protoc: import in service.proto not resolved

I have a project where the service definition is in a separate file form the message definition. protoc doesn't like this:

Execution failed for task ':generateProto'.
> protoc: stdout: . stderr: IAscIndication.proto:11:13: "AscIndication" is not defined.
  IAscIndication.proto:11:37: "AscResponse" is not defined.

(protoc is called from gradle).

Is this something one shouldn't do or a problem in our setup or a bug in protoc (3.19.4)? It works when I combine both files in one.

The files in question:

IAscIndication.proto

syntax = "proto3";

import "Asc.proto";

package com.tyntec.hades.v1;
option java_multiple_files = true;
option java_package = "com.tyntec.hades.grpc";

service IAscIndication
{
    rpc Asc(AscIndication) returns (AscResponse) {}
}

Asc.proto

syntax = "proto3";

import "BaseTypes.proto";

package tyntec.hades.v1;
option java_multiple_files = true;
option java_package = "com.tyntec.hades.grpc";

message AscRequest
{
    SignalOutbound      meta            = 1;
    AscRequestData      data            = 2;
}

message AscIndication
{
    SignalInbound       meta            = 1;
    AscRequestData      data            = 2;
}

And here is the cmdline and error when called from bash:

> /home/martinsc/.gradle/caches/modules-2/files-2.1/com.google.protobuf/protoc/3.19.4/99ed7588824cb00e0db4f1b215e7d4c69d00e74b/protoc-3.19.4-linux-x86_64.exe -I/home/martinsc/java/mt/acheron/src/main/proto -I/home/martinsc/java/mt/acheron/build/extracted-protos/main -I/home/martinsc/java/mt/acheron/build/extracted-include-protos/main --java_out=/home/martinsc/java/mt/acheron/src/generated/main/java --plugin=protoc-gen-grpc=/home/martinsc/.gradle/caches/modules-2/files-2.1/io.grpc/protoc-gen-grpc-java/1.44.1/5d42eec0c997038e3a131dea05ad9f5be37992cb/protoc-gen-grpc-java-1.44.1-linux-x86_64.exe --grpc_out=/home/martinsc/java/mt/acheron/src/generated/main/grpc /home/martinsc/java/mt/acheron/src/main/proto/Asc.proto /home/martinsc/java/mt/acheron/src/main/proto/BaseTypes.proto /home/martinsc/java/mt/acheron/src/main/proto/Error.proto /home/martinsc/java/mt/acheron/src/main/proto/IAscIndication.proto
IAscIndication.proto:11:13: "AscIndication" is not defined.
IAscIndication.proto:11:37: "AscResponse" is not defined.

System is Ubuntu 20.4.

Solution

This is due to the package that doesn't match (probably a typo). In order to include another file they either need to be in the same package or you need to use the -I option in protoc.

So in your case you probably need to change you Asc.proto package to :

package com.tyntec.hades.v1;

or change your IAscIndication.proto one to:

package tyntec.hades.v1;

If you do not want to change the packages, you have two possibilities:

try to run protoc like this:

protoc -I. [your_other_options] *.proto

use the fully qualified name in the rpc endpoint

rpc Asc(tyntec.hades.v1.AscIndication) returns (tyntec.hades.v1.AscResponse) {}