Failed to build Kotlin code with proto models using Bazel - kotlin

Question

I'm trying to use compiled proto models into my kotlin code. Project is managed by bazel. So I reproduce problem with simple "HelloWorld" project.
WORKSPACE
load("#bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
RULES_KOTLIN_VERSION = "9051eb053f9c958440603d557316a6e9fda14687"
http_archive(
name = "io_bazel_rules_kotlin",
sha256 = "c36e71eec84c0e17dd098143a9d93d5720e81b4db32bceaf2daf939252352727",
strip_prefix = "rules_kotlin-%s" % RULES_KOTLIN_VERSION,
url = "https://github.com/bazelbuild/rules_kotlin/archive/%s.tar.gz" % RULES_KOTLIN_VERSION,
)
load("#io_bazel_rules_kotlin//kotlin:kotlin.bzl", "kotlin_repositories", "kt_register_toolchains")
kotlin_repositories()
kt_register_toolchains()
http_archive(
name = "com_google_protobuf",
strip_prefix = "protobuf-master",
urls = ["https://github.com/protocolbuffers/protobuf/archive/master.zip"],
)
load("#com_google_protobuf//:protobuf_deps.bzl", "protobuf_deps")
protobuf_deps()
BUILD
load("#io_bazel_rules_kotlin//kotlin:kotlin.bzl", "kt_jvm_library")
load("#rules_java//java:defs.bzl", "java_binary", "java_lite_proto_library", "java_proto_library")
load("#rules_proto//proto:defs.bzl", "proto_library")
package(default_visibility = ["//visibility:public"])
proto_library(
name = "clicklocation_proto",
srcs = ["ClickLocation.proto"],
)
java_proto_library(
name = "clicklocation_java_lite_proto",
deps = [":clicklocation_proto"],
)
kt_jvm_library(
name = "app_lib",
srcs = ["Main.kt"],
deps = [":clicklocation_java_lite_proto"]
)
java_binary(
name = "myapp",
main_class = "MyApp",
runtime_deps = [":app_lib"],
)
Proto file
syntax = "proto2";
package objectrecognition;
option java_package = "com.kshmax.objectrecognition.proto";
option java_outer_classname = "ClickLocationProtos";
message ClickLocation {
required float x = 1;
required float y = 2;
}
Main.kt
import com.kshmax.objectrecognition.proto.ClickLocationProtos
class MyApp {
companion object {
#JvmStatic
fun main(args: Array<String>) {
val location = ClickLocationProtos.ClickLocation.newBuilder()
location.x = 0.1f
location.y = 0.2f
location.build()
}
}
}
I have done it as described in protocolbuffers/protobuf repository examples .
But I got an error:
error: supertypes of the following classes cannot be resolved. Please
make sure you have the required dependencies in the classpath: class
com.kshmax.objectrecognition.proto.ClickLocationProtos.ClickLocation,
unresolved supertypes: com.google.protobuf.GeneratedMessageV3 class
com.kshmax.objectrecognition.proto.ClickLocationProtos.ClickLocationOrBuilder,
unresolved supertypes: com.google.protobuf.MessageOrBuilder class
com.kshmax.objectrecognition.proto.ClickLocationProtos.ClickLocation.Builder,
unresolved supertypes: com.google.protobuf.GeneratedMessageV3.Builder
What am I doing wrong?

Answer 1

The code that uses protobuf needs to depend on the protobuf library itself.
In theory, this could be exported by the rule, but since it doesn't work, I would add a dep on protobuf directly, similarly to BuildEventServiceTest
deps= [
"#com_google_protobuf//:protobuf_java",
"my_foo_java_proto",
]
or java_lite_proto_library / "#com_google_protobuf//:protobuf_java_lite" where the remote repository was defined in the WORKSPACE as
http_archive(
name = "com_google_protobuf",
patch_args = ["-p1"],
patches = ["#io_bazel//third_party/protobuf:3.11.3.patch"],
patch_cmds = EXPORT_WORKSPACE_IN_BUILD_FILE,
patch_cmds_win = EXPORT_WORKSPACE_IN_BUILD_FILE_WIN,
sha256 = "cf754718b0aa945b00550ed7962ddc167167bd922b842199eeb6505e6f344852",
strip_prefix = "protobuf-3.11.3",
urls = [
"https://mirror.bazel.build/github.com/protocolbuffers/protobuf/archive/v3.11.3.tar.gz",
"https://github.com/protocolbuffers/protobuf/archive/v3.11.3.tar.gz",
],
)
(I'm not sure you need the patch, and there might be a more recent version; look at the example)