime error: index out of range [0] with length 0","controller":"binding","controllerGroup":"rabbitmq.com","controllerKind":"Binding","Binding":{"name":"bunny","namespace":"service"}, │
│ manager panic: runtime error: index out of range [0] with length 0 [recovered]                                                                                                                                                                                                       │
│ manager     panic: runtime error: index out of range [0] with length 0                                                                                                                                                                                                               │
│ manager                                                                                                                                                                                                                                                                              │
│ manager goroutine 617 [running]:                                                                                                                                                                                                                                                     │
│ manager sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile.func1()                                                                                                                                                                                       │
│ manager     /go/pkg/mod/sigs.k8s.io/controller-runtime@v0.14.2/pkg/internal/controller/controller.go:119 +0x1fa                                                                                                                                                                      │
│ manager panic({0x18e8a20, 0xc001b54eb8})                                                                                                                                                                                                                                             │
│ manager     /usr/local/go/src/runtime/panic.go:884 +0x212                                                                                                                                                                                                                            │
│ manager github.com/michaelklishin/rabbit-hole/v2.(*Client).DeleteBinding(0x0?, {0x2934d18?, 0x0?}, {{0x0, 0x0}, {0x2934d18, 0x1}, {0x0, 0x0}, {0x0, ...}, ...})                                                                                                                      │
│ manager     /go/pkg/mod/github.com/michaelklishin/rabbit-hole/v2@v2.12.0/bindings.go:218 +0x2ce                                                                                                                                                                                      │
│ manager github.com/rabbitmq/messaging-topology-operator/controllers.(*BindingReconciler).DeleteFunc(0x1d0cd48?, {0x1d0a3e8?, 0xc000c1fd10?}, {0x1d1a670?, 0xc001b577a0?}, {0x1d1ea28?, 0xc000465c00})                                                                                │
│ manager     /workspace/controllers/binding_controller.go:68 +0x29e                                                                                                                                                                                                                   │
│ manager github.com/rabbitmq/messaging-topology-operator/controllers.(*TopologyReconciler).Reconcile(0xc000781710, {0x1d0a3e8, 0xc000c1fd10}, {{{0xc00029eff5?, 0x10?}, {0xc00029eff0?, 0x40dc07?}}})                                                                                 │
│ manager     /workspace/controllers/topology_controller.go:66 +0x48d                                                                                                                                                                                                                  │
│ manager sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Reconcile(0x1d0a3e8?, {0x1d0a3e8?, 0xc000c1fd10?}, {{{0xc00029eff5?, 0x1748a20?}, {0xc00029eff0?, 0x0?}}})                                                                                              │
│ manager     /go/pkg/mod/sigs.k8s.io/controller-runtime@v0.14.2/pkg/internal/controller/controller.go:122 +0xc8                                                                                                                                                                       │
│ manager sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler(0xc000386c80, {0x1d0a340, 0xc0007bd940}, {0x183a120?, 0xc000bbc500?})                                                                                                                  │
│ manager     /go/pkg/mod/sigs.k8s.io/controller-runtime@v0.14.2/pkg/internal/controller/controller.go:323 +0x38f                                                                                                                                                                      │
│ manager sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem(0xc000386c80, {0x1d0a340, 0xc0007bd940})                                                                                                                                            │
│ manager     /go/pkg/mod/sigs.k8s.io/controller-runtime@v0.14.2/pkg/internal/controller/controller.go:274 +0x1d9                                                                                                                                                                      │
│ manager sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2.2()                                                                                                                                                                                         │
│ manager     /go/pkg/mod/sigs.k8s.io/controller-runtime@v0.14.2/pkg/internal/controller/controller.go:235 +0x85                                                                                                                                                                       │
│ manager created by sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2                                                                                                                                                                                  │
│ manager     /go/pkg/mod/sigs.k8s.io/controller-runtime@v0.14.2/pkg/internal/controller/controller.go:231 +0x333                                                                                                                                                                      │
│ Stream closed EOF for rabbitmq-system/messaging-topology-operator-79f79b5857-z5vf2 (manager)

[ChunyiLyu]

@WAPeterLindsten Hi Peter, thanks for finding this bug. The fix will be out next time we cut a release.