Use separate configuration for extracting included proto from dependencies

gradle/wrapper/gradle-wrapper.properties

@@ -2,4 +2,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.6-bin.zip

src/main/groovy/com/google/protobuf/gradle/ProtobufPlugin.groovy

@@ -35,7 +35,9 @@ import org.gradle.api.GradleException
 import org.gradle.api.Plugin
 import org.gradle.api.Project
 import org.gradle.api.Task
+import org.gradle.api.artifacts.Configuration
 import org.gradle.api.attributes.Attribute
+import org.gradle.api.attributes.LibraryElements
 import org.gradle.api.file.FileCollection
 import org.gradle.api.file.SourceDirectorySet
 import org.gradle.api.internal.file.DefaultSourceDirectorySet
@@ -54,6 +56,7 @@ class ProtobufPlugin implements Plugin<Project> {
     // any one of these plugins should be sufficient to proceed with applying this plugin
     private static final List<String> PREREQ_PLUGIN_OPTIONS = [
             'java',
+            'java-library',
             'com.android.application',
             'com.android.feature',
             'com.android.library',
@@ -135,7 +138,7 @@ class ProtobufPlugin implements Plugin<Project> {
 
         addSourceSetExtensions()
         getSourceSets().all { sourceSet ->
-          createConfiguration(sourceSet.name)
+          createConfigurations(sourceSet.name)
         }
         project.afterEvaluate {
           // The Android variants are only available at this point.
@@ -158,18 +161,41 @@ class ProtobufPlugin implements Plugin<Project> {
     }
 
     /**
-     * Creates a configuration if necessary for a source set so that the build
+     * Creates configurations if necessary for a source set so that the build
      * author can configure dependencies for it.
      */
-    private void  createConfiguration(String sourceSetName) {
-      String configName = Utils.getConfigName(sourceSetName, 'protobuf')
-      if (project.configurations.findByName(configName) == null) {
-        project.configurations.create(configName) {
+    private void  createConfigurations(String sourceSetName) {
+      String protobufConfigName = Utils.getConfigName(sourceSetName, 'protobuf')
+      if (project.configurations.findByName(protobufConfigName) == null) {
+        project.configurations.create(protobufConfigName) {
           visible = false
           transitive = true
           extendsFrom = []
         }
       }
+
+      // Create a 'compileProtoPath' configuration that extends compilation configurations
+      // as a bucket of dependencies with resources attribute. This works around 'java-library'
+      // plugin not exposing resources to consumers for compilation.
+      // Some Android sourceSets (more precisely, variants) do not have compilation configurations,
+      // they do not contain compilation dependencies, so they would not depend on any upstream
+      // proto files.
+      String compileProtoConfigName = Utils.getConfigName(sourceSetName, 'compileProtoPath')
+      Configuration compileConfig =
+              project.configurations.findByName(Utils.getConfigName(sourceSetName, 'compileOnly'))
+      Configuration implementationConfig =
+              project.configurations.findByName(Utils.getConfigName(sourceSetName, 'implementation'))
+      if (compileConfig && implementationConfig &&
+              project.configurations.findByName(compileProtoConfigName) == null) {
+        project.configurations.create(compileProtoConfigName) {
+          visible = false
+          transitive = true
+          extendsFrom = [compileConfig, implementationConfig]
+          canBeConsumed = false
+        }.getAttributes().attribute(
+                LibraryElements.LIBRARY_ELEMENTS_ATTRIBUTE,
+                project.getObjects().named(LibraryElements, LibraryElements.RESOURCES))
+      }
     }
 
     /**
@@ -364,7 +390,7 @@ class ProtobufPlugin implements Plugin<Project> {
           description = "Extracts proto files from compile dependencies for includes"
           destDir = getExtractedIncludeProtosDir(sourceSetOrVariantName) as File
           inputFiles.from(compileClasspathConfiguration
-            ?: project.configurations[Utils.getConfigName(sourceSetOrVariantName, 'compile')])
+            ?: project.configurations[Utils.getConfigName(sourceSetOrVariantName, 'compileProtoPath')])
 
           // TL; DR: Make protos in 'test' sourceSet able to import protos from the 'main'
           // sourceSet.  Sub-configurations, e.g., 'testCompile' that extends 'compile', don't

src/test/groovy/com/google/protobuf/gradle/ProtobufJavaPluginTest.groovy

@@ -200,6 +200,62 @@ class ProtobufJavaPluginTest extends Specification {
     gradleVersion << GRADLE_VERSIONS
   }
 
+  @Unroll
+  void "testProjectJavaLibrary should be successfully executed (java-only as a library) [gradle #gradleVersion]"() {
+    given: "project from testProjectJavaLibrary"
+    File projectDir = ProtobufPluginTestHelper.projectBuilder('testProjectJavaLibrary')
+            .copyDirs('testProjectBase', 'testProjectJavaLibrary')
+            .build()
+
+    when: "build is invoked"
+    BuildResult result = GradleRunner.create()
+            .withProjectDir(projectDir)
+            .withArguments('build', '--stacktrace')
+            .withGradleVersion(gradleVersion)
+            .forwardStdOutput(new OutputStreamWriter(System.out))
+            .forwardStdError(new OutputStreamWriter(System.err))
+            .withDebug(true)
+            .build()
+
+    then: "it succeed"
+    result.task(":build").outcome == TaskOutcome.SUCCESS
+    ProtobufPluginTestHelper.verifyProjectDir(projectDir)
+
+    where:
+    gradleVersion << GRADLE_VERSIONS
+  }
+
+  @Unroll
+  void "testProjectDependentApp should be successfully executed [gradle #gradleVersion]"() {
+    given: "project from testProject & testProjectDependent"
+    File testProjectStaging = ProtobufPluginTestHelper.projectBuilder('testProjectJavaLibrary')
+            .copyDirs('testProjectBase', 'testProjectJavaLibrary')
+            .build()
+    File testProjectDependentStaging = ProtobufPluginTestHelper.projectBuilder('testProjectDependentApp')
+            .copyDirs('testProjectDependentApp')
+            .build()
+
+    File mainProjectDir = ProtobufPluginTestHelper.projectBuilder('testProjectDependentAppMain')
+            .copySubProjects(testProjectStaging, testProjectDependentStaging)
+            .build()
+
+    when: "build is invoked"
+    BuildResult result = GradleRunner.create()
+            .withProjectDir(mainProjectDir)
+            .withArguments('testProjectDependentApp:build', '--stacktrace')
+            .withGradleVersion(gradleVersion)
+            .forwardStdOutput(new OutputStreamWriter(System.out))
+            .forwardStdError(new OutputStreamWriter(System.err))
+            .withDebug(true)
+            .build()
+
+    then: "it succeed"
+    result.task(":testProjectDependentApp:build").outcome == TaskOutcome.SUCCESS
+
+    where:
+    gradleVersion << GRADLE_VERSIONS
+  }
+
   @Unroll
   void "testProjectCustomProtoDir should be successfully executed [gradle #gradleVersion]"() {
     given: "project from testProjectCustomProtoDir"

testProjectDependentApp/build.gradle

@@ -0,0 +1,31 @@
+// A project that depends on another project and a published artifact, both of
+// which include proto files. The included proto files are added to the
+// --proto_path argument of protoc, so that the protos from this project can
+// import them. However, these imported proto files will not be compiled in
+// this project, since they have already been compiled in their own projects.
+
+apply plugin: 'java'
+apply plugin: 'com.google.protobuf'
+
+repositories {
+    maven { url "https://plugins.gradle.org/m2/" }
+}
+
+dependencies {
+    implementation 'com.google.protobuf:protobuf-java:3.0.0'
+    implementation project(':testProjectJavaLibrary')
+
+    testImplementation 'junit:junit:4.12'
+}
+
+protobuf.protoc {
+  artifact = 'com.google.protobuf:protoc:3.0.0'
+}
+
+test.doLast {
+  // This project has compiled only one proto file, despite that it imports
+  // other proto files from dependencies.
+  def generatedFiles = project.fileTree(protobuf.generatedFilesBaseDir + "/main")
+  File onlyGeneratedFile = generatedFiles.singleFile
+  assert 'Dependent.java' == onlyGeneratedFile.name
+}

testProjectDependentApp/settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'testProjectDependentApp'

testProjectDependentApp/src/main/proto/dependent.proto

@@ -0,0 +1,14 @@
+syntax = "proto3";
+
+package dependent;
+
+// From testProject/src/main/proto
+import "ws/antonov/protobuf/test/test.proto";
+
+// From protobuf-java artifact
+import "google/protobuf/any.proto";
+
+message WrapperMessage {
+  ws.antonov.protobuf.test.Item item = 1;
+  google.protobuf.Any any = 2;
+}

testProjectDependentApp/src/test/java/DependentTest.java

@@ -0,0 +1,19 @@
+import static org.junit.Assert.assertSame;
+
+import org.junit.Test;
+
+public class DependentTest {
+
+  @Test public void testProtos() {
+    dependent.Dependent.WrapperMessage message =
+        dependent.Dependent.WrapperMessage.newBuilder()
+            .setItem(ws.antonov.protobuf.test.Test.Item.getDefaultInstance())
+            .setAny(com.google.protobuf.Any.getDefaultInstance())
+            .build();
+    assertSame(ws.antonov.protobuf.test.Test.Item.getDefaultInstance(),
+        message.getItem());
+    Dependent2.TestWrapperMessage testMessage =
+        Dependent2.TestWrapperMessage.newBuilder()
+            .setM(message).build();
+  }
+}

testProjectDependentApp/src/test/proto/dependent2.proto

@@ -0,0 +1,8 @@
+syntax = "proto3";
+
+// From the 'main' sourceSet
+import "dependent.proto";
+
+message TestWrapperMessage {
+  dependent.WrapperMessage m = 1;
+}

testProjectJavaLibrary/build.gradle

@@ -0,0 +1,5 @@
+// This build is not a complete project, but is used to generate a project.
+// See: ProtobufPluginTestHelper.groovy
+apply plugin: 'java-library'
+apply plugin: 'idea'
+apply from: 'build_base.gradle'

testProjectJavaLibrary/settings.gradle

@@ -0,0 +1 @@
+rootProject.name = 'testProjectJavaLibrary'

testProjectJavaLibrary/src/main/java/Foo.java

@@ -0,0 +1,30 @@
+import com.google.protobuf.MessageLite;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Foo {
+  public static List<MessageLite> getDefaultInstances() {
+    ArrayList<MessageLite> list = new ArrayList<MessageLite>();
+    // from src/main/proto/test.proto
+    list.add(ws.antonov.protobuf.test.Test.TestMessage.getDefaultInstance());
+    list.add(ws.antonov.protobuf.test.Test.AnotherMessage.getDefaultInstance());
+    list.add(ws.antonov.protobuf.test.Test.Item.getDefaultInstance());
+    list.add(ws.antonov.protobuf.test.Test.DataMap.getDefaultInstance());
+    // from src/main/proto/sample.proto (java_multiple_files == true, thus no outter class)
+    list.add(com.example.tutorial.Msg.getDefaultInstance());
+    list.add(com.example.tutorial.SecondMsg.getDefaultInstance());
+    // from lib/protos.tar.gz/stuff.proto
+    list.add(Stuff.Blah.getDefaultInstance());
+    // from ext/more.proto
+    list.add(More.MoreMsg.getDefaultInstance());
+    list.add(More.Foo.getDefaultInstance());
+    // from ext/test1.proto
+    list.add(test1.Test1.Test1Msg.getDefaultInstance());
+    // from ext/ext1/test1.proto
+    list.add(ext1.Ext1Test1.Ext1Test1Msg.getDefaultInstance());
+    // from ext/test2.proto
+    list.add(test2.Test2.Test2Msg.getDefaultInstance());
+    return list;
+  }
+}

testProjectJavaLibrary/src/test/java/FooTest.java

@@ -0,0 +1,25 @@
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class FooTest {
+  @org.junit.Test
+  public void testMainProtos() {
+    assertEquals(12, Foo.getDefaultInstances().size());
+  }
+
+  @org.junit.Test
+  public void testTestProtos() {
+    // from src/test/proto/test.proto
+    Test.MsgTest.getDefaultInstance();
+    // from lib/protos-test.tar.gz
+    test.Stuff.BlahTest.getDefaultInstance();
+  }
+
+  @org.junit.Test
+  public void testGrpc() {
+    // from src/grpc/proto/
+    assertTrue(com.google.protobuf.GeneratedMessageV3.class.isAssignableFrom(
+        io.grpc.testing.integration.Messages.SimpleRequest.class));
+    assertTrue(Object.class.isAssignableFrom(io.grpc.testing.integration.TestServiceGrpc.class));
+  }
+}