strict_deps_mode = error complains about dependencies that aren't referenced

[evis]

I tried to turn on strict_deps_mode = "error" in my scala_toolchain(), but it complains about dependencies that aren't used directly in my Scala code.

BUILD:

proto_library(
    name = "model_proto",
    srcs = ["model.proto"],
    visibility = ["//visibility:public"],
)

java_proto_library(
    name = "model_java_proto",
    visibility = ["//visibility:public"],
    deps = [
        ":model_proto",
    ],
)

scala_library(
    name = "scala_class",
    srcs = ["ScalaClass.scala"],
    visibility = ["//deps-mode:__subpackages__"],
    deps = [":model_java_proto"],
)

model.proto:

syntax = "proto3";

package deps_mode;

enum ProtoEnum {
  UNKNOWN = 0;
  KNOWN = 1;
}

ScalaClass.scala:

package deps_mode

case class ScalaClass(value: Model.ProtoEnum)

Expected bazel build result: success (it builds with strict_deps_mode = "off").

Actual bazel build result: fails with

error: Target '@@com_google_protobuf//java/core:lite_runtime_only' is used but isn't explicitly declared, please add it to the deps.
You can use the following buildozer command:
buildozer 'add deps @@com_google_protobuf//java/core:lite_runtime_only' //deps-mode:scala_class
error: Target '@@com_google_protobuf//java/core:core' is used but isn't explicitly declared, please add it to the deps.
You can use the following buildozer command:
buildozer 'add deps @@com_google_protobuf//java/core:core' //deps-mode:scala_class
2 errors
Build failed
java.lang.RuntimeException: Build failed
        at io.bazel.rulesscala.scalac.ScalacInvoker.invokeCompiler(ScalacInvoker.java:55)
        at io.bazel.rulesscala.scalac.ScalacWorker.compileScalaSources(ScalacWorker.java:253)
        at io.bazel.rulesscala.scalac.ScalacWorker.work(ScalacWorker.java:69)
        at io.bazel.rulesscala.worker.Worker.persistentWorkerMain(Worker.java:86)
        at io.bazel.rulesscala.worker.Worker.workerMain(Worker.java:39)
        at io.bazel.rulesscala.scalac.ScalacWorker.main(ScalacWorker.java:33)

It's kind of surprising, since protobuf//java isn't used explicitly in my Scala code, it's used transitively via ProtoEnum.

Moreover, if I run all of given buildozer commands, then build fails again:

in scala_library rule //deps-mode:scala_class: target '@@com_google_protobuf//java/core:lite_runtime_only' is not visible from target '//deps-mode:scala_class'. Check the visibility declaration of the former target if you think the dependency is legitimate

Although, if I just do buildozer 'add deps @@com_google_protobuf//java/core:core' //deps-mode:scala_class, then build succeeds. But I'd like to avoid adding this dependency everywhere.

[evis]

Also, strict_deps_mode = error sometimes suggests to add proto_library() dependencies, instead of java_proto_library() dependencies. Couldn't create MVCE yet, though.

[liucijus]

Hi, @evis! Thanks for reporting. Could you create a small repo to reproduce your problem?

Regarding java_proto_library deps being incorrectly reported - it's a known issue. It happens because the archive is stamped with incorrect target label from the aspect. The similar issue for scala_proto_library is here for more info: https://github.com/bazelbuild/rules_scala/issues/1234#issuecomment-791628830

[evis]

Regarding java_proto_library deps being incorrectly reported - it's a known issue

Thanks for your link, found https://github.com/bazelbuild/bazel/issues/4990 here

Could you create a small repo to reproduce your problem?

Yes, I'll try