Protobuf v29.2 build fails with bazelisk

[pkwarren]

What version of protobuf and what language are you using?
Version: v29.2
Language: All

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

What runtime / compiler are you using (e.g., python version or gcc version)
clang 16.0.0

What did you do?
Steps to reproduce the behavior:

1. Run bazelisk build '//:protoc_lib'

What did you expect to see
Build should download bazel (if needed) and compile the protobuf library.

What did you see instead?

$ bazelisk build //:protoc_lib
2024/12/19 09:34:32 Downloading https://releases.bazel.build/8.0.0/release/bazel-8.0.0-darwin-arm64...
2024/12/19 09:34:32 Skipping basic authentication for releases.bazel.build because no credentials found in /Users/pkw/.netrc
Downloading: 56 MB out of 56 MB (100%) 
Extracting Bazel installation...
Starting local Bazel server and connecting to it...
INFO: Invocation ID: 89a9cc3b-037e-49c2-b34f-47a21bfb0c8c
ERROR: Error computing the main repository mapping: error loading package 'external': Both --enable_bzlmod and --enable_workspace are disabled, but one of them must be enabled to fetch external dependencies.
Computing main repo mapping: 

It would be nice if protobuf checked in a .bazelversion with a known good version of Bazel to use for compilation, as without it the build attempts to use the latest version of Bazel. For reference, gRPC checks one in https://github.com/grpc/grpc/blob/master/.bazelversion. After creating this file, compilation succeeds with bazelisk.

Anything else we should know about your project / environment
n/a