bazel query not working in my repo after depending on @protobuf//:protobuf_python

[dirkboye]

What version of protobuf and what language are you using?
v31.1

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

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

What did you do?
Minimal example:

MODULE.bazel

bazel_dep(name = "protobuf", version = "31.1")

BUILD.bazel

genrule(
    name = "foo",
    # srcs = ["@protobuf//:protobuf_java"],
    srcs = ["@protobuf//:protobuf_python"],
    outs = ["bar.txt"],
    cmd = "ls > \"$@\"",
    tools = [],
)

Then run bazel query 'deps(//...)'
This works with @protobuf//:protobuf_java as a dependency but I immediately get an error with @protobuf//:protobuf_python as a dependency.

What did you expect to see
$ bazel query 'deps(//...)'
-> a list of my dependencies.

What did you see instead?
$ bazel query 'deps(//...)'
ERROR: Evaluation of query "deps(//...)" failed: preloading transitive closure failed: error loading package '@@protobuf+//python/dist': Unable to find package for @@[unknown repo 'protobuf_pip_deps' requested from @@protobuf+]//:requirements.bzl: The repository '@@[unknown repo 'protobuf_pip_deps' requested from @@protobuf+]' could not be resolved: No repository visible as '@protobuf_pip_deps' from repository '@@protobuf+'.

[zhangskz]

This is a known issue since python targets using our system python headers (e.g. //python/dist - targets for to build our pypi release artifacts, protobuf_python with :use_fast_cpp_protos) are not Bzlmod compatible yet. We are actively working on changing these to get python headers from hermetic python provided by rules_python to get this working via Bzlmod -- apologies for the inconvenience!

protobuf_python should not actually hit this / require these python headers by default but is likely hitting this for bazel query due to select case that does:

protobuf/python/build_targets.bzl

Line 35 in 4708cf5

":google/protobuf/pyext/_message.so",

bazel cquery should avoid this by handling selects for protobuf//:protobuf_python correctly.
Alternatively, this should also work fine when using WORKSPACE.