Correctly support proto3 optional fields in commonjs+dts .d.ts output (…

…#1184)

* Correctly support proto3 optional fields in commonjs+dts .d.ts output

Fixes #1072

* Use has_optional_keyword instead of is_optional

* Improve the readability of the condition guarding hasXxx .d.ts field generation.

javascript/net/grpc/web/generator/grpc_generator.cc

@@ -825,11 +825,12 @@ void PrintProtoDtsMessage(Printer* printer, const Descriptor* desc,
                      "set$js_field_name$(value?: $js_field_type$): "
                      "$class_name$;\n");
     }
-    if (field->type() == FieldDescriptor::TYPE_MESSAGE &&
-        !field->is_repeated() && !field->is_map()) {
+    if (field->has_optional_keyword() ||
+        (field->type() == FieldDescriptor::TYPE_MESSAGE &&
+            !field->is_repeated() && !field->is_map())) {
       printer->Print(vars, "has$js_field_name$(): boolean;\n");
     }
-    if (field->type() == FieldDescriptor::TYPE_MESSAGE ||
+    if (field->type() == FieldDescriptor::TYPE_MESSAGE || field->has_optional_keyword() ||
         field->is_repeated() || field->is_map()) {
       printer->Print(vars, "clear$js_field_name$(): $class_name$;\n");
     }
@@ -852,10 +853,12 @@ void PrintProtoDtsMessage(Printer* printer, const Descriptor* desc,
 
   for (int i = 0; i < desc->oneof_decl_count(); i++) {
     const OneofDescriptor* oneof = desc->oneof_decl(i);
-    vars["js_oneof_name"] = ToUpperCamel(ParseLowerUnderscore(oneof->name()));
-    printer->Print(
-        vars, "get$js_oneof_name$Case(): $class_name$.$js_oneof_name$Case;\n");
-    printer->Print("\n");
+    if (!oneof->is_synthetic()) {
+      vars["js_oneof_name"] = ToUpperCamel(ParseLowerUnderscore(oneof->name()));
+      printer->Print(
+          vars, "get$js_oneof_name$Case(): $class_name$.$js_oneof_name$Case;\n");
+      printer->Print("\n");
+    }
   }
 
   printer->Print(
@@ -885,7 +888,7 @@ void PrintProtoDtsMessage(Printer* printer, const Descriptor* desc,
     }
     vars["js_field_name"] = js_field_name;
     vars["js_field_type"] = AsObjectFieldType(field, file);
-    if (field->type() != FieldDescriptor::TYPE_MESSAGE ||
+    if ((field->type() != FieldDescriptor::TYPE_MESSAGE && !field->has_optional_keyword()) ||
         field->is_repeated()) {
       printer->Print(vars, "$js_field_name$: $js_field_type$,\n");
     } else {