[Owen-CH-Leung]

Summary

Bug: Removing cnSpec from a running DorisCluster panics the CN controller. Sync calls ClearResources only when spec.cnSpec is nil, but ClearResources then reads dcr.Spec.CnSpec.AutoScalingPolicy. The operator recovers the panic

Steps to reproduce:

1. Apply a DorisCluster with feSpec, beSpec and cnSpec, and wait until status.cnStatus is populated.
2. Delete the cnSpec block from the CR
3. On every requeue, the operator log shows invalid memory address or nil pointer dereference

BE's ClearResources checks Spec.BeSpec == nil before it touches the spec, and broker does the same with BrokerSpec. FE's. CN was the only controller that read its spec without a nil check, on a code path that runs only when that spec is nil.

[Al-assad]

Thanks for the fix!
The nil guard looks good. Could we use a fake client for these regression tests instead of starting envtest in init()? This would avoid adding an API server dependency to all tests in the CN package and keep the tests simpler. There are existing examples using fake.NewClientBuilder() in the repository.

[Al-assad]

LGTM