Re:Revisiting Apple Notes (6): The Protobuf
by cryptonector on Monday September 21, 2020 @03:04PM
(#24547135)
This is called "extensibility".
In ASN.1 people were doing the same thing unofficially in the mid-80s, then explicit support was added in the form of "extensibility markers".
There's nothing new in protobufs.
EDIT: I should add that the non-TLV encoding rules for ASN.1 all support extensibility. Also, there are good engineering practices and security reasons why one should want explicit documentation of what structures/enums/choices/typeranges are expected to be extensible. Relying on decoders to ignore unexpected bits is not a sound practice.
In ASN.1 people were doing the same thing unofficially in the mid-80s, then explicit support was added in the form of "extensibility markers".
There's nothing new in protobufs.
EDIT: I should add that the non-TLV encoding rules for ASN.1 all support extensibility. Also, there are good engineering practices and security reasons why one should want explicit documentation of what structures/enums/choices/typeranges are expected to be extensible. Relying on decoders to ignore unexpected bits is not a sound practice.