On the other side, if they wrote multiple projects and never noticed the behavior, how bad can it be ?
It would be interesting if that extra header optimized the processing a lot, pushing other libraries to have it as an option.
Many projects will choose a standard encoding to give them language independence, but start by using the same language and libraries on both ends of the pipe. Therefore,you might not notice the library is incompatible until quite late in a project's development when you try to replace a component with a seemingly compatible, alternative implementation.
https://github.com/protocolbuffers/protobuf/tree/main/confor...
Seems like a good idea for protocols in general to have an official test suite, as a way to address this problem
Framing appears higher up the stack, as an RPC transport, or structured storage like the recordio format referenced by the author. The article sounds like the client expected application/protobuf but the server sent application/custom-protobuf-framing.