Protocol Buffer imports not recognized in Intellij

Question

I am attempting to import one protocol buffer message into another, but the imports are not recognized. As long as I don't try to import one protobuf into another, the protobuf code is generated (in java), the code compiles and runs as expected.

I'm using:

• Intellij Idea 2020 v1.3 Unlimited Edition
• Protobuf Editor plugin: jvolkman/intellij-protobuf-editor (April 2020)
• Gradle

My gradle build file looks like this:

plugins {
    id 'java'
    id 'com.google.protobuf' version "0.8.8"
}

group 'tech.tablesaw'
version '1.0-SNAPSHOT'

sourceCompatibility = 9.0

def grpcVersion = '1.30.1' // CURRENT_GRPC_VERSION
def protobufVersion = '3.12.0'
def protocVersion = protobufVersion

repositories {
    mavenCentral()
}

test {
    useJUnitPlatform()
}

dependencies {
    implementation "io.grpc:grpc-protobuf:${grpcVersion}"
    implementation "io.grpc:grpc-stub:${grpcVersion}"
    compileOnly "org.apache.tomcat:annotations-api:6.0.53"

    // advanced - need this for JsonFormat
    implementation "com.google.protobuf:protobuf-java-util:${protobufVersion}"

    runtimeOnly "io.grpc:grpc-netty-shaded:${grpcVersion}"
    testImplementation "io.grpc:grpc-testing:${grpcVersion}"

    compile group: 'tech.tablesaw', name: 'tablesaw-core', version: '0.38.1'
    testCompile group: 'org.junit.jupiter', name: 'junit-jupiter-engine', version: '5.6.2'
    testImplementation "org.mockito:mockito-core:2.28.2"
}

protobuf {
    protoc { artifact = "com.google.protobuf:protoc:${protocVersion}" }
    plugins {
        grpc { artifact = "io.grpc:protoc-gen-grpc-java:${grpcVersion}" }
    }
    generateProtoTasks {
        all()*.plugins { grpc {} }
    }
}

// Inform IDEs like IntelliJ IDEA, Eclipse or NetBeans about the generated code.
sourceSets {
    main {
        java {
            srcDirs 'build/generated/source/proto/main/grpc'
            srcDirs 'build/generated/source/proto/main/java'
        }
    }
}

task TablesawServer(type: CreateStartScripts) {
    mainClassName = 'tech.tablesaw.service.TableServiceServer'
    applicationName = 'tablesaw-table-server'
    outputDir = new File(project.buildDir, 'tmp')
}

task TablesawClient(type: CreateStartScripts) {
    mainClassName = 'tech.tablesaw.service.TableServiceClient'
    applicationName = 'tablesaw-table-client'
    outputDir = new File(project.buildDir, 'tmp')
}

and my gradle info looks like this:

------------------------------------------------------------
Gradle 5.1.1
------------------------------------------------------------

Build time:   2019-01-10 23:05:02 UTC
Revision:     3c9abb645fb83932c44e8610642393ad62116807

Kotlin DSL:   1.1.1
Kotlin:       1.3.11
Groovy:       2.5.4
Ant:          Apache Ant(TM) version 1.9.13 compiled on July 10 2018
JVM:          9.0.4 (Oracle Corporation 9.0.4+11)
OS:           Mac OS X 10.13.5 x86_64

Here is an example protobuf. the import of the column_type.proto fails.

syntax = "proto3";

package tech.tablesaw.service.common;

import "tech/tablesaw/service/common/column_type.proto";

option java_multiple_files = true;
option java_package = "tech.tablesaw.service.common";
option java_outer_classname = "ColumnMetaProto";
option objc_class_prefix = "TSW";

// Proto file describing column metadata message.

// A column metadata object
message ColumnMetadata {

  string name = 1;
  int32 size = 2;
  ColumnTypeEnum.ColumnType column_type = 3;
}

And here is the file i'm trying to import:

syntax = "proto3";

package tech.tablesaw.service.common;

option java_multiple_files = true;
option java_package = "tech.tablesaw.service.common";
option java_outer_classname = "ColumnTypeEnum";
option objc_class_prefix = "TSW";

enum ColumnType {
  SHORT = 0;
  INTEGER = 1;
  LONG = 2;
  FLOAT = 3;
  BOOLEAN = 4;
  STRING = 5;
  DOUBLE = 6;
  LOCAL_DATE = 7;
  LOCAL_TIME = 8;
  LOCAL_DATE_TIME = 9;
  INSTANT = 10;
  TEXT = 11;
  SKIP = 12;
}

Finally, here's where the protobufs sit in the file system.

src > main > java
           > proto > tech > tablesaw > service > common > column_metadata.proto
                                                        > column_type.proto

Answer 1

Take a look at the readme which describes how to add additional paths.

By default, intellij-protobuf-editor uses the project's configured source roots as protobuf import paths. If this isn't correct, you can override these paths in Settings > Languages & Frameworks > Protocol Buffers. Uncheck "Configure automatically" and add whichever paths you need. In your case, you'd add .../src/main/java/proto (where ... means whatever your project's base path is).

Answer 2

There was an answer to this question in the comments for another question: Error using import in .proto file

If you're using IntelliJ IDEA, go to Preferences -> Protobuf Support and add the path to your .proto file. This would resolve the error.

In a more modern version of Intellij, this is done in the plugin intellij-protobuf-editor. I added the path to the root of my proto source folder and all was well

Answer 3

Want to describe what helped me, since I did not find an answer here. My steps are for Maven, but I think it will be pretty much the same for Gradle.

1. Check that you have this plugin

      <plugin>
        <groupId>org.xolstice.maven.plugins</groupId>
        <artifactId>protobuf-maven-plugin</artifactId>
        <version>0.6.1</version>

        <configuration>
          <protocArtifact>com.google.protobuf:protoc:3.12.2:exe:${os.detected.classifier}</protocArtifact>
        </configuration>

        <executions>
          <execution>
            <goals>
              <goal>compile</goal>
              <goal>test-compile</goal>
            </goals>
          </execution>
        </executions>
      </plugin>

2. Check that you have this extension in your build section

  <build>
    <extensions>
      <extension>
        <groupId>kr.motd.maven</groupId>
        <artifactId>os-maven-plugin</artifactId>
        <version>1.6.1</version>
      </extension>
    </extensions>
    ....

3. Run this maven goal

mvn protobuf:compile

Answer 4

If you are using protobuf-gradle-plugin, you need to apply the idea plugin. After applying it, everything works like a charm. From their readme

apply plugin: 'idea'

clean {
    delete protobuf.generatedFilesBaseDir
}

idea {
    module {
        // proto files and generated Java files are automatically added as
        // source dirs.
        // If you have additional sources, add them here:
        sourceDirs += file("/path/to/other/sources");
    }
}