Summary

Hi team. First of all thank you for all what you're doing. I recently stumbled upon an issue which looks like regression. After PR 4439 landed, some Go targets in the our configuration end up in different “pure” modes depending on whether a C/C++ toolchain is resolvable for that specific target. This leads to a mode mismatch during go_proto_library analysis. I would appreciate if you could take a look on it

Use case

I'm not sure exactly how to reproduce the issue, but roughly our usecase look like this:

proto_library(
    name = "example_proto",
    srcs = ["example.proto"],
)

go_proto_library(
    name = "example_go_proto",
    importpath = "example.org/project/example",
    proto = ":example_proto",
)

go_binary(
    name = "binary",
    srcs = ["main.go"],
    deps = [":example_go_proto"],
)

Environment

• rules_go version: master (commit after PR 4439)
• Host/Execution platform: macOS
• Target platform: linux/arm64

Error

ERROR: /.../BUILD.bazel:11:17: in go_proto_library rule //golang/proto:example_go_proto: 
Traceback (most recent call last):
        File "/private/var/tmp/_bazel_dbieliaiev/8c62e38a32f8dc70f07523f1ae120a02/external/io_bazel_rules_go/proto/def.bzl", line 166, column 29, in _go_proto_library_impl
                archive = go.archive(go, go_info)
        File "/private/var/tmp/_bazel_dbieliaiev/8c62e38a32f8dc70f07523f1ae120a02/external/io_bazel_rules_go/go/private/actions/archive.bzl", line 86, column 17, in emit_archive
                fail("Archive mode does not match {} is {} expected {}".format(a.data.label, mode_string(a.source.mode), mode_string(go.mode)))
Error in fail: Archive mode does not match @com_github_golang_protobuf//proto:proto is linux_arm64_stripped expected linux_arm64_pure_stripped
ERROR: /.../BUILD.bazel:11:17: Analysis of target '//golang/proto:example_go_proto' failed

The failure is reproducible on master.

Why this looks like a regression introduced by PR 4439

The behavior change appears tied to go/private/context.bzl logic introduced/modified in PR 4439. Specifically this branch:

• go/private/context.bzl:L507–L508

If I remove this lines:

if getattr(attr, "_cc_toolchain", None) and CPP_TOOLCHAIN_TYPE in ctx.toolchains:
    cgo_context_info = cgo_context_data_impl(ctx)

The build succeeds.

Additional context: why we are on master

• We require features from >= 0.56.0, specifically PR 4397.
• All released versions versions >= 0.56.0 still exhibits issue 3945.
• The fix landed in PR 4432, which has not been released yet.
• Therefore I pinned to a master commit but found out this regression.