fix cluster labels update conflict.

[morvencao]

fix cluster labels update conflict:

E1122 13:49:38.188870       1 base_controller.go:270] "AddOnFeatureDiscoveryController" controller failed to sync "ocm-controlplane-1-mc-4/work-manager", err: Operation cannot be fulfilled on managedclusters.cluster.open-cluster-management.io "ocm-controlplane-1-mc-4": the object has been modified; please apply your changes to the latest version and try again
E1122 13:49:45.423603       1 base_controller.go:270] "AddOnFeatureDiscoveryController" controller failed to sync "ocm-controlplane-1-mc-3/governance-policy-framework", err: Operation cannot be fulfilled on managedclusters.cluster.open-cluster-management.io "ocm-controlplane-1-mc-3": the object has been modified; please apply your changes to the latest version and try again
E1122 13:49:45.438568       1 base_controller.go:270] "AddOnFeatureDiscoveryController" controller failed to sync "ocm-controlplane-1-mc-1/config-policy-controller", err: Operation cannot be fulfilled on managedclusters.cluster.open-cluster-management.io "ocm-controlplane-1-mc-1": the object has been modified; please apply your changes to the latest version and try again
E1122 13:49:45.451226       1 base_controller.go:270] "AddOnFeatureDiscoveryController" controller failed to sync "ocm-controlplane-1-mc-3/config-policy-controller", err: Operation cannot be fulfilled on managedclusters.cluster.open-cluster-management.io "ocm-controlplane-1-mc-3": the object has been modified; please apply your changes to the latest version and try again
E1122 13:49:45.460923       1 base_controller.go:270] "AddOnFeatureDiscoveryController" controller failed to sync "ocm-controlplane-1-mc-1/config-policy-controller", err: Operation cannot be fulfilled on managedclusters.cluster.open-cluster-management.io "ocm-controlplane-1-mc-1": the object has been modified; please apply your changes to the latest version and try again
E1122 13:49:45.477055       1 base_controller.go:270] "AddOnFeatureDiscoveryController" controller failed to sync "ocm-controlplane-1-mc-1/governance-policy-framework", err: Operation cannot be fulfilled on managedclusters.cluster.open-cluster-management.io "ocm-controlplane-1-mc-1": the object has been modified; please apply your changes to the latest version and try again
E1122 13:49:45.488734       1 base_controller.go:270] "AddOnFeatureDiscoveryController" controller failed to sync "ocm-controlplane-1-mc-3", err: Operation cannot be fulfilled on managedclusters.cluster.open-cluster-management.io "ocm-controlplane-1-mc-3": the object has been modified; please apply your changes to the latest version and try again
E1122 13:49:45.503787       1 base_controller.go:270] "AddOnFeatureDiscoveryController" controller failed to sync "ocm-controlplane-1-mc-1/governance-policy-framework", err: Operation cannot be fulfilled on managedclusters.cluster.open-cluster-management.io "ocm-controlplane-1-mc-1": the object has been modified; please apply your changes to the latest version and try again
E1122 13:49:45.511774       1 base_controller.go:270] "AddOnFeatureDiscoveryController" controller failed to sync "ocm-controlplane-1-mc-3", err: Operation cannot be fulfilled on managedclusters.cluster.open-cluster-management.io "ocm-controlplane-1-mc-3": the object has been modified; please apply your changes to the latest version and try again

Signed-off-by: morvencao lcao@redhat.com

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[morvencao]

/hold

[morvencao]

is the integration test failure relevant?

[morvencao]

/hold cancel

[skeeey]

it seems not, restart the test to have a try

[morvencao]

@qiujian16 Another look? all comments addressed except the one set to nil for label key, because labels is known type(map[string]string), set value to nil, it will complain:

pkg/hub/addon/discovery_controller.go:144:17: cannot use nil as string value in assignment
pkg/hub/addon/discovery_controller.go:148:17: cannot use nil as string value in assignment
pkg/hub/addon/discovery_controller.go:219:23: cannot use nil as string value in assignment
pkg/hub/addon/discovery_controller.go:234:23: cannot use nil as string value in assignment

[qiujian16]

you cannot set nil in map[string]string, but you can do it in map[string]interface{}. The patch you generate should be based on a map[string]interface{}.

[morvencao]

Any benefit to use map[string]interface{} instead of map[string]string? In labels update case, the labels field is known type, and the JSON encoding can also generate patch bytes based on map[string]string type. We can convert map[string]string to map[string]interface{}, but that will also make it more complicated, especially we need to check whether labels are actually updated before launch patch request. I tried to use map[string]interface{}, it is more complicated and the UT cases are also need to updated accordingly.

[qiujian16]

you can delete a key with map[string]interface{}