another step, that nobody asked for, could be to add multiple systems whispering dialects of enums to each other over the wire https://protobuf.dev/programming

another step, that nobody asked for, could be to add multiple systems whispering dialects of enums to each other over the wire https://protobuf.dev/programming-guides/enum/ https://protobuf.dev/programming-guides/enum/ > Enums have two distinct flavors (open and closed). They behave identically except in their handling of unknown values. > The distinction between open and closed can be encapsulated in a single question: > > What happens when a program parses binary data that contains field 1 [defined in the proto used by that program] with the value 2 [where 2 is a value not defined for the enum for field 1 used by that program]? > Open enums will parse the value 2 and store it directly in the field. Accessor will report the field as being set and will return something that represents 2 > Closed enums will parse the value 2 and store it in the message’s unknown field set. Accessors will report the field as being unset and will return the enum’s default value > The following specifies the behavior of conformant implementations for protobuf > When a proto2 file imports an enum defined in a proto2 file, that enum should be treated as closed. > When a proto3 file imports an enum defined in a proto3 file, that enum should be treated as open. > When a proto3 file imports an enum defined in a proto2 file, the protoc compiler will produce an error. > When a proto2 file imports an enum defined in a proto3 file, that enum should be treated as open > Known Issues > All known [C++, C#, Java, Kotlin, Go, JSPB, Ruby, Dart] releases are out of conformance > [PHP, Python >= 4.22.0, Objective C >= 22.0, Swift] is conformant.