Add ProtoInfo constructor to Starlark

src/main/java/com/google/devtools/build/lib/rules/proto/BUILD

@@ -50,6 +50,8 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/vfs",
         "//src/main/java/com/google/devtools/build/lib/vfs:pathfragment",
         "//src/main/java/com/google/devtools/common/options",
+        "//src/main/java/net/starlark/java/eval",
+        "//src/main/java/net/starlark/java/syntax",
         "//third_party:auto_value",
         "//third_party:guava",
         "//third_party:jsr305",

src/main/java/com/google/devtools/build/lib/rules/proto/BazelProtoLibraryRule.java

@@ -19,13 +19,15 @@
 import static com.google.devtools.build.lib.packages.BuildType.LABEL_LIST;
 import static com.google.devtools.build.lib.packages.Type.STRING;
 
+import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.analysis.BaseRuleClasses;
 import com.google.devtools.build.lib.analysis.RuleDefinition;
 import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
 import com.google.devtools.build.lib.analysis.config.ExecutionTransitionFactory;
 import com.google.devtools.build.lib.cmdline.Label;
 import com.google.devtools.build.lib.packages.Attribute;
 import com.google.devtools.build.lib.packages.RuleClass;
+import com.google.devtools.build.lib.packages.StarlarkProviderIdentifier;
 import com.google.devtools.build.lib.util.FileType;
 
 /**
@@ -61,7 +63,12 @@ public RuleClass build(RuleClass.Builder builder, final RuleDefinitionEnvironmen
         <code>proto_library</code> targets.
         It may not depend on language-specific libraries.
         <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
-        .override(attr("deps", LABEL_LIST).allowedRuleClasses("proto_library").allowedFileTypes())
+        .override(attr("deps", LABEL_LIST)
+            .allowedFileTypes()
+            .mandatoryProvidersList(
+                ImmutableList.of(
+                    ImmutableList.of(
+                        StarlarkProviderIdentifier.forKey(ProtoInfo.PROVIDER.getKey())))))
         /* <!-- #BLAZE_RULE(proto_library).ATTRIBUTE(srcs) -->
         The list of <code>.proto</code> and <code>.protodevel</code> files that are
         processed to create the target. This is usually a non empty list. One usecase
@@ -77,7 +84,12 @@ public RuleClass build(RuleClass.Builder builder, final RuleDefinitionEnvironmen
         List of proto_library targets that can be referenced via "import public" in the proto
         source.
         <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
-        .add(attr("exports", LABEL_LIST).allowedRuleClasses("proto_library").allowedFileTypes())
+        .add(attr("exports", LABEL_LIST)
+            .allowedFileTypes()
+            .mandatoryProvidersList(
+                ImmutableList.of(
+                    ImmutableList.of(
+                        StarlarkProviderIdentifier.forKey(ProtoInfo.PROVIDER.getKey())))))
         /* <!-- #BLAZE_RULE(proto_library).ATTRIBUTE(strip_import_prefix) -->
         The prefix to strip from the paths of the .proto files in this rule.
 
@@ -101,7 +113,7 @@ public RuleClass build(RuleClass.Builder builder, final RuleDefinitionEnvironmen
         prefix is added.
         <!-- #END_BLAZE_RULE.ATTRIBUTE --> */
         .add(attr("import_prefix", STRING))
-        .advertiseStarlarkProvider(ProtoInfo.PROVIDER.id())
+        .advertiseStarlarkProvider(StarlarkProviderIdentifier.forKey(ProtoInfo.PROVIDER.getKey()))
         .build();
   }
 

src/main/java/com/google/devtools/build/lib/rules/proto/ProtoCommon.java

@@ -36,6 +36,7 @@
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
 import com.google.devtools.build.lib.vfs.PathFragment;
 import javax.annotation.Nullable;
+import net.starlark.java.syntax.Location;
 
 /**
  * Utility functions for proto_library and proto aspect implementations.
@@ -107,9 +108,9 @@ private static NestedSet<ProtoSource> computeExportedProtos(
   }
 
   private static NestedSet<ProtoSource> computeTransitiveProtoSources(
-      ImmutableList<ProtoInfo> protoDeps, Library library) {
+      ImmutableList<ProtoInfo> protoDeps, ImmutableList<ProtoSource> protoSources) {
     NestedSetBuilder<ProtoSource> result = NestedSetBuilder.naiveLinkOrder();
-    result.addAll(library.getSources());
+    result.addAll(protoSources);
     for (ProtoInfo dep : protoDeps) {
       result.addTransitive(dep.getTransitiveSources());
     }
@@ -387,7 +388,31 @@ public static ProtoInfo createProtoInfo(
 
     ImmutableList<ProtoSource> directSources = library.getSources();
     PathFragment directProtoSourceRoot = library.getSourceRoot();
-    NestedSet<ProtoSource> transitiveSources = computeTransitiveProtoSources(deps, library);
+    Artifact directDescriptorSet =
+        ruleContext.getGenfilesArtifact(
+            ruleContext.getLabel().getName() + "-descriptor-set.proto.bin");
+
+    return createProtoInfo(
+        originalDirectProtoSources,
+        directSources,
+        deps,
+        exports,
+        directProtoSourceRoot,
+        directDescriptorSet,
+        Location.BUILTIN);
+  }
+
+  public static ProtoInfo createProtoInfo(
+      ImmutableList<Artifact> originalDirectProtoSources,
+      ImmutableList<ProtoSource> directSources,
+      ImmutableList<ProtoInfo> deps,
+      ImmutableList<ProtoInfo> exports,
+      PathFragment directProtoSourceRoot,
+      Artifact directDescriptorSet,
+      Location location) {
+
+    NestedSet<ProtoSource> transitiveSources =
+        computeTransitiveProtoSources(deps, directSources);
     NestedSet<Artifact> transitiveProtoSources =
         computeTransitiveProtoSourceArtifacts(directSources, deps);
     NestedSet<Artifact> transitiveOriginalProtoSources =
@@ -396,9 +421,6 @@ public static ProtoInfo createProtoInfo(
         computeTransitiveProtoSourceRoots(deps, directProtoSourceRoot.getSafePathString());
     NestedSet<Artifact> strictImportableProtosForDependents =
         computeStrictImportableProtosForDependents(directSources, deps);
-    Artifact directDescriptorSet =
-        ruleContext.getGenfilesArtifact(
-            ruleContext.getLabel().getName() + "-descriptor-set.proto.bin");
     NestedSet<Artifact> transitiveDescriptorSets =
         computeTransitiveDescriptorSets(directDescriptorSet, deps);
 
@@ -420,7 +442,8 @@ public static ProtoInfo createProtoInfo(
         transitiveDescriptorSets,
         exportedSources,
         strictImportableSources,
-        publicImportSources);
+        publicImportSources,
+        location);
   }
 
   public static Runfiles.Builder createDataRunfilesProvider(

src/main/java/com/google/devtools/build/lib/rules/proto/ProtoInfo.java

@@ -22,9 +22,16 @@
 import com.google.devtools.build.lib.packages.BuiltinProvider;
 import com.google.devtools.build.lib.packages.NativeInfo;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
+import com.google.devtools.build.lib.starlarkbuildapi.FileApi;
 import com.google.devtools.build.lib.starlarkbuildapi.ProtoInfoApi;
 import com.google.devtools.build.lib.starlarkbuildapi.proto.ProtoBootstrap;
 import com.google.devtools.build.lib.vfs.PathFragment;
+import java.util.List;
+import net.starlark.java.eval.EvalException;
+import net.starlark.java.eval.Sequence;
+import net.starlark.java.eval.Starlark;
+import net.starlark.java.eval.StarlarkThread;
+import net.starlark.java.syntax.Location;
 
 /**
  * Configured target classes that implement this class can contribute .proto files to the
@@ -33,13 +40,6 @@
 @Immutable
 @AutoCodec
 public final class ProtoInfo extends NativeInfo implements ProtoInfoApi<Artifact> {
-  /** Provider class for {@link ProtoInfo} objects. */
-  public static class ProtoInfoProvider extends BuiltinProvider<ProtoInfo>
-      implements ProtoInfoProviderApi {
-    public ProtoInfoProvider() {
-      super(ProtoBootstrap.PROTO_INFO_STARLARK_NAME, ProtoInfo.class);
-    }
-  }
 
   public static final ProtoInfoProvider PROVIDER = new ProtoInfoProvider();
 
@@ -93,7 +93,9 @@ public ProtoInfo(
       // Layering checks.
       NestedSet<ProtoSource> exportedSources,
       NestedSet<ProtoSource> strictImportableSources,
-      NestedSet<ProtoSource> publicImportSources) {
+      NestedSet<ProtoSource> publicImportSources,
+      Location creationLocation) {
+    super(creationLocation);
     this.directSources = directSources;
     this.directProtoSources = extractProtoSources(directSources);
     this.originalDirectProtoSources = extractOriginalProtoSources(directSources);
@@ -263,4 +265,63 @@ public NestedSet<ProtoSource> getStrictImportableSources() {
   NestedSet<ProtoSource> getPublicImportSources() {
     return publicImportSources;
   }
+
+  /** Provider class for {@link ProtoInfo} objects. */
+  public static class ProtoInfoProvider extends BuiltinProvider<ProtoInfo>
+      implements ProtoInfoProviderApi {
+    private ProtoInfoProvider() {
+      super(ProtoBootstrap.PROTO_INFO_STARLARK_NAME, ProtoInfo.class);
+    }
+
+    private void checkSequenceOfProtoInfo(Sequence<?> seq, String field) throws EvalException {
+      for (Object v : seq) {
+        if (!(v instanceof ProtoInfo)) {
+          throw Starlark.errorf("Expected 'sequence of ProtoInfo' for '%s', found element of type '%s'", field, Starlark.type(v));
+        }
+      }
+    }
+
+    @Override
+    @SuppressWarnings({"unchecked"})
+    public ProtoInfo protoInfo(
+        String protoSourceRootApi,
+        FileApi descriptorSetApi,
+        Sequence<?> sourcesApi,
+        Sequence<?> depsApi,
+        Sequence<?> exportsApi,
+        StarlarkThread thread)
+        throws EvalException {
+
+      checkSequenceOfProtoInfo(depsApi, "deps");
+      checkSequenceOfProtoInfo(exportsApi, "exports");
+
+      Artifact directDescriptorSet = (Artifact) descriptorSetApi;
+
+      List<Artifact> directSourcesList = Sequence.cast(sourcesApi, Artifact.class, "sources");
+      ImmutableList<Artifact> originalDirectProtoSources = ImmutableList.copyOf(directSourcesList);
+
+      ImmutableList.Builder<ProtoSource> sourcesBuilder = ImmutableList.builder();
+      for(Artifact src: directSourcesList) {
+        sourcesBuilder.add(new ProtoSource(src, PathFragment.create(protoSourceRootApi)));
+      }
+      ImmutableList<ProtoSource> sources = sourcesBuilder.build();
+
+      List<ProtoInfo> depsList = Sequence.cast(depsApi, ProtoInfo.class, "deps");
+      ImmutableList<ProtoInfo> deps = ImmutableList.copyOf(depsList);
+
+      List<ProtoInfo> exportsList = Sequence.cast(exportsApi, ProtoInfo.class, "exports");
+      ImmutableList<ProtoInfo> exports = ImmutableList.copyOf(exportsList);
+
+      PathFragment protoSourceRoot = PathFragment.create(protoSourceRootApi);
+
+      return ProtoCommon.createProtoInfo(
+          originalDirectProtoSources,
+          sources,
+          deps,
+          exports,
+          protoSourceRoot,
+          directDescriptorSet,
+          thread.getCallerLocation());
+    }
+  }
 }

src/main/java/com/google/devtools/build/lib/starlarkbuildapi/ProtoInfoApi.java

@@ -16,11 +16,17 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.docgen.annot.DocCategory;
+import com.google.devtools.build.docgen.annot.StarlarkConstructor;
 import com.google.devtools.build.lib.collect.nestedset.Depset;
 import com.google.devtools.build.lib.starlarkbuildapi.core.ProviderApi;
 import com.google.devtools.build.lib.starlarkbuildapi.core.StructApi;
+import net.starlark.java.annot.Param;
+import net.starlark.java.annot.ParamType;
 import net.starlark.java.annot.StarlarkBuiltin;
 import net.starlark.java.annot.StarlarkMethod;
+import net.starlark.java.eval.EvalException;
+import net.starlark.java.eval.Sequence;
+import net.starlark.java.eval.StarlarkThread;
 
 /** Info object propagating information about protocol buffer sources. */
 @StarlarkBuiltin(
@@ -35,11 +41,6 @@
             + "rules_proto</a>."
             + "</p>")
 public interface ProtoInfoApi<FileT extends FileApi> extends StructApi {
-  /** Provider class for {@link ProtoInfoApi} objects. */
-  @StarlarkBuiltin(name = "Provider", documented = false, doc = "")
-  interface ProtoInfoProviderApi extends ProviderApi {
-    // Currently empty. ProtoInfo cannot be created from Starlark at the moment.
-  }
 
   @StarlarkMethod(
       name = "transitive_imports",
@@ -105,4 +106,54 @@ interface ProtoInfoProviderApi extends ProviderApi {
               + " as a source, that source file would be imported as 'import c/d.proto'",
       structField = true)
   String getDirectProtoSourceRoot();
+
+  /** Provider class for {@link ProtoInfoApi} objects. */
+  @StarlarkBuiltin(name = "Provider", documented = false, doc = "")
+  interface ProtoInfoProviderApi extends ProviderApi {
+
+    @StarlarkMethod(
+        name = "ProtoInfo",
+        doc = "The <code>ProtoInfo</code> constructor.",
+        parameters = {
+            @Param(
+                name = "proto_source_root",
+                allowedTypes = {@ParamType(type = String.class)},
+                named = true,
+                doc = "The directory relative to which the .proto files are defined."),
+            @Param(
+                name = "descriptor_set",
+                allowedTypes = { @ParamType(type = FileApi.class)},
+                named = true,
+                doc = "The FileDescriptorSet of the direct sources."),
+            @Param(
+                name = "sources",
+                allowedTypes = {@ParamType(type = Sequence.class, generic1 = FileApi.class)},
+                named = true,
+                defaultValue = "[]",
+                doc = "Proto sources."),
+            @Param(
+                name = "deps",
+                allowedTypes = {@ParamType(type = Sequence.class, generic1 = ProtoInfoApi.class)},
+                named = true,
+                defaultValue = "[]",
+                doc = "Proto dependencies."),
+            @Param(
+                name = "exports",
+                allowedTypes = {@ParamType(type = Sequence.class, generic1 = ProtoInfoApi.class)},
+                named = true,
+                defaultValue = "[]",
+                doc = "Proto exports."),
+        },
+        selfCall = true,
+        useStarlarkThread = true)
+    @StarlarkConstructor
+    ProtoInfoApi<?> protoInfo(
+        String protoSourceRoot,
+        FileApi descriptorSet,
+        Sequence<?> sources,
+        Sequence<?> deps,
+        Sequence<?> exports,
+        StarlarkThread thread)
+        throws EvalException;
+  }
 }

src/test/java/com/google/devtools/build/lib/rules/proto/BUILD

@@ -80,11 +80,14 @@ java_test(
     name = "ProtoInfoStarlarkApiTest",
     srcs = ["ProtoInfoStarlarkApiTest.java"],
     deps = [
+        "//src/main/java/com/google/devtools/build/lib/actions",
         "//src/main/java/com/google/devtools/build/lib/actions:artifacts",
         "//src/main/java/com/google/devtools/build/lib/analysis:configured_target",
         "//src/main/java/com/google/devtools/build/lib/cmdline",
         "//src/main/java/com/google/devtools/build/lib/packages",
+        "//src/main/java/com/google/devtools/build/lib/rules/proto",
         "//src/main/java/com/google/devtools/build/lib/starlarkbuildapi/proto",
+        "//src/main/java/com/google/devtools/build/lib/util",
         "//src/test/java/com/google/devtools/build/lib/actions/util",
         "//src/test/java/com/google/devtools/build/lib/analysis/util",
         "//src/test/java/com/google/devtools/build/lib/packages:testutil",

src/test/java/com/google/devtools/build/lib/rules/proto/ProtoCompileActionBuilderTest.java

@@ -43,6 +43,7 @@
 import com.google.devtools.build.lib.vfs.Root;
 import com.google.devtools.build.lib.vfs.inmemoryfs.InMemoryFileSystem;
 import javax.annotation.Nullable;
+import net.starlark.java.syntax.Location;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.JUnit4;
@@ -90,7 +91,8 @@ private ProtoInfo protoInfo(
         /* strictImportableSources */ NestedSetBuilder.wrap(
             Order.STABLE_ORDER, strictImportableSources),
         /* publicImportSources */ NestedSetBuilder.wrap(
-            Order.STABLE_ORDER, publicImportProtoSources));
+            Order.STABLE_ORDER, publicImportProtoSources),
+        /* location */ Location.fromFileLineColumn("foo", 1, 2));
   }
 
   @Test