[5.1.x] Fixed #35561 -- Made *args and **kwargs parsing more strict in Model.save()/asave().

Backport of e56a32b89b from main.

django/db/models/base.py

@@ -776,6 +776,43 @@ class Model(AltersData, metaclass=ModelBase):
             return getattr(self, field_name)
         return getattr(self, field.attname)
 
+    # RemovedInDjango60Warning: When the deprecation ends, remove completely.
+    def _parse_params(self, *args, method_name, **kwargs):
+        defaults = {
+            "force_insert": False,
+            "force_update": False,
+            "using": None,
+            "update_fields": None,
+        }
+
+        warnings.warn(
+            f"Passing positional arguments to {method_name}() is deprecated",
+            RemovedInDjango60Warning,
+            stacklevel=2,
+        )
+        total_len_args = len(args) + 1  # include self
+        max_len_args = len(defaults) + 1
+        if total_len_args > max_len_args:
+            # Recreate the proper TypeError message from Python.
+            raise TypeError(
+                f"Model.{method_name}() takes from 1 to {max_len_args} positional "
+                f"arguments but {total_len_args} were given"
+            )
+
+        def get_param(param_name, param_value, arg_index):
+            if arg_index < len(args):
+                if param_value is not defaults[param_name]:
+                    # Recreate the proper TypeError message from Python.
+                    raise TypeError(
+                        f"Model.{method_name}() got multiple values for argument "
+                        f"'{param_name}'"
+                    )
+                return args[arg_index]
+
+            return param_value
+
+        return [get_param(k, v, i) for i, (k, v) in enumerate(kwargs.items())]
+
     # RemovedInDjango60Warning: When the deprecation ends, replace with:
     # def save(
     #   self, *, force_insert=False, force_update=False, using=None, update_fields=None,
@@ -798,25 +835,14 @@ class Model(AltersData, metaclass=ModelBase):
         """
         # RemovedInDjango60Warning.
         if args:
-            warnings.warn(
-                "Passing positional arguments to save() is deprecated",
-                RemovedInDjango60Warning,
-                stacklevel=2,
+            force_insert, force_update, using, update_fields = self._parse_params(
+                *args,
+                method_name="save",
+                force_insert=force_insert,
+                force_update=force_update,
+                using=using,
+                update_fields=update_fields,
             )
-            total_len_args = len(args) + 1  # include self
-            if total_len_args > 5:
-                # Recreate the proper TypeError message from Python.
-                raise TypeError(
-                    "Model.save() takes from 1 to 5 positional arguments but "
-                    f"{total_len_args} were given"
-                )
-            force_insert = args[0]
-            try:
-                force_update = args[1]
-                using = args[2]
-                update_fields = args[3]
-            except IndexError:
-                pass
 
         self._prepare_related_fields_for_save(operation_name="save")
 
@@ -885,26 +911,14 @@ class Model(AltersData, metaclass=ModelBase):
     ):
         # RemovedInDjango60Warning.
         if args:
-            warnings.warn(
-                "Passing positional arguments to asave() is deprecated",
-                RemovedInDjango60Warning,
-                stacklevel=2,
+            force_insert, force_update, using, update_fields = self._parse_params(
+                *args,
+                method_name="asave",
+                force_insert=force_insert,
+                force_update=force_update,
+                using=using,
+                update_fields=update_fields,
             )
-            total_len_args = len(args) + 1  # include self
-            if total_len_args > 5:
-                # Recreate the proper TypeError message from Python.
-                raise TypeError(
-                    "Model.asave() takes from 1 to 5 positional arguments but "
-                    f"{total_len_args} were given"
-                )
-            force_insert = args[0]
-            try:
-                force_update = args[1]
-                using = args[2]
-                update_fields = args[3]
-            except IndexError:
-                pass
-
         return await sync_to_async(self.save)(
             force_insert=force_insert,
             force_update=force_update,

tests/basic/tests.py

@@ -239,6 +239,23 @@ class ModelInstanceCreationTests(TestCase):
         ):
             a.save(False, False, None, None, None)
 
+    def test_save_conflicting_positional_and_named_arguments(self):
+        a = Article()
+        cases = [
+            ("force_insert", True, [42]),
+            ("force_update", None, [42, 41]),
+            ("using", "some-db", [42, 41, 40]),
+            ("update_fields", ["foo"], [42, 41, 40, 39]),
+        ]
+        for param_name, param_value, args in cases:
+            with self.subTest(param_name=param_name):
+                msg = f"Model.save() got multiple values for argument '{param_name}'"
+                with (
+                    self.assertWarns(RemovedInDjango60Warning),
+                    self.assertRaisesMessage(TypeError, msg),
+                ):
+                    a.save(*args, **{param_name: param_value})
+
     async def test_asave_deprecation(self):
         a = Article(headline="original", pub_date=datetime(2014, 5, 16))
         msg = "Passing positional arguments to asave() is deprecated"
@@ -275,6 +292,23 @@ class ModelInstanceCreationTests(TestCase):
         ):
             await a.asave(False, False, None, None, None)
 
+    async def test_asave_conflicting_positional_and_named_arguments(self):
+        a = Article()
+        cases = [
+            ("force_insert", True, [42]),
+            ("force_update", None, [42, 41]),
+            ("using", "some-db", [42, 41, 40]),
+            ("update_fields", ["foo"], [42, 41, 40, 39]),
+        ]
+        for param_name, param_value, args in cases:
+            with self.subTest(param_name=param_name):
+                msg = f"Model.asave() got multiple values for argument '{param_name}'"
+                with (
+                    self.assertWarns(RemovedInDjango60Warning),
+                    self.assertRaisesMessage(TypeError, msg),
+                ):
+                    await a.asave(*args, **{param_name: param_value})
+
     @ignore_warnings(category=RemovedInDjango60Warning)
     def test_save_positional_arguments(self):
         a = Article.objects.create(headline="original", pub_date=datetime(2014, 5, 16))