feat: Add support for rest numeric enums.

rules_java_gapic/java_gapic.bzl

@@ -189,6 +189,7 @@ def _java_gapic_srcjar(
         service_yaml,
         # possible values are: "grpc", "rest", "grpc+rest"
         transport,
+        rest_numeric_enums,
         # Can be used to provide a java_library with a customized generator,
         # like the one which dumps descriptor to a file for future debugging.
         java_generator_name = "java_gapic",
@@ -213,6 +214,9 @@ def _java_gapic_srcjar(
     if transport:
         opt_args.append("transport=%s" % transport)
 
+    if rest_numeric_enums:
+        opt_args.append("rest-numeric-enums")
+
     # Produces the GAPIC metadata file if this flag is set. to any value.
     # Protoc invocation: --java_gapic_opt=metadata
     plugin_args = ["metadata"]
@@ -240,6 +244,7 @@ def java_gapic_library(
         test_deps = [],
         # possible values are: "grpc", "rest", "grpc+rest"
         transport = None,
+        rest_numeric_enums = False,
         **kwargs):
     srcjar_name = name + "_srcjar"
     raw_srcjar_name = srcjar_name + "_raw"
@@ -251,6 +256,7 @@ def java_gapic_library(
         gapic_yaml = gapic_yaml,
         service_yaml = service_yaml,
         transport = transport,
+        rest_numeric_enums = rest_numeric_enums,
         java_generator_name = "java_gapic",
         **kwargs
     )
@@ -391,6 +397,7 @@ def java_generator_request_dump(
         gapic_yaml = None,
         service_yaml = None,
         transport = None,
+        rest_numeric_enums = False,
         **kwargs):
     _java_gapic_srcjar(
         name = name,
@@ -399,6 +406,7 @@ def java_generator_request_dump(
         gapic_yaml = gapic_yaml,
         service_yaml = service_yaml,
         transport = transport,
+        rest_numeric_enums = rest_numeric_enums,
         java_generator_name = "code_generator_request_dumper",
         **kwargs
     )

src/main/java/com/google/api/generator/gapic/composer/common/AbstractTransportServiceStubClassComposer.java

@@ -187,7 +187,8 @@ public GapicClass generate(GapicContext context, Service service) {
             protoMethodNameToDescriptorVarExprs,
             callableClassMemberVarExprs,
             classMemberVarExprs,
-            messageTypes);
+            messageTypes,
+            context.restNumericEnumsEnabled());
 
     StubCommentComposer commentComposer =
         new StubCommentComposer(getTransportContext().transportNames().get(0));
@@ -225,7 +226,8 @@ protected abstract Statement createMethodDescriptorVariableDecl(
       Service service,
       Method protoMethod,
       VariableExpr methodDescriptorVarExpr,
-      Map<String, Message> messageTypes);
+      Map<String, Message> messageTypes,
+      boolean restNumericEnumsEnabled);
 
   protected boolean generateOperationsStubLogic(Service service) {
     return true;
@@ -274,7 +276,8 @@ protected List<Statement> createClassStatements(
       Map<String, VariableExpr> protoMethodNameToDescriptorVarExprs,
       Map<String, VariableExpr> callableClassMemberVarExprs,
       Map<String, VariableExpr> classMemberVarExprs,
-      Map<String, Message> messageTypes) {
+      Map<String, Message> messageTypes,
+      boolean restNumericEnumsEnabled) {
     List<Statement> classStatements = new ArrayList<>();
 
     classStatements.addAll(createTypeRegistry(service));
@@ -284,7 +287,7 @@ protected List<Statement> createClassStatements(
 
     for (Statement statement :
         createMethodDescriptorVariableDecls(
-            service, protoMethodNameToDescriptorVarExprs, messageTypes)) {
+            service, protoMethodNameToDescriptorVarExprs, messageTypes, restNumericEnumsEnabled)) {
       classStatements.add(statement);
       classStatements.add(EMPTY_LINE_STATEMENT);
     }
@@ -301,13 +304,18 @@ protected List<Statement> createClassStatements(
   protected List<Statement> createMethodDescriptorVariableDecls(
       Service service,
       Map<String, VariableExpr> protoMethodNameToDescriptorVarExprs,
-      Map<String, Message> messageTypes) {
+      Map<String, Message> messageTypes,
+      boolean restNumericEnumsEnabled) {
     return service.methods().stream()
         .filter(this::isSupportedMethod)
         .map(
             m ->
                 createMethodDescriptorVariableDecl(
-                    service, m, protoMethodNameToDescriptorVarExprs.get(m.name()), messageTypes))
+                    service,
+                    m,
+                    protoMethodNameToDescriptorVarExprs.get(m.name()),
+                    messageTypes,
+                    restNumericEnumsEnabled))
         .collect(Collectors.toList());
   }
 

src/main/java/com/google/api/generator/gapic/composer/grpc/GrpcServiceStubClassComposer.java

@@ -95,7 +95,8 @@ protected Statement createMethodDescriptorVariableDecl(
       Service service,
       Method protoMethod,
       VariableExpr methodDescriptorVarExpr,
-      Map<String, Message> messageTypes) {
+      Map<String, Message> messageTypes,
+      boolean restNumericEnumsEnabled) {
     MethodInvocationExpr methodDescriptorMaker =
         MethodInvocationExpr.builder()
             .setMethodName("newBuilder")

src/main/java/com/google/api/generator/gapic/composer/rest/HttpJsonServiceStubClassComposer.java

@@ -129,7 +129,8 @@ protected Statement createMethodDescriptorVariableDecl(
       Service service,
       Method protoMethod,
       VariableExpr methodDescriptorVarExpr,
-      Map<String, Message> messageTypes) {
+      Map<String, Message> messageTypes,
+      boolean restNumericEnumsEnabled) {
     MethodInvocationExpr expr =
         MethodInvocationExpr.builder()
             .setMethodName("newBuilder")
@@ -152,7 +153,11 @@ protected Statement createMethodDescriptorVariableDecl(
     expr = methodMaker.apply("setHttpMethod", getHttpMethodTypeExpr(protoMethod)).apply(expr);
     expr = methodMaker.apply("setType", getMethodTypeExpr(protoMethod)).apply(expr);
     expr =
-        methodMaker.apply("setRequestFormatter", getRequestFormatterExpr(protoMethod)).apply(expr);
+        methodMaker
+            .apply(
+                "setRequestFormatter",
+                getRequestFormatterExpr(protoMethod, restNumericEnumsEnabled))
+            .apply(expr);
     expr = methodMaker.apply("setResponseParser", setResponseParserExpr(protoMethod)).apply(expr);
 
     if (protoMethod.isOperationPollingMethod() || protoMethod.hasLro()) {
@@ -320,7 +325,7 @@ protected List<MethodDefinition> createGetMethodDescriptorsMethod(
                 .build();
   }
 
-  private List<Expr> getRequestFormatterExpr(Method protoMethod) {
+  private List<Expr> getRequestFormatterExpr(Method protoMethod, boolean restNumericEnumsEnabled) {
     BiFunction<String, List<Expr>, Function<MethodInvocationExpr, MethodInvocationExpr>>
         methodMaker = getMethodMaker();
 
@@ -351,7 +356,8 @@ private List<Expr> getRequestFormatterExpr(Method protoMethod) {
                         protoMethod,
                         extractorVarType,
                         protoMethod.httpBindings().pathParameters(),
-                        "putPathParam")))
+                        "putPathParam",
+                        restNumericEnumsEnabled)))
             .apply(expr);
 
     if (!protoMethod.httpBindings().lowerCamelAdditionalPatterns().isEmpty()) {
@@ -387,7 +393,8 @@ private List<Expr> getRequestFormatterExpr(Method protoMethod) {
                         protoMethod,
                         extractorVarType,
                         protoMethod.httpBindings().queryParameters(),
-                        "putQueryParam")))
+                        "putQueryParam",
+                        restNumericEnumsEnabled)))
             .apply(expr);
 
     extractorVarType = TypeNode.STRING;
@@ -404,7 +411,8 @@ private List<Expr> getRequestFormatterExpr(Method protoMethod) {
                             ? protoMethod.httpBindings().pathParameters()
                             : protoMethod.httpBindings().bodyParameters(),
                         "toBody",
-                        asteriskBody)))
+                        asteriskBody,
+                        restNumericEnumsEnabled)))
             .apply(expr);
     expr = methodMaker.apply("build", Collections.emptyList()).apply(expr);
 
@@ -771,7 +779,8 @@ private Expr createBodyFieldsExtractorClassInstance(
       TypeNode extractorReturnType,
       Set<HttpBinding> httpBindingFieldNames,
       String serializerMethodName,
-      boolean asteriskBody) {
+      boolean asteriskBody,
+      boolean restNumericEnumEnabled) {
     List<Statement> bodyStatements = new ArrayList<>();
 
     Expr returnExpr = null;
@@ -787,7 +796,6 @@ private Expr createBodyFieldsExtractorClassInstance(
             Variable.builder().setType(method.inputType()).setName("request").build());
     Expr bodyRequestExpr = requestVarExpr;
     String requestMethodPrefix = "get";
-    String bodyParamName = null;
 
     if (asteriskBody) {
       bodyRequestExpr =
@@ -805,7 +813,6 @@ private Expr createBodyFieldsExtractorClassInstance(
       // Handle foo.bar cases by descending into the subfields.
       MethodInvocationExpr.Builder requestFieldMethodExprBuilder =
           MethodInvocationExpr.builder().setExprReferenceExpr(prevExpr);
-      bodyParamName = JavaStyle.toLowerCamelCase(httpBindingFieldName.name());
       String[] descendantFields = httpBindingFieldName.name().split("\\.");
       if (asteriskBody && descendantFields.length > 1) {
         // This is the `body: "*"` case, do not clean nested body fields as it a very rare, not
@@ -839,11 +846,16 @@ private Expr createBodyFieldsExtractorClassInstance(
                 .setExprReferenceExpr(prevExpr)
                 .setMethodName("build")
                 .build();
-        bodyParamName = "*";
       }
-      paramsPutArgs.add(ValueExpr.withValue(StringObjectValue.withValue(bodyParamName)));
       paramsPutArgs.add(prevExpr);
 
+      PrimitiveValue primitiveValue =
+          PrimitiveValue.builder()
+              .setType(TypeNode.BOOLEAN)
+              .setValue(String.valueOf(restNumericEnumEnabled))
+              .build();
+      paramsPutArgs.add(ValueExpr.withValue(primitiveValue));
+
       returnExpr =
           MethodInvocationExpr.builder()
               .setExprReferenceExpr(serializerExpr)
@@ -866,7 +878,8 @@ private Expr createFieldsExtractorClassInstance(
       Method method,
       TypeNode extractorReturnType,
       Set<HttpBinding> httpBindingFieldNames,
-      String serializerMethodName) {
+      String serializerMethodName,
+      boolean restNumericEnumsEnabled) {
     List<Statement> bodyStatements = new ArrayList<>();
 
     VariableExpr fieldsVarExpr =
@@ -980,6 +993,23 @@ private Expr createFieldsExtractorClassInstance(
       }
     }
 
+    if (restNumericEnumsEnabled && serializerMethodName.equals("putQueryParam")) {
+      ImmutableList.Builder<Expr> paramsPutArgs = ImmutableList.builder();
+
+      paramsPutArgs.add(fieldsVarExpr);
+      paramsPutArgs.add(ValueExpr.withValue(StringObjectValue.withValue("$alt")));
+      paramsPutArgs.add(ValueExpr.withValue(StringObjectValue.withValue("json;enum-encoding=int")));
+
+      Expr paramsPutExpr =
+          MethodInvocationExpr.builder()
+              .setExprReferenceExpr(serializerVarExpr)
+              .setMethodName(serializerMethodName)
+              .setArguments(paramsPutArgs.build())
+              .setReturnType(extractorReturnType)
+              .build();
+      bodyStatements.add(ExprStatement.withExpr(paramsPutExpr));
+    }
+
     // Overrides FieldsExtractor
     // (https://github.com/googleapis/gax-java/blob/12b18ee255d3fabe13bb3969df40753b29f830d5/gax-httpjson/src/main/java/com/google/api/gax/httpjson/FieldsExtractor.java).
     return LambdaExpr.builder()

src/main/java/com/google/api/generator/gapic/model/GapicContext.java

@@ -47,6 +47,8 @@ public abstract class GapicContext {
 
   public abstract boolean gapicMetadataEnabled();
 
+  public abstract boolean restNumericEnumsEnabled();
+
   public GapicMetadata gapicMetadata() {
     return gapicMetadata;
   }
@@ -81,7 +83,8 @@ static GapicMetadata defaultGapicMetadata() {
   public static Builder builder() {
     return new AutoValue_GapicContext.Builder()
         .setMixinServices(Collections.emptyList())
-        .setGapicMetadataEnabled(false);
+        .setGapicMetadataEnabled(false)
+        .setRestNumericEnumsEnabled(false);
   }
 
   @AutoValue.Builder
@@ -108,6 +111,8 @@ public Builder setHelperResourceNames(Set<ResourceName> helperResourceNames) {
 
     public abstract Builder setGapicMetadataEnabled(boolean gapicMetadataEnabled);
 
+    public abstract Builder setRestNumericEnumsEnabled(boolean restNumericEnumsEnabled);
+
     public abstract Builder setTransport(Transport transport);
 
     abstract ImmutableMap<String, ResourceName> resourceNames();

src/main/java/com/google/api/generator/gapic/protoparser/Parser.java

@@ -120,6 +120,7 @@ public static GapicContext parse(CodeGeneratorRequest request) {
     Optional<String> transportOpt = PluginArgumentParser.parseTransport(request);
 
     boolean willGenerateMetadata = PluginArgumentParser.hasMetadataFlag(request);
+    boolean willGenerateNumericEnum = PluginArgumentParser.hasNumericEnumFlag(request);
 
     Optional<String> serviceConfigPathOpt = PluginArgumentParser.parseJsonConfigPath(request);
     Optional<GapicServiceConfig> serviceConfigOpt =
@@ -216,6 +217,7 @@ public static GapicContext parse(CodeGeneratorRequest request) {
         .setGapicMetadataEnabled(willGenerateMetadata)
         .setServiceYamlProto(serviceYamlProtoOpt.orElse(null))
         .setTransport(transport)
+        .setRestNumericEnumsEnabled(willGenerateNumericEnum)
         .build();
   }
 

src/main/java/com/google/api/generator/gapic/protoparser/PluginArgumentParser.java

@@ -29,6 +29,7 @@ public class PluginArgumentParser {
   @VisibleForTesting static final String KEY_GRPC_SERVICE_CONFIG = "grpc-service-config";
   @VisibleForTesting static final String KEY_GAPIC_CONFIG = "gapic-config";
   @VisibleForTesting static final String KEY_METADATA = "metadata";
+  @VisibleForTesting static final String KEY_NUMERIC_ENUM = "rest-numeric-enums";
   @VisibleForTesting static final String KEY_SERVICE_YAML_CONFIG = "api-service-config";
   @VisibleForTesting static final String KEY_TRANSPORT = "transport";
 
@@ -53,7 +54,11 @@ static Optional<String> parseTransport(CodeGeneratorRequest request) {
   }
 
   static boolean hasMetadataFlag(CodeGeneratorRequest request) {
-    return hasMetadataFlag(request.getParameter());
+    return hasFlag(request.getParameter(), KEY_METADATA);
+  }
+
+  static boolean hasNumericEnumFlag(CodeGeneratorRequest request) {
+    return hasFlag(request.getParameter(), KEY_NUMERIC_ENUM);
   }
 
   /** Expects a comma-separated list of file paths. */
@@ -89,8 +94,8 @@ private static Optional<String> parseConfigArgument(String pluginProtocArgument,
   }
 
   @VisibleForTesting
-  static boolean hasMetadataFlag(String pluginProtocArgument) {
-    return Arrays.stream(pluginProtocArgument.split(COMMA)).anyMatch(s -> s.equals(KEY_METADATA));
+  static boolean hasFlag(String pluginProtocArgument, String flagKey) {
+    return Arrays.asList(pluginProtocArgument.split(COMMA)).contains(flagKey);
   }
 
   private static Optional<String> parseFileArgument(