From d3daee4c68c7e067c4a9f4ae620a7fa41a4c6428 Mon Sep 17 00:00:00 2001
From: Samuel Benzaquen <sbenza@google.com>
Date: Tue, 25 Aug 2026 07:22:35 -0700
Subject: [PATCH] Continue cleaning up after the GLOBALS experiment.

Remove branching for MessageGlobalsBase and the trait.

PiperOrigin-RevId: 970537151
---
 src/google/protobuf/message_lite.h       | 43 +-----------------------
 src/google/protobuf/message_traits.h     | 10 +++---
 src/google/protobuf/message_unittest.inc |  3 --
 src/google/protobuf/repeated_ptr_field.h |  4 +--
 4 files changed, 8 insertions(+), 52 deletions(-)

diff --git a/src/google/protobuf/message_lite.h b/src/google/protobuf/message_lite.h
index 27eed7351b..151d055ce7 100644
--- a/src/google/protobuf/message_lite.h
+++ b/src/google/protobuf/message_lite.h
@@ -247,31 +247,7 @@ PROTOBUF_EXPORT inline const std::string& GetEmptyStringAlreadyInited() {
   return fixed_address_empty_string.get();
 }
 
-#ifndef PROTOBUF_MESSAGE_GLOBALS
-struct MessageGlobalsBase {
-  template <typename T = MessageLite>
-  static const T* ToDefaultInstance(const void* globals) {
-    return reinterpret_cast<const T*>(globals);
-  }
-
-  static const MessageGlobalsBase* FromDefaultInstance(
-      const void* default_instance) {
-    return reinterpret_cast<const MessageGlobalsBase*>(default_instance);
-  }
-
-  static const MessageGlobalsBase* FromClassData(const ClassData* class_data) {
-    return FromDefaultInstance(class_data->default_instance());
-  }
-};
-
-template <const auto* kDefault, const auto* kClassData>
-struct GeneratedMessageTraitsT {
-  static constexpr const void* default_instance() { return kDefault; }
-  static constexpr const auto* class_data() { return kClassData->base(); }
-  static constexpr const auto* tc_table() { return class_data()->tc_table; }
-  static constexpr auto StrongPointer() { return default_instance(); }
-};
-#else
+// TODO: Remove unnecessary members, or move into ClassData.
 struct MessageGlobalsBase {
   template <size_t R, size_t KnownAlignment = 0>
   static constexpr size_t RoundUpTo(size_t n) {
@@ -327,16 +303,9 @@ struct MessageGlobalsBase {
 
 template <const auto* kGlobals>
 struct GeneratedMessageTraitsT {
-  static const void* default_instance() {
-    return MessageGlobalsBase::ToDefaultInstance(kGlobals);
-  }
   static const auto* class_data() {
     return MessageGlobalsBase::GetClassData(kGlobals);
   }
-  static const auto* tc_table() {
-    return MessageGlobalsBase::ToParseTableBase(kGlobals);
-  }
-  static constexpr const auto* globals() { return kGlobals; }
   static constexpr auto StrongPointer() { return kGlobals; }
 };
 
@@ -345,22 +314,12 @@ inline const MessageLite* ClassData::default_instance() const {
   return MessageGlobalsBase::ToDefaultInstance(this);
 }
 
-#endif  // PROTOBUF_MESSAGE_GLOBALS
-
 inline const TcParseTableBase* ClassData::GetTcParseTable() const {
-#ifdef PROTOBUF_MESSAGE_GLOBALS
   if (ABSL_PREDICT_FALSE(is_dynamic)) {
-#else
-  if (ABSL_PREDICT_FALSE(tc_table == nullptr)) {
-#endif
     ABSL_DCHECK(!is_lite);
     return descriptor_methods()->get_tc_table(this);
   }
-#ifdef PROTOBUF_MESSAGE_GLOBALS
   return MessageGlobalsBase::ToParseTableBase(this);
-#else
-  return tc_table;
-#endif
 }
 
 }  // namespace internal
diff --git a/src/google/protobuf/message_traits.h b/src/google/protobuf/message_traits.h
index 7bdcbf1e45..85742c847e 100644
--- a/src/google/protobuf/message_traits.h
+++ b/src/google/protobuf/message_traits.h
@@ -24,18 +24,18 @@ class MessageLite;
 
 namespace internal {
 
+struct MessageGlobalsBase;
 struct ClassData;
 
 template <typename MessageT>
 const ClassData* GetClassData(const MessageT& msg);
 
-template <typename T>
+template <typename T, typename Globals = MessageGlobalsBase>
 struct FallbackMessageTraits {
-  static const void* default_instance() { return &T::default_instance(); }
-  static constexpr const auto* class_data() {
-    return GetClassData(static_cast<const MessageLite&>(T::default_instance()));
+  static const auto* class_data() {
+    return Globals::GetClassData(
+        Globals::FromDefaultInstance(&T::default_instance()));
   }
-  static const auto* tc_table() { return class_data()->GetTcParseTable(); }
   // We can't make a constexpr pointer to the default, so use a function pointer
   // instead.
   static constexpr auto StrongPointer() { return &T::default_instance; }
diff --git a/src/google/protobuf/message_unittest.inc b/src/google/protobuf/message_unittest.inc
index 74d949421a..74baa2ac4e 100644
--- a/src/google/protobuf/message_unittest.inc
+++ b/src/google/protobuf/message_unittest.inc
@@ -1672,9 +1672,6 @@ TEST(MESSAGE_TEST_NAME, MOMIParserEdgeCases) {
 }
 
 TEST(MESSAGE_TEST_NAME, MessageTraitsWork) {
-  EXPECT_EQ(
-      &UNITTEST::TestAllTypes::default_instance(),
-      internal::MessageTraits<UNITTEST::TestAllTypes>::default_instance());
   EXPECT_EQ(internal::GetClassData(UNITTEST::TestAllTypes::default_instance()),
             internal::MessageTraits<UNITTEST::TestAllTypes>::class_data());
 }
diff --git a/src/google/protobuf/repeated_ptr_field.h b/src/google/protobuf/repeated_ptr_field.h
index 345b396c46..643d44390d 100644
--- a/src/google/protobuf/repeated_ptr_field.h
+++ b/src/google/protobuf/repeated_ptr_field.h
@@ -1133,8 +1133,8 @@ class GenericTypeHandler {
 
   static const Type& default_instance() {
     static_assert(has_default_instance());
-    return *static_cast<const GenericType*>(
-        MessageTraits<Type>::default_instance());
+    return *reinterpret_cast<const GenericType*>(
+        MessageTraits<Type>::class_data()->default_instance());
   }
   static constexpr bool has_default_instance() {
     return !std::is_same_v<Type, Message> && !std::is_same_v<Type, MessageLite>;