Breaking Change: Python setdefault behavior change for map field.

-setdefault will be similar with dict for ScalarMap. But both key and value must be set.
  -setdefault will be rejected for MessageMap.

PiperOrigin-RevId: 695768629

python/google/protobuf/internal/containers.py

@@ -412,6 +412,13 @@ class ScalarMap(MutableMapping[_K, _V]):
   def __repr__(self) -> str:
     return repr(self._values)
 
+  def setdefault(self, key: _K, value: Optional[_V] = None) -> _V:
+    if value == None:
+      raise ValueError('The value for scalar map setdefault must be set.')
+    if key not in self._values:
+      self.__setitem__(key, value)
+    return self[key]
+
   def MergeFrom(self, other: 'ScalarMap[_K, _V]') -> None:
     self._values.update(other._values)
     self._message_listener.Modified()
@@ -526,6 +533,12 @@ class MessageMap(MutableMapping[_K, _V]):
   def __repr__(self) -> str:
     return repr(self._values)
 
+  def setdefault(self, key: _K, value: Optional[_V] = None) -> _V:
+    raise NotImplementedError(
+        'Set message map value directly is not supported, call'
+        ' my_map[key].foo = 5'
+    )
+
   def MergeFrom(self, other: 'MessageMap[_K, _V]') -> None:
     # pylint: disable=protected-access
     for key in other._values:

python/google/protobuf/internal/message_test.py

@@ -1900,6 +1900,26 @@ class Proto3Test(unittest.TestCase):
 
     self.assertEqual(msg1.map_int32_int32, msg2.map_int32_int32)
 
+  def testScalarMapSetdefault(self):
+    msg = map_unittest_pb2.TestMap()
+    value = msg.map_int32_int32.setdefault(123, 888)
+    self.assertEqual(value, 888)
+    self.assertEqual(msg.map_int32_int32[123], 888)
+    value = msg.map_int32_int32.setdefault(123, 777)
+    self.assertEqual(value, 888)
+
+    with self.assertRaises(ValueError):
+      value = msg.map_int32_int32.setdefault(1001)
+    self.assertNotIn(1001, msg.map_int32_int32)
+    with self.assertRaises(TypeError):
+      value = msg.map_int32_int32.setdefault()
+    with self.assertRaises(TypeError):
+      value = msg.map_int32_int32.setdefault(1, 2, 3)
+    with self.assertRaises(TypeError):
+      value = msg.map_int32_int32.setdefault("1", 2)
+    with self.assertRaises(TypeError):
+      value = msg.map_int32_int32.setdefault(1, "2")
+
   def testMessageMapComparison(self):
     msg1 = map_unittest_pb2.TestMap()
     msg2 = map_unittest_pb2.TestMap()
@@ -1907,6 +1927,14 @@ class Proto3Test(unittest.TestCase):
     self.assertEqual(msg1.map_int32_foreign_message,
                      msg2.map_int32_foreign_message)
 
+  def testMessageMapSetdefault(self):
+    msg = map_unittest_pb2.TestMap()
+    msg.map_int32_foreign_message[123].c = 888
+    with self.assertRaises(NotImplementedError):
+      msg.map_int32_foreign_message.setdefault(
+          1, msg.map_int32_foreign_message[123]
+      )
+
   def testMapGet(self):
     # Need to test that get() properly returns the default, even though the dict
     # has defaultdict-like semantics.

python/google/protobuf/pyext/map_container.cc

@@ -438,6 +438,35 @@ int MapReflectionFriend::ScalarMapSetItem(PyObject* _self, PyObject* key,
   }
 }
 
+static PyObject* ScalarMapSetdefault(PyObject* self, PyObject* args) {
+  PyObject* key = nullptr;
+  PyObject* default_value = Py_None;
+
+  if (!PyArg_UnpackTuple(args, "setdefault", 1, 2, &key, &default_value)) {
+    return nullptr;
+  }
+
+  if (default_value == Py_None) {
+    PyErr_Format(PyExc_ValueError,
+                 "The value for scalar map setdefault must be set.");
+    return nullptr;
+  }
+
+  ScopedPyObjectPtr is_present(MapReflectionFriend::Contains(self, key));
+  if (is_present == nullptr) {
+    return nullptr;
+  }
+  if (PyObject_IsTrue(is_present.get())) {
+    return MapReflectionFriend::ScalarMapGetItem(self, key);
+  }
+
+  if (MapReflectionFriend::ScalarMapSetItem(self, key, default_value) < 0) {
+    return nullptr;
+  }
+  Py_INCREF(default_value);
+  return default_value;
+}
+
 static PyObject* ScalarMapGet(PyObject* self, PyObject* args,
                               PyObject* kwargs) {
   static const char* kwlist[] = {"key", "default", nullptr};
@@ -512,6 +541,8 @@ static PyMethodDef ScalarMapMethods[] = {
      "Tests whether a key is a member of the map."},
     {"clear", (PyCFunction)Clear, METH_NOARGS,
      "Removes all elements from the map."},
+    {"setdefault", (PyCFunction)ScalarMapSetdefault, METH_VARARGS,
+     "If the key does not exist, insert the key, with the specified value"},
     {"get", (PyCFunction)ScalarMapGet, METH_VARARGS | METH_KEYWORDS,
      "Gets the value for the given key if present, or otherwise a default"},
     {"GetEntryClass", (PyCFunction)GetEntryClass, METH_NOARGS,
@@ -685,6 +716,12 @@ PyObject* MapReflectionFriend::MessageMapToStr(PyObject* _self) {
   return PyObject_Repr(dict.get());
 }
 
+static PyObject* MessageMapSetdefault(PyObject* self, PyObject* args) {
+  PyErr_Format(PyExc_NotImplementedError,
+               "Set message map value directly is not supported.");
+  return nullptr;
+}
+
 PyObject* MessageMapGet(PyObject* self, PyObject* args, PyObject* kwargs) {
   static const char* kwlist[] = {"key", "default", nullptr};
   PyObject* key;
@@ -729,6 +766,8 @@ static PyMethodDef MessageMapMethods[] = {
      "Tests whether the map contains this element."},
     {"clear", (PyCFunction)Clear, METH_NOARGS,
      "Removes all elements from the map."},
+    {"setdefault", (PyCFunction)MessageMapSetdefault, METH_VARARGS,
+     "setdefault is disallowed in MessageMap."},
     {"get", (PyCFunction)MessageMapGet, METH_VARARGS | METH_KEYWORDS,
      "Gets the value for the given key if present, or otherwise a default"},
     {"get_or_create", MapReflectionFriend::MessageMapGetItem, METH_O,

python/map.c

@@ -217,6 +217,48 @@ static PyObject* PyUpb_MapContainer_Clear(PyObject* _self, PyObject* key) {
   Py_RETURN_NONE;
 }
 
+static PyObject* PyUpb_ScalarMapContainer_Setdefault(PyObject* _self,
+                                                     PyObject* args) {
+  PyObject* key;
+  PyObject* default_value = Py_None;
+
+  if (!PyArg_UnpackTuple(args, "setdefault", 1, 2, &key, &default_value)) {
+    return NULL;
+  }
+
+  if (default_value == Py_None) {
+    PyErr_Format(PyExc_ValueError,
+                 "The value for scalar map setdefault must be set.");
+    return NULL;
+  }
+
+  PyUpb_MapContainer* self = (PyUpb_MapContainer*)_self;
+  upb_Map* map = PyUpb_MapContainer_EnsureReified(_self);
+  const upb_FieldDef* f = PyUpb_MapContainer_GetField(self);
+  const upb_MessageDef* entry_m = upb_FieldDef_MessageSubDef(f);
+  const upb_FieldDef* key_f = upb_MessageDef_Field(entry_m, 0);
+  const upb_FieldDef* val_f = upb_MessageDef_Field(entry_m, 1);
+  upb_MessageValue u_key, u_val;
+  if (!PyUpb_PyToUpb(key, key_f, &u_key, NULL)) return NULL;
+  if (upb_Map_Get(map, u_key, &u_val)) {
+    return PyUpb_UpbToPy(u_val, val_f, self->arena);
+  }
+
+  upb_Arena* arena = PyUpb_Arena_Get(self->arena);
+  if (!PyUpb_PyToUpb(default_value, val_f, &u_val, arena)) return NULL;
+  if (!PyUpb_MapContainer_Set(self, map, u_key, u_val, arena)) return NULL;
+
+  Py_INCREF(default_value);
+  return default_value;
+}
+
+static PyObject* PyUpb_MessageMapContainer_Setdefault(PyObject* self,
+                                                      PyObject* args) {
+  PyErr_Format(PyExc_NotImplementedError,
+               "Set message map value directly is not supported.");
+  return NULL;
+}
+
 static PyObject* PyUpb_MapContainer_Get(PyObject* _self, PyObject* args,
                                         PyObject* kwargs) {
   PyUpb_MapContainer* self = (PyUpb_MapContainer*)_self;
@@ -331,6 +373,9 @@ PyObject* PyUpb_MapContainer_GetOrCreateWrapper(upb_Map* map,
 static PyMethodDef PyUpb_ScalarMapContainer_Methods[] = {
     {"clear", PyUpb_MapContainer_Clear, METH_NOARGS,
      "Removes all elements from the map."},
+    {"setdefault", (PyCFunction)PyUpb_ScalarMapContainer_Setdefault,
+     METH_VARARGS,
+     "If the key does not exist, insert the key, with the specified value"},
     {"get", (PyCFunction)PyUpb_MapContainer_Get, METH_VARARGS | METH_KEYWORDS,
      "Gets the value for the given key if present, or otherwise a default"},
     {"GetEntryClass", PyUpb_MapContainer_GetEntryClass, METH_NOARGS,
@@ -373,6 +418,8 @@ static PyType_Spec PyUpb_ScalarMapContainer_Spec = {
 static PyMethodDef PyUpb_MessageMapContainer_Methods[] = {
     {"clear", PyUpb_MapContainer_Clear, METH_NOARGS,
      "Removes all elements from the map."},
+    {"setdefault", (PyCFunction)PyUpb_MessageMapContainer_Setdefault,
+     METH_VARARGS, "setdefault is disallowed in MessageMap."},
     {"get", (PyCFunction)PyUpb_MapContainer_Get, METH_VARARGS | METH_KEYWORDS,
      "Gets the value for the given key if present, or otherwise a default"},
     {"get_or_create", PyUpb_MapContainer_Subscript, METH_O,
@@ -481,7 +528,7 @@ bool PyUpb_Map_Init(PyObject* m) {
   if (!base) return false;
 
   const char* methods[] = {"keys", "items",   "values", "__eq__", "__ne__",
-                           "pop",  "popitem", "update", "setdefault", NULL};
+                           "pop",  "popitem", "update", NULL};
 
   state->message_map_container_type = PyUpb_AddClassWithRegister(
       m, &PyUpb_MessageMapContainer_Spec, base, methods);