[protoc-gen-policy] oneof type is not properly generates policy hepler

[kvivek1115]

Describe the bug

• proto3 oneof type not fully supported by the protoc-gen-policy tool.
• seems it is calling oneof message attributes directly instead it should get inverted to the interface.

To Reproduce

Steps to reproduce the behavior:

• Add oneof message types in sample requests.
  eg.

message UpdateOrg {
    string id = 1;
    oneof test {
        string name = 2;
        string admin_key = 3;
    };
    string admin_user = 4;
    string server_id = 5;
    repeated string projects = 6;
}

• hit compile_go_protobuf_component api.
• wired & implement all request gateway functions.
• try rebuild components/automate-gateway
• it raises any error:

# github.com/chef/automate/api/external/infra_proxy
/src/api/external/infra_proxy/infra_proxy.pb.policy.go:166:14: m.Name undefined (type *request.UpdateOrg has no field or method Name)
/src/api/external/infra_proxy/infra_proxy.pb.policy.go:168:14: m.AdminKey undefined (type *request.UpdateOrg has no field or method AdminKey)
   automate-gateway: Build time: 0m3s
   automate-gateway: Exiting on error

Expected behavior

• it should simply rebuild the automate-gateway.

Versions (please complete the following information):

• OS: ubuntu
• Automate: latest master

Additional context

Add any other context about the problem here.

• policy code generated for this type:

policy.MapMethodTo("/chef.automate.api.infra_proxy.InfraProxy/UpdateOrg", "infra:infraServers:{server_id}:orgs:{id}", "infra:infraServers:update", "PUT", "/api/v0/infra/servers/{server_id}/orgs/{id}", func(unexpandedResource string, input interface{}) string {
		if m, ok := input.(*request.UpdateOrg); ok {
			return policy.ExpandParameterizedResource(unexpandedResource, func(want string) string {
				switch want {
				case "id":
					return m.Id
				case "name":
					return m.Name
				case "admin_key":
					return m.AdminKey
				case "admin_user":
					return m.AdminUser
				case "server_id":
					return m.ServerId
				default:
					return ""
				}
			})
		}
		return ""

it should be something like

policy.MapMethodTo("/chef.automate.api.infra_proxy.InfraProxy/UpdateOrg", "infra:infraServers:{server_id}:orgs:{id}", "infra:infraServers:update", "PUT", "/api/v0/infra/servers/{server_id}/orgs/{id}", func(unexpandedResource string, input interface{}) string {
		if m, ok := input.(*request.UpdateOrg); ok {
			return policy.ExpandParameterizedResource(unexpandedResource, func(want string) string {
				switch want {
				case "id":
					return m.Id
				case "name":
					return m.GetTest().(*request.UpdateOrg_Name).Name
				case "admin_key":
					return m.GetTest().(*request.UpdateOrg_AdminKey).AdminKey
				case "admin_user":
					return m.AdminUser
				case "server_id":
					return m.ServerId
				default:
					return ""
				}
			})
		}
		return ""
	})

[srenatus]

From discussion in slack, this isn't blocking anything right now. But it is a genuine bug we should look into.

I believe that since we don't know which oneof field will be set (it wouldn't be in a oneof if we did), they cannot be used for action/resource mapping anyways. So, ignoring them would be the easy way out here.