Also forward the exported_plugins of the rules in the deps of an

android_library rule when the android_library is being used as a forwarding rule
(i.e., has no sources).

RELNOTES: When used as a forwarding rule (i.e., has no sources), android_library
will also forward any exported_plugins in its dependencies.

--
MOS_MIGRATED_REVID=105787789

src/main/java/com/google/devtools/build/lib/rules/android/AndroidCommon.java

@@ -55,6 +55,7 @@
 import com.google.devtools.build.lib.rules.java.JavaCompilationArtifacts;
 import com.google.devtools.build.lib.rules.java.JavaCompilationHelper;
 import com.google.devtools.build.lib.rules.java.JavaNativeLibraryProvider;
+import com.google.devtools.build.lib.rules.java.JavaPluginInfoProvider;
 import com.google.devtools.build.lib.rules.java.JavaRuleOutputJarsProvider;
 import com.google.devtools.build.lib.rules.java.JavaRuntimeJarProvider;
 import com.google.devtools.build.lib.rules.java.JavaSemantics;
@@ -88,6 +89,7 @@ public class AndroidCommon {
   private NestedSet<Artifact> transitiveSourceJars = NestedSetBuilder.emptySet(Order.STABLE_ORDER);
   private JavaCompilationArgs javaCompilationArgs = JavaCompilationArgs.EMPTY_ARGS;
   private JavaCompilationArgs recursiveJavaCompilationArgs = JavaCompilationArgs.EMPTY_ARGS;
+  private JavaPluginInfoProvider transitiveJavaPluginInfoProvider = JavaPluginInfoProvider.EMPTY;
   private JackCompilationHelper jackCompilationHelper;
   private Artifact classJar;
   private Artifact iJar;
@@ -566,8 +568,16 @@ private void initJava(
     topLevelSourceJars = ImmutableList.of(srcJar);
     transitiveSourceJars = javaCommon.collectTransitiveSourceJars(srcJar);
 
+    boolean hasSources = attributes.hasSourceFiles() || attributes.hasSourceJars();
+
+    if (!hasSources) {
+      // If this android rule has no sources, then it's a forwarding rule, so also forward
+      // any exported java plugins from its deps.
+      this.transitiveJavaPluginInfoProvider = JavaPluginInfoProvider.merge(
+           javaCommon.getPluginInfoProvidersForAttribute("deps", Mode.TARGET));
+    }
+
     if (collectJavaCompilationArgs) {
-      boolean hasSources = attributes.hasSourceFiles() || attributes.hasSourceJars();
       this.javaCompilationArgs =
           collectJavaCompilationArgs(ruleContext, exportDeps, asNeverLink, hasSources);
       this.recursiveJavaCompilationArgs = collectJavaCompilationArgs(
@@ -616,6 +626,7 @@ public RuleConfiguredTargetBuilder addTransitiveInfoProviders(
             asNeverLink
                 ? jackCompilationHelper.compileAsNeverlinkLibrary()
                 : jackCompilationHelper.compileAsLibrary())
+        .add(JavaPluginInfoProvider.class, transitiveJavaPluginInfoProvider)
         .addOutputGroup(
             OutputGroupProvider.HIDDEN_TOP_LEVEL, collectHiddenTopLevelArtifacts(ruleContext))
         .addOutputGroup(JavaSemantics.SOURCE_JARS_OUTPUT_GROUP, transitiveSourceJars);

src/main/java/com/google/devtools/build/lib/rules/java/JavaCommon.java

@@ -665,7 +665,7 @@ private ImmutableList<JavaPluginInfoProvider> collectPlugins() {
     return ImmutableList.copyOf(result);
   }
 
-  Iterable<JavaPluginInfoProvider> getPluginInfoProvidersForAttribute(String attribute,
+  public Iterable<JavaPluginInfoProvider> getPluginInfoProvidersForAttribute(String attribute,
       Mode mode) {
     if (ruleContext.attributes().has(attribute, BuildType.LABEL_LIST)) {
       return ruleContext.getPrerequisites(attribute, mode, JavaPluginInfoProvider.class);

src/main/java/com/google/devtools/build/lib/rules/java/JavaLibrary.java

@@ -162,19 +162,9 @@ public RuleConfiguredTargetBuilder init(RuleContext ruleContext, final JavaCommo
     NestedSet<LinkerInput> transitiveJavaNativeLibraries =
         common.collectTransitiveJavaNativeLibraries();
 
-    ImmutableList<String> exportedProcessorClasses = ImmutableList.of();
-    NestedSet<Artifact> exportedProcessorClasspath =
-        NestedSetBuilder.emptySet(Order.NAIVE_LINK_ORDER);
-    ImmutableList.Builder<String> processorClasses = ImmutableList.builder();
-    NestedSetBuilder<Artifact> processorClasspath = NestedSetBuilder.naiveLinkOrder();
-    for (JavaPluginInfoProvider provider : Iterables.concat(
-        common.getPluginInfoProvidersForAttribute("exported_plugins", Mode.HOST),
-        common.getPluginInfoProvidersForAttribute("exports", Mode.TARGET))) {
-      processorClasses.addAll(provider.getProcessorClasses());
-      processorClasspath.addTransitive(provider.getProcessorClasspath());
-    }
-    exportedProcessorClasses = processorClasses.build();
-    exportedProcessorClasspath = processorClasspath.build();
+    JavaPluginInfoProvider javaPluginInfoProvider = JavaPluginInfoProvider.merge(Iterables.concat(
+          common.getPluginInfoProvidersForAttribute("exported_plugins", Mode.HOST),
+          common.getPluginInfoProvidersForAttribute("exports", Mode.TARGET)));
 
     CcLinkParamsStore ccLinkParamsStore = new CcLinkParamsStore() {
       @Override
@@ -249,8 +239,7 @@ protected void collect(CcLinkParams.Builder builder, boolean linkingStatically,
         .add(JavaSourceJarsProvider.class, new JavaSourceJarsProvider(
             transitiveSourceJars, ImmutableList.of(srcJar)))
         // TODO(bazel-team): this should only happen for java_plugin
-        .add(JavaPluginInfoProvider.class, new JavaPluginInfoProvider(
-            exportedProcessorClasses, exportedProcessorClasspath))
+        .add(JavaPluginInfoProvider.class, javaPluginInfoProvider)
         .add(ProguardSpecProvider.class, new ProguardSpecProvider(proguardSpecs))
         .addOutputGroup(JavaSemantics.SOURCE_JARS_OUTPUT_GROUP, transitiveSourceJars)
         .addOutputGroup(OutputGroupProvider.HIDDEN_TOP_LEVEL, proguardSpecs);

src/main/java/com/google/devtools/build/lib/rules/java/JavaPluginInfoProvider.java

@@ -18,14 +18,34 @@
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.analysis.TransitiveInfoProvider;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
+import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
+import com.google.devtools.build.lib.collect.nestedset.Order;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 
 /**
  * Provider for users of Java plugins.
  */
 @Immutable
 public final class JavaPluginInfoProvider implements TransitiveInfoProvider {
+
+  public static final JavaPluginInfoProvider EMPTY =
+      new JavaPluginInfoProvider(
+          ImmutableList.<String>of(),
+          NestedSetBuilder.<Artifact>emptySet(Order.STABLE_ORDER));
 
+  public static JavaPluginInfoProvider merge(Iterable<JavaPluginInfoProvider> providers) {
+
+    ImmutableList.Builder<String> processorClasses = ImmutableList.builder();
+    NestedSetBuilder<Artifact> processorClasspath = NestedSetBuilder.naiveLinkOrder();
+
+    for (JavaPluginInfoProvider provider : providers) {
+      processorClasses.addAll(provider.getProcessorClasses());
+      processorClasspath.addTransitive(provider.getProcessorClasspath());
+    }
+
+    return new JavaPluginInfoProvider(processorClasses.build(), processorClasspath.build());
+  }
+
   private final ImmutableList<String> processorClasses;
   private final NestedSet<Artifact> processorClasspath;