Bazel throws an error when loading `rust_proto_library`

[schoppmp]

What version of protobuf and what language are you using?
Version: 33.0-rc1
Language: Rust

What operating system (Linux, Windows, ...) and version?

Debian 6.12.35-1rodete1-amd64

What runtime / compiler are you using (e.g., python version or gcc version)

bazel 8.4.2

What did you do?

Write load("@protobuf//rust:defs.bzl", "rust_proto_library") in a BUILD file

What did you expect to see

rust_proto_library should be available in dependent projects

What did you see instead?

Bazel throws the following error:
Unable to find package for @@[unknown repo 'rules_rust' requested from @@protobuf+ (did you mean 'rules_cc'?)]//rust:defs.bzl: The repository '@@[unknown repo 'rules_rust' requested from @@protobuf+ (did you mean 'rules_cc'?)]' could not be resolved: No repository visible as '@rules_rust' from repository '@@protobuf+'.

Anything else we should know about your project / environment

The reason seems to be that rules_rust is a dev_dependency of protobuf, not a regular dependency. Adding it as a dependency of my project does not help, since Bazel loads protobuf before rules_rust.

[esrauchg]

The context here is that the bazel folks have been concerned with the size of our dependencies under bzlmod, since we support a number of languages and most users only use a small number of those it makes the deps bloated. Rust was held back as a dev dependency to try to avoid that.

Bazel added a "nodep" feature which was intended to give a path forward for having an all-languages repo and then smaller per-language ones that aren't necessarily pulled in (bazelbuild/bazel#25214).

I'm not clear if we could just already use nodep on rules_rust today to be able to locally move forward here without bloating the deps for non-Rust users, or if we do need to make a protobuf-rust package just to unblock this.

[esrauchg]

I have opened bazelbuild/bazel#27264 with the bazel team to discuss a possible different way forward that would let us cleanly support this, we will see how that discussion goes before making a plan for this case.

[meteorcloudy]

if we do need to make a protobuf-rust package just to unblock this.

Some experiment at #23987