In this CL we're adding the barebones infrastructure to generate Rust proto messages using UPB as a backend. The API is what we call a V0, not yet production-quality, not yet rigorously designed, just something to enable parallel work.
The interesting part of switching backend between UPB and C++ will come in a followup.
PiperOrigin-RevId: 517089760
The internal design is consistent with other <lang>_proto_library rules. rust_proto_library attaches rust_proto_library_aspect on its `deps` attribute. The aspect traverses the dependency, and when it visits proto_library (detected by ProtoInfo provider) it registers 2 actions:
1) to run protoc with Rust backend to emit gencode
2) to compile the gencode using Rustc
Action (2) gets the Rust proto runtime as an input as well.
Coming in a followup is support and test coverage for proto_library.deps.
PiperOrigin-RevId: 514521285
This code is experimental and should not be expected to emit working code, and callers are liable to break without warning.
It is being released now so that development can occur in the open, but users should not expect this to be supported any time soon.
PiperOrigin-RevId: 508095929
Marcel Hlopko
Augie Fackler
Jakob Buchgraber
Protobuf Team Bot
Mike Kruskal