Using well_known_protos in C++

[seungryulchoisc]

Hi, I am building C++ code with protos using bazel. I'd like to use any.proto, one of @com_github_google_protobuf//:well_known_protos, but when I build it, I am getting the following error:
Import "google/protobuf/any.proto" was not found or had errors.

My cc_proto_library entry is:

cc_proto_library(
    name = "b_proto_cc",
    protos = [ "a/b.proto", ],
    imports = [
        "external/com_github_google_protobuf/src/",
    ],
    deps = [
        "@com_github_google_protobuf//:cc_wkt_protos",
    ],
)

Thanks.

[pcj]

Due to sandboxing, just declaring imports = ["external/com_github_google_protobuf/src/"] may not be enough. You can confirm if this is the problem by building with --spawn_strategy=standalone.

In that case, you will also need to tell bazel that the any.proto file needs to be available in the sandbox when the rule is executed. You can do this with the includes attribute, naming the :well_known_protos filegroup that has any.proto in it:

cc_proto_library(
    name = "b_proto_cc",
    protos = [ "a/b.proto", ],
    imports = [
        "external/com_github_google_protobuf/src/",
    ],
    includes = [
        "@com_github_google_protobuf//:well_known_protos",
    ],
    deps = [
        "@com_github_google_protobuf//:cc_wkt_protos",
    ],
)

In a future version of rules_protobuf I think it should be preferable to auto-detect the presence of :cc_wkt_protos (or similar) and just add in the import and include statements implicitly.

If this resolves the problem go ahead and close out the issue. If not, can you post the contents of a/b.proto?

[seungryulchoisc]

I added includes lines, but it didn't work either.

I am using CC and Go, so I prefer pubref but I can try cc_proto_library in google/protobuf in this case. Thanks anyways.

[pcj]

OK, but I am interested in not leaving it unsolved. Any chance you can post your proto file? If you have a repo that repoduces it even better.

[seungryulchoisc]

Thanks for your help. One way that I found is adding ../../. If you know a better solution, please let me know. Here are my files.

home/WORKSPACE has

git_repository(
    name = "org_pubref_rules_protobuf",
    remote = "https://github.com/pubref/rules_protobuf.git",
    tag = "v0.7.1",
)   

load("@org_pubref_rules_protobuf//cpp:rules.bzl", "cpp_proto_repositories")
cpp_proto_repositories()

new_local_repository(
    name = "c",
    build_file = "BUILD.c",
    path = __workspace_dir__ + "/c/proto",
)

home/BUILD.c has

cc_proto_library(
    name = "b_proto_cc",
    protos = [ "a/b.proto", ],
    imports = [
        "../../external/com_github_google_protobuf/src/",
    ],  
    deps = [
        "@com_github_google_protobuf//:cc_wkt_protos",
    ],
)

home/c/proto/a/b.proto has

syntax = "proto3";
import "google/protobuf/any.proto";
  
message d {
  repeated google.protobuf.Any e = 1;
}