Automated rollback of commit 57702831f9.

PiperOrigin-RevId: 544176749

src/google/protobuf/compiler/cpp/extension.cc

@@ -149,8 +149,27 @@ void ExtensionGenerator::GenerateDeclaration(io::Printer* printer) const {
 }
 
 void ExtensionGenerator::GenerateDefinition(io::Printer* printer) {
-  auto with_vars = printer->WithVars(&variables_);
-  Formatter format(printer);
+  Formatter format(printer, variables_);
+  std::string default_str;
+  // If this is a class member, it needs to be declared in its class scope.
+  if (descriptor_->cpp_type() == FieldDescriptor::CPPTYPE_STRING) {
+    // We need to declare a global string which will contain the default value.
+    // We cannot declare it at class scope because that would require exposing
+    // it in the header which would be annoying for other reasons.  So we
+    // replace :: with _ in the name and declare it as a global.
+    default_str =
+        absl::StrReplaceAll(variables_["scoped_name"], {{"::", "_"}}) +
+        "_default";
+    format("const std::string $1$($2$);\n", default_str,
+           DefaultValue(options_, descriptor_));
+  } else if (descriptor_->message_type()) {
+    // We have to initialize the default instance for extensions at registration
+    // time.
+    default_str = absl::StrCat(FieldMessageTypeName(descriptor_, options_),
+                               "::default_instance()");
+  } else {
+    default_str = DefaultValue(options_, descriptor_);
+  }
 
   // Likewise, class members need to declare the field constant variable.
   if (IsScoped()) {
@@ -166,31 +185,7 @@ void ExtensionGenerator::GenerateDefinition(io::Printer* printer) {
         "::$proto_ns$::internal::ExtensionIdentifier< $extendee$,\n"
         "    ::$proto_ns$::internal::$type_traits$, $field_type$, $packed$>\n"
         "  $scoped_name$($constant_name$);\n");
-  } else if (descriptor_->cpp_type() == descriptor_->CPPTYPE_MESSAGE) {
-    printer->Emit(
-        R"cc(
-          PROTOBUF_ATTRIBUTE_INIT_PRIORITY2
-          ::$proto_ns$::internal::ExtensionIdentifier<
-              $extendee$, ::$proto_ns$::internal::$type_traits$, $field_type$,
-              $packed$>
-              $scoped_name$($constant_name$, $verify_fn$);
-        )cc");
   } else {
-    std::string default_str;
-    // If this is a class member, it needs to be declared in its class scope.
-    if (descriptor_->cpp_type() == FieldDescriptor::CPPTYPE_STRING) {
-      // We need to declare a global string which will contain the default
-      // value. We cannot declare it at class scope because that would require
-      // exposing it in the header which would be annoying for other reasons. So
-      // we replace :: with _ in the name and declare it as a global.
-      default_str =
-          absl::StrReplaceAll(variables_["scoped_name"], {{"::", "_"}}) +
-          "_default";
-      format("const std::string $1$($2$);\n", default_str,
-             DefaultValue(options_, descriptor_));
-    } else {
-      default_str = DefaultValue(options_, descriptor_);
-    }
     format(
         "PROTOBUF_ATTRIBUTE_INIT_PRIORITY2 "
         "::$proto_ns$::internal::ExtensionIdentifier< $extendee$,\n"

src/google/protobuf/extension_set.h

@@ -1358,7 +1358,6 @@ class RepeatedEnumTypeTraits {
 template <typename Type>
 class MessageTypeTraits {
  public:
-  using T = Type;
   typedef const Type& ConstType;
   typedef Type* MutableType;
   typedef MessageTypeTraits<Type> Singular;
@@ -1417,7 +1416,6 @@ class RepeatedMessageGenericTypeTraits;
 template <typename Type>
 class RepeatedMessageTypeTraits {
  public:
-  using T = Type;
   typedef const Type& ConstType;
   typedef Type* MutableType;
   typedef RepeatedMessageTypeTraits<Type> Repeated;
@@ -1531,49 +1529,6 @@ class ExtensionIdentifier {
   typename TypeTraits::ConstType default_value_;
 };
 
-template <typename ExtendeeType, typename Traits, FieldType field_type>
-class MessageExtensionIdentifierImpl {
- public:
-  using Type = typename Traits::T;
-  using TypeTraits = Traits;
-  using Extendee = ExtendeeType;
-
-  MessageExtensionIdentifierImpl(int number, LazyEagerVerifyFnType verify_func)
-      : number_(number) {
-    Register(number, verify_func);
-  }
-  inline int number() const { return number_; }
-
-  static void Register(int number, LazyEagerVerifyFnType verify_func) {
-    TypeTraits::template Register<ExtendeeType>(number, field_type, false,
-                                                verify_func);
-  }
-
-  static const Type& default_value() { return Type::default_instance(); }
-  static const Type& default_value_ref() { return Type::default_instance(); }
-
- private:
-  const int number_;
-};
-
-template <typename ExtendeeType, typename Type, FieldType field_type>
-class ExtensionIdentifier<ExtendeeType, MessageTypeTraits<Type>, field_type,
-                          false>
-    : public MessageExtensionIdentifierImpl<
-          ExtendeeType, MessageTypeTraits<Type>, field_type> {
-  using ExtensionIdentifier::MessageExtensionIdentifierImpl::
-      MessageExtensionIdentifierImpl;
-};
-
-template <typename ExtendeeType, typename Type, FieldType field_type>
-class ExtensionIdentifier<ExtendeeType, RepeatedMessageTypeTraits<Type>,
-                          field_type, false>
-    : public MessageExtensionIdentifierImpl<
-          ExtendeeType, RepeatedMessageTypeTraits<Type>, field_type> {
-  using ExtensionIdentifier::MessageExtensionIdentifierImpl::
-      MessageExtensionIdentifierImpl;
-};
-
 // -------------------------------------------------------------------
 // Generated accessors