Breaking Change: Remove deprecated FieldDescriptor::label() in OSS. Use is_repeated() or is_required() instead

https://protobuf.dev/news/2025-09-19/#cpp-remove-apis

PiperOrigin-RevId: 845462045

Author: anandolee

editions/generated_files_test.cc

@@ -57,7 +57,6 @@ TEST(Generated, RequiredPresence) {
   ASSERT_THAT(field, NotNull());
   EXPECT_TRUE(field->has_presence());
   EXPECT_TRUE(field->is_required());
-  EXPECT_EQ(field->label(), FieldDescriptor::LABEL_REQUIRED);
 }
 
 TEST(Generated, ImplicitPresence) {

python/google/protobuf/pyext/extension_dict.cc

@@ -197,7 +197,7 @@ int ass_subscript(ExtensionDict* self, PyObject* key, PyObject* value) {
     return cmessage::ClearFieldByDescriptor(self->parent, descriptor);
   }
 
-  if (descriptor->label() != FieldDescriptor::LABEL_OPTIONAL ||
+  if (descriptor->is_repeated() || descriptor->is_required() ||
       descriptor->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
     PyErr_SetString(PyExc_TypeError,
                     "Extension is repeated and/or composite "
@@ -218,7 +218,7 @@ static const FieldDescriptor* FindMessageSetExtension(
     if (extension->is_extension() &&
         extension->containing_type()->options().message_set_wire_format() &&
         extension->type() == FieldDescriptor::TYPE_MESSAGE &&
-        extension->label() == FieldDescriptor::LABEL_OPTIONAL &&
+        (!extension->is_repeated() && !extension->is_required()) &&
         extension->message_type() == message_descriptor) {
       return extension;
     }

src/google/protobuf/descriptor.h

@@ -931,11 +931,6 @@ class PROTOBUF_EXPORT FieldDescriptor : private internal::SymbolBase,
   // Name of the C++ type.
   absl::string_view cpp_type_name() const;
 
-  // This should never be called directly. Use is_required() and is_repeated()
-  // helper methods instead.
-  ABSL_DEPRECATED("Use is_required() or is_repeated() instead.")
-  Label label() const;  // optional/required/repeated
-
 #ifndef SWIG
   CppStringType cpp_string_type() const;  // The C++ string type of this field.
 #endif
@@ -2925,16 +2920,6 @@ inline const Descriptor* FieldDescriptor::extension_scope() const {
   return scope_.extension_scope;
 }
 
-inline FieldDescriptor::Label FieldDescriptor::label() const {
-  if (is_required()) {
-    return LABEL_REQUIRED;
-  } else if (is_repeated()) {
-    return LABEL_REPEATED;
-  } else {
-    return LABEL_OPTIONAL;
-  }
-}
-
 inline FieldDescriptor::Type FieldDescriptor::type() const {
   return static_cast<Type>(type_);
 }

src/google/protobuf/descriptor_unittest.cc

@@ -1218,11 +1218,6 @@ TEST_F(DescriptorTest, FieldType) {
 }
 
 TEST_F(DescriptorTest, FieldLabel) {
-  EXPECT_EQ(FieldDescriptor::LABEL_REQUIRED, foo_->label());
-  EXPECT_EQ(FieldDescriptor::LABEL_OPTIONAL, bar_->label());
-  EXPECT_EQ(FieldDescriptor::LABEL_REPEATED, baz_->label());
-  EXPECT_EQ(FieldDescriptor::LABEL_OPTIONAL, moo_->label());
-
   EXPECT_TRUE(foo_->is_required());
   EXPECT_FALSE((!foo_->is_repeated() && !foo_->is_required()));
   EXPECT_FALSE(foo_->is_repeated());
@@ -2548,10 +2543,12 @@ TEST_F(ExtensionDescriptorTest, Extensions) {
   EXPECT_EQ(moo_, bar_->extension(0)->message_type());
   EXPECT_EQ(moo_, bar_->extension(1)->message_type());
 
-  EXPECT_EQ(FieldDescriptor::LABEL_OPTIONAL, foo_file_->extension(0)->label());
-  EXPECT_EQ(FieldDescriptor::LABEL_REPEATED, foo_file_->extension(1)->label());
-  EXPECT_EQ(FieldDescriptor::LABEL_OPTIONAL, bar_->extension(0)->label());
-  EXPECT_EQ(FieldDescriptor::LABEL_REPEATED, bar_->extension(1)->label());
+  EXPECT_FALSE(foo_file_->extension(0)->is_required());
+  EXPECT_FALSE(foo_file_->extension(0)->is_repeated());
+  EXPECT_TRUE(foo_file_->extension(1)->is_repeated());
+  EXPECT_FALSE(bar_->extension(0)->is_required());
+  EXPECT_FALSE(bar_->extension(0)->is_repeated());
+  EXPECT_TRUE(bar_->extension(1)->is_repeated());
 
   EXPECT_EQ(foo_, foo_file_->extension(0)->containing_type());
   EXPECT_EQ(foo_, foo_file_->extension(1)->containing_type());
@@ -9637,7 +9634,6 @@ TEST_F(FeaturesTest, RestoresLabelRoundTrip) {
     }
   )pb");
   const FieldDescriptor* field = file->message_type(0)->field(0);
-  ASSERT_EQ(field->label(), FieldDescriptor::LABEL_REQUIRED);
   ASSERT_TRUE(field->is_required());
 
   FileDescriptorProto proto;