Unable to depend on WKTs with Bazel 0.29

[steeve]

When running Bazel 0.29.0rc6 + rules_swift master, the following rule fails:

swift_proto_library(
    name = "duration_swift",
    deps = ["@com_google_protobuf//:duration_proto"],
)

$ bazel build //:duration_swift --verbose_failures
ERROR: /private/var/tmp/_bazel_steeve/435e7d592a4c50f40fe16990c7f36232/external/com_google_protobuf/BUILD:288:2: Generating Swift sources for @com_google_protobuf//:duration_proto failed (Exit 1) mkdir_and_run failed: error executing command
  (cd /private/var/tmp/_bazel_steeve/435e7d592a4c50f40fe16990c7f36232/sandbox/darwin-sandbox/232/execroot/co_znly_protodefs && \
  exec env - \
  bazel-out/host/bin/external/build_bazel_rules_swift/tools/mkdir_and_run/mkdir_and_run bazel-out/darwin-fastbuild/bin/external/com_google_protobuf/duration_proto.protoc_gen_pb_swift bazel-out/host/bin/external/com_google_protobuf/protoc '--plugin=protoc-gen-swift=bazel-out/host/bin/external/com_github_apple_swift_protobuf/ProtoCompilerPlugin' '--swift_out=bazel-out/darwin-fastbuild/bin/external/com_google_protobuf/duration_proto.protoc_gen_pb_swift' '--swift_opt=FileNaming=FullPath' '--swift_opt=Visibility=Public' '--swift_opt=ProtoPathModuleMappings=bazel-out/darwin-fastbuild/bin/external/com_google_protobuf/<target @com_google_protobuf/:duration_proto>.protoc_gen_swift_modules.asciipb' --descriptor_set_in bazel-out/darwin-fastbuild/bin/external/com_google_protobuf/duration_proto-descriptor-set.proto.bin _virtual_imports/duration_proto/google/protobuf/duration.proto)
Execution platform: @bazel_tools//platforms:host_platform

Use --sandbox_debug to see verbose messages from the sandbox
_virtual_imports/duration_proto/google/protobuf/duration.proto: No such file or directory
Target //tileserver:duration_swift failed to build

Building with Bazel 0.28.1 works. Leading me to think bazelbuild/bazel#7157 may be the culprit.

[steeve]

Apparently proto rules need updating: grpc/grpc#19860