Cannot generate protobuf for map[string][]string

[jianzhangbjz]

Hey guys,

I added a new type(type TopologyMap map[ResourceName][]string) in pkg/api/v1/types.go file.
And execute ./hack/update-generated-protobuf.sh to update pkg/api/v1/generated.proto file, but I got map<string, string> gTopology = 11;, a bit confusing, details as the below:

pkg/api/v1/types.go

type TopologyMap map[ResourceName][]string

        // +optional
        GTopology TopologyMap `json:"gTopology,omitempty" protobuf:"bytes,11,opt,name=gTopology,casttype=TopologyMap,castkey=ResourceName"`

pkg/api/v1/generated.proto

// +optional
map<string, string> gTopology = 11;

Why the value of map is string? Or something else I missed?
And then execute make quick-release command, got errors as the below:

    plugin/cmd/kube-scheduler
# k8s.io/kubernetes/pkg/api/v1
pkg/api/v1/generated.pb.go:4734: arguments to copy have different element types: []byte and []string
pkg/api/v1/generated.pb.go:27251: cannot use mapvalue (type string) as type []string in assignment
!!! [0518 07:37:46] Call tree:
...
make: *** [quick-release] Error 1

[jianzhangbjz]

Refer to issue #27259 and PR #28788 fixed this problem. I have to define a new type for []string and add optional, like this:

type TopologyMap map[ResourceName]TopologyValue

// TopologyValue masks the value so protobuf can generate
// +protobuf.nullable=true
// +protobuf.options.(gogoproto.goproto_stringer)=false
type TopologyValue []string

func (t TopologyValue) String() string {
        return fmt.Sprintf("%v", []string(t))
}

So, close it.