Breaking change: Remove deprecated FieldDescriptor.label

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

PiperOrigin-RevId: 836922631

Author: anandolee

python/descriptor.c

@@ -1054,23 +1054,6 @@ static PyObject* PyUpb_FieldDescriptor_GetCppType(PyUpb_DescriptorBase* self,
   return PyLong_FromLong(cpp_types[upb_FieldDef_CType(self->def)]);
 }
 
-static void WarnDeprecatedLabel(void) {
-  static int deprecated_label_count = 100;
-  if (deprecated_label_count > 0) {
-    --deprecated_label_count;
-    PyErr_WarnEx(
-        PyExc_DeprecationWarning,
-        "label() is deprecated. Use is_required() or is_repeated() instead.",
-        3);
-  }
-}
-
-static PyObject* PyUpb_FieldDescriptor_GetLabel(PyUpb_DescriptorBase* self,
-                                                void* closure) {
-  WarnDeprecatedLabel();
-  return PyLong_FromLong(upb_FieldDef_Label(self->def));
-}
-
 static PyObject* PyUpb_FieldDescriptor_IsRequired(PyUpb_DescriptorBase* self,
                                                   void* closure) {
   return PyBool_FromLong(upb_FieldDef_IsRequired(self->def));
@@ -1186,7 +1169,6 @@ static PyGetSetDef PyUpb_FieldDescriptor_Getters[] = {
     {"file", (getter)PyUpb_FieldDescriptor_GetFile, NULL, "File Descriptor"},
     {"type", (getter)PyUpb_FieldDescriptor_GetType, NULL, "Type"},
     {"cpp_type", (getter)PyUpb_FieldDescriptor_GetCppType, NULL, "C++ Type"},
-    {"label", (getter)PyUpb_FieldDescriptor_GetLabel, NULL, "Label"},
     {"is_required", (getter)PyUpb_FieldDescriptor_IsRequired, NULL,
      "Is Required"},
     {"is_repeated", (getter)PyUpb_FieldDescriptor_IsRepeated, NULL,

python/google/protobuf/descriptor.py

@@ -791,17 +791,6 @@ def type(self):
   def type(self, val):
     self._type = val
 
-  @property
-  def label(self):
-    _Deprecated('label property', 'is_required or is_repeated properties')
-
-    if (
-        self._GetFeatures().field_presence
-        == _FEATURESET_FIELD_PRESENCE_LEGACY_REQUIRED
-    ):
-      return FieldDescriptor.LABEL_REQUIRED
-    return self._label
-
   @property
   def is_required(self):
     """Returns if the field is required."""

python/google/protobuf/internal/field_mask_test.py

@@ -302,7 +302,7 @@ def testMergeMessageWithoutMapFieldsOrFieldPresence(self):
       mask.MergeMessage(src, dst)
       # The expected result message.
       msg = unittest_no_field_presence_pb2.TestAllTypes()
-      if field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
+      if field.is_repeated:
         repeated_src = getattr(src, field_name)
         repeated_msg = getattr(msg, field_name)
         if field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:

python/google/protobuf/internal/message_test.py

@@ -2130,7 +2130,7 @@ def testProto3Optional(self):
       if field.name.startswith('optional_'):
         self.assertTrue(field.has_presence)
     for field in unittest_pb2.TestAllTypes.DESCRIPTOR.fields:
-      if field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
+      if field.is_repeated:
         self.assertFalse(field.has_presence)
       else:
         self.assertTrue(field.has_presence)

python/google/protobuf/pyext/descriptor.cc

@@ -863,22 +863,6 @@ static PyObject* GetCppType(PyBaseDescriptor* self, void* closure) {
   return PyLong_FromLong(_GetDescriptor(self)->cpp_type());
 }
 
-static void WarnDeprecatedLabel() {
-  static int deprecated_label_count = 100;
-  if (deprecated_label_count > 0) {
-    --deprecated_label_count;
-    PyErr_WarnEx(
-        PyExc_DeprecationWarning,
-        "label() is deprecated. Use is_required() or is_repeated() instead.",
-        3);
-  }
-}
-
-static PyObject* GetLabel(PyBaseDescriptor* self, void* closure) {
-  WarnDeprecatedLabel();
-  return PyLong_FromLong(_GetDescriptor(self)->label());
-}
-
 static PyObject* IsRequired(PyBaseDescriptor* self, void* closure) {
   return PyBool_FromLong(_GetDescriptor(self)->is_required());
 }
@@ -1094,7 +1078,6 @@ static PyGetSetDef Getters[] = {
     {"file", (getter)GetFile, nullptr, "File Descriptor"},
     {"type", (getter)GetType, nullptr, "C++ Type"},
     {"cpp_type", (getter)GetCppType, nullptr, "C++ Type"},
-    {"label", (getter)GetLabel, nullptr, "Label"},
     {"is_required", (getter)IsRequired, nullptr, "Is Required"},
     {"is_repeated", (getter)IsRepeated, nullptr, "Is Repeated"},
     {"number", (getter)GetNumber, nullptr, "Number"},