hpb: escape NULL enum values and types to NULL_

This change ensures that enums and enum values named NULL are correctly escaped to NULL_ in the generated C++ code,
avoiding conflicts with the NULL macro. Added a regression test case to verify the fix.

PiperOrigin-RevId: 861526129

hpb_generator/gen_enums.cc

@@ -19,6 +19,7 @@
 #include "absl/strings/string_view.h"
 #include "hpb_generator/context.h"
 #include "hpb_generator/gen_utils.h"
+#include "hpb_generator/keywords.h"
 #include "hpb_generator/names.h"
 #include "google/protobuf/descriptor.h"
 
@@ -66,7 +67,7 @@ std::string EnumTypeName(const google::protobuf::EnumDescriptor* enum_descriptor
       return absl::StrCat(kNoPackageNamePrefix,
                           ToCIdent(enum_descriptor->name()));
     }
-    return ToCIdent(enum_descriptor->name());
+    return ResolveKeywordConflict(ToCIdent(enum_descriptor->name()));
   } else {
     // Since the enum is in global name space (no package), it will have the
     // same classified name as the C header include, to prevent collision
@@ -94,7 +95,7 @@ std::string EnumValueSymbolInNameSpace(
     if (desc->file()->package().empty()) {
       return absl::StrCat(kNoPackageNamePrefix, ToCIdent(value->name()));
     }
-    return ToCIdent(value->name());
+    return ResolveKeywordConflict(ToCIdent(value->name()));
   }
 }
 

hpb_generator/gen_extensions.cc

@@ -13,6 +13,7 @@
 #include "absl/strings/str_cat.h"
 #include "hpb_generator/context.h"
 #include "hpb_generator/gen_utils.h"
+#include "hpb_generator/keywords.h"
 #include "hpb_generator/names.h"
 #include "google/protobuf/descriptor.h"
 #include "upb_generator/c/names.h"
@@ -54,7 +55,7 @@ void WriteExtensionIdentifierHeader(const google::protobuf::FieldDescriptor* ext
        {"linkage", linkage},
        {"mini_table_name",
         absl::StrCat(ExtensionIdentifierBase(ext), "_", ext->name(), "_ext")},
-       {"extension_name", ext->name()},
+       {"extension_name", ResolveKeywordConflict(ext->name())},
        {"extension_number", ext->number()}},
       R"cc(
         inline $linkage$ constexpr ::hpb::internal::ExtensionIdentifier<

hpb_generator/gen_messages.cc

@@ -21,6 +21,7 @@
 #include "hpb_generator/gen_enums.h"
 #include "hpb_generator/gen_extensions.h"
 #include "hpb_generator/gen_utils.h"
+#include "hpb_generator/keywords.h"
 #include "hpb_generator/names.h"
 #include "google/protobuf/descriptor.h"
 #include "upb_generator/c/names.h"
@@ -516,21 +517,24 @@ void WriteUsingEnumsInHeader(
             message->full_name()) {
       continue;
     }
-    ctx.Emit({{"enum_name", enum_descriptor->name()}}, "using $enum_name$");
+    ctx.Emit({{"enum_name", ResolveKeywordConflict(enum_descriptor->name())}},
+             "using $enum_name$");
     if (enum_descriptor->options().deprecated()) {
-      ctx.Emit({{"enum_name", enum_descriptor->name()}},
+      ctx.Emit({{"enum_name", ResolveKeywordConflict(enum_descriptor->name())}},
                " ABSL_DEPRECATED(\"Proto enum $enum_name$\")");
     }
     ctx.Emit({{"enum_resolved_type_name", enum_resolved_type_name}},
              " = $enum_resolved_type_name$;\n");
     int value_count = enum_descriptor->value_count();
     for (int i = 0; i < value_count; i++) {
-      ctx.Emit({{"enum_name", enum_descriptor->name()},
-                {"enum_value_name", enum_descriptor->value(i)->name()}},
+      ctx.Emit({{"enum_name", ResolveKeywordConflict(enum_descriptor->name())},
+                {"enum_value_name",
+                 ResolveKeywordConflict(enum_descriptor->value(i)->name())}},
                "static constexpr $enum_name$ $enum_value_name$");
       if (enum_descriptor->options().deprecated() ||
           enum_descriptor->value(i)->options().deprecated()) {
-        ctx.Emit({{"enum_value_name", enum_descriptor->value(i)->name()}},
+        ctx.Emit({{"enum_value_name",
+                   ResolveKeywordConflict(enum_descriptor->value(i)->name())}},
                  " ABSL_DEPRECATED(\"Proto enum value $enum_value_name$\") ");
       }
       ctx.Emit({{"enum_value_symbol",

hpb_generator/tests/BUILD

@@ -52,6 +52,13 @@ proto_library(
     ],
 )
 
+proto_library(
+    name = "null_enum_proto",
+    srcs = [
+        "null_enum.proto",
+    ],
+)
+
 proto_library(
     name = "no_package_enum_user_proto",
     srcs = [
@@ -90,6 +97,12 @@ hpb_proto_library(
     deps = [":naming_conflict_proto"],
 )
 
+hpb_proto_library(
+    name = "null_enum_hpb_proto",
+    visibility = ["//visibility:private"],
+    deps = [":null_enum_proto"],
+)
+
 hpb_proto_library(
     name = "no_package_hpb_proto",
     deps = [
@@ -167,6 +180,7 @@ cc_test(
         ":test_model_hpb_proto",
         ":test_model_upb_proto",
         ":naming_conflict_hpb_proto",
+        ":null_enum_hpb_proto",
         "@googletest//:gtest",
         "@googletest//:gtest_main",
         "@abseil-cpp//absl/status:statusor",

hpb_generator/tests/null_enum.proto

@@ -0,0 +1,22 @@
+syntax = "proto3";
+
+package hpb_test;
+
+enum TestEnumWithNull {
+  TYPE_UNSPECIFIED = 0;
+  NULL = 1;
+}
+
+message MessageWithEnum {
+  enum NestedEnum {
+    NESTED_TYPE_UNSPECIFIED = 0;
+    NULL = 1;
+  }
+}
+
+message MessageWithNullEnum {
+  enum NULL {
+    UNSPECIFIED = 0;
+    VALUE = 1;
+  }
+}

hpb_generator/tests/test_generated.cc

@@ -14,6 +14,7 @@
 #include "absl/strings/string_view.h"
 #include "hpb_generator/tests/child_model.hpb.h"
 #include "hpb_generator/tests/no_package.hpb.h"
+#include "hpb_generator/tests/null_enum.hpb.h"
 #include "hpb_generator/tests/set_alias.hpb.h"
 #include "hpb_generator/tests/test_enum.hpb.h"
 #include "hpb_generator/tests/test_extension.hpb.h"
@@ -50,6 +51,8 @@ TEST(CppGeneratedCode, ImportedEnum) { EXPECT_EQ(3, TestEnum::DEVICE_MONITOR); }
 
 TEST(CppGeneratedCode, Enum) { EXPECT_EQ(1, RED); }
 
+TEST(CppGeneratedCode, NullEnum) { EXPECT_EQ(1, hpb_test::protos::NULL_); }
+
 TEST(CppGeneratedCode, EnumNoPackage) { EXPECT_EQ(1, ::hpb_CELSIUS); }
 
 TEST(CppGeneratedCode, EnumContainingMessage) {