Flag --incompatible_disable_starlark_host_transitions will break stardoc in Bazel 7.0

[keertk]

Incompatible flag --incompatible_disable_starlark_host_transitions will be enabled by default in the next major release (Bazel 7.0), thus breaking stardoc. Please migrate to fix this and unblock the flip of this flag.

The flag is documented here: bazelbuild/bazel#17032.

Please check the following CI builds for build and test results:

• MacOS OpenJDK 11
• Ubuntu 18.04 OpenJDK 11
• Ubuntu 20.04 OpenJDK 11
• Windows OpenJDK 11

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If you have any questions, please file an issue in https://github.com/bazelbuild/continuous-integration.

[sgowroji]

Hi Team, Gentle ping , Can you share any significant update on this issue. Thanks!

[tetromino]

We are not using host transitions in Stardoc itself - but it's used by many of our deps (skylib, rules_license, rules_jvm_external, rules_cc).

We should check whether those projects have releases which work with --incompatible_disable_starlark_host_transitions (for skylib e.g. we need to update to 1.4.1).

[tetromino]

We're blocked by Bazel itself using host transitions in third_party/grpc/build_defs.bzl :)

ERROR: Traceback (most recent call last):
	File "/private/var/tmp/_bazel_arostovtsev/4db74ff3612d0bdc1259d9a6e5cd2136/external/io_bazel/third_party/grpc/build_defs.bzl", line 64, column 30, in <toplevel>
		"_protoc": attr.label(
Error in label: 'cfg = "host"' is deprecated and should no longer be used. Please use 'cfg = "exec"' instead.
ERROR: /private/var/tmp/_bazel_arostovtsev/4db74ff3612d0bdc1259d9a6e5cd2136/external/io_bazel/src/main/java/com/google/devtools/build/lib/collect/nestedset/BUILD:16:13: error loading package '@io_bazel//src/main/protobuf': initialization of module 'third_party/grpc/build_defs.bzl' failed and referenced by '@io_bazel//src/main/java/com/google/devtools/build/lib/collect/nestedset:nestedset'

[tetromino]

Steps to fix:

• bump bazel_skylib to 1.4.1 or newer - fixed in f8fab82
• switch to cfg = "exec" in bazel's own third_party/grpc rules - waiting for Switch third_party/grpc from deprecated cfg = "host" to cfg = "exec" bazel#19192
• bump rules_jvm_external to 5.0 or newer (probably 5.2, since that's what io_bazel is on at the moment)