Problem: an error is reported when proto unmarshal is used, and the following information is prompted:

cannot use promoRule (variable of type *db.PromotionRuleSet) as protoreflect.ProtoMessage value in argument to proto.Unmarshal: missing method ProtoReflect (compile)

Solution:
Import package from

"google.golang.org/protobuf/proto"

Change to

"github.com/golang/protobuf/proto"