Add strict_model_abstract_attrs setting to allow models.Model.objects access (#2830)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: anthony sottile <103459774+asottile-sentry@users.noreply.github.com>

Author: 3 people

README.md

@@ -124,6 +124,14 @@ The supported settings are:
 
   Set to `false` if using dynamic settings, as [described below](https://github.com/typeddjango/django-stubs#how-to-use-a-custom-library-to-handle-django-settings).
 
+- `strict_model_abstract_attrs`, a boolean, default `true`.
+
+  Set to `false` if you want to keep `.objects`, `.DoesNotExist`,
+  and `.MultipleObjectsReturned` attributes on `models.Model` type.
+  [See here why](https://github.com/typeddjango/django-stubs?tab=readme-ov-file#how-to-use-typemodel-annotation-with-objects-attribute)
+  this is dangerous to do by default.
+
+
 ## FAQ
 
 ### Is this an official Django project?
@@ -367,6 +375,11 @@ def assert_zero_count(model_type: type[models.Model]) -> None:
     assert model_type._default_manager.count() == 0
 ```
 
+Configurable with `strict_model_abstract_attrs = false`
+to skip removing `.objects`, `.DoesNotExist`, and `.MultipleObjectsReturned`
+attributes from `model.Model` if you are using our mypy plugin.
+
+Use this setting on your own risk, because it can hide valid errors.
 
 ### How to type a custom `models.Field`?
 

mypy_django_plugin/config.py

@@ -18,6 +18,7 @@
 [mypy.plugins.django-stubs]
 django_settings_module = str (default: `os.getenv("DJANGO_SETTINGS_MODULE")`)
 strict_settings = bool (default: true)
+strict_model_abstract_attrs = bool (default: true)
 ...
 """
 TOML_USAGE = """
@@ -26,14 +27,17 @@
 [tool.django-stubs]
 django_settings_module = str (default: `os.getenv("DJANGO_SETTINGS_MODULE")`)
 strict_settings = bool (default: true)
+strict_model_abstract_attrs = bool (default: true)
 ...
 """
 INVALID_FILE = "mypy config file is not specified or found"
 COULD_NOT_LOAD_FILE = "could not load configuration file"
 MISSING_SECTION = "no section [{section}] found"
 DJANGO_SETTINGS_ENV_VAR = "DJANGO_SETTINGS_MODULE"
-MISSING_DJANGO_SETTINGS = f"missing required 'django_settings_module' config.\
- Either specify this config or set your `{DJANGO_SETTINGS_ENV_VAR}` env var"
+MISSING_DJANGO_SETTINGS = (
+    "missing required 'django_settings_module' config.\n"
+    f"Either specify this config or set your `{DJANGO_SETTINGS_ENV_VAR}` env var"
+)
 INVALID_BOOL_SETTING = "invalid {key!r}: the setting must be a boolean"
 
 
@@ -54,7 +58,8 @@ def exit_with_error(msg: str, is_toml: bool = False) -> NoReturn:
 
 
 class DjangoPluginConfig:
-    __slots__ = ("django_settings_module", "strict_settings")
+    __slots__ = ("django_settings_module", "strict_settings", "strict_model_abstract_attrs")
+
     django_settings_module: str
     strict_settings: bool
 
@@ -96,6 +101,9 @@ def parse_toml_file(self, filepath: Path) -> None:
         self.strict_settings = config.get("strict_settings", True)
         if not isinstance(self.strict_settings, bool):
             toml_exit(INVALID_BOOL_SETTING.format(key="strict_settings"))
+        self.strict_model_abstract_attrs = config.get("strict_model_abstract_attrs", True)
+        if not isinstance(self.strict_model_abstract_attrs, bool):
+            toml_exit(INVALID_BOOL_SETTING.format(key="strict_model_abstract_attrs"))
 
     def parse_ini_file(self, filepath: Path) -> None:
         parser = configparser.ConfigParser()
@@ -124,10 +132,16 @@ def parse_ini_file(self, filepath: Path) -> None:
         except ValueError:
             exit_with_error(INVALID_BOOL_SETTING.format(key="strict_settings"))
 
+        try:
+            self.strict_model_abstract_attrs = parser.getboolean(section, "strict_model_abstract_attrs", fallback=True)
+        except ValueError:
+            exit_with_error(INVALID_BOOL_SETTING.format(key="strict_model_abstract_attrs"))
+
     def to_json(self, extra_data: dict[str, Any]) -> dict[str, Any]:
         """We use this method to reset mypy cache via `report_config_data` hook."""
         return {
             "django_settings_module": self.django_settings_module,
             "strict_settings": self.strict_settings,
+            "strict_model_abstract_attrs": self.strict_model_abstract_attrs,
             **dict(sorted(extra_data.items())),
         }

mypy_django_plugin/main.py

@@ -212,7 +212,7 @@ def get_customize_class_mro_hook(self, fullname: str) -> Callable[[ClassDefConte
 
     def get_metaclass_hook(self, fullname: str) -> Callable[[ClassDefContext], None] | None:
         if fullname == fullnames.MODEL_METACLASS_FULLNAME:
-            return MetaclassAdjustments.adjust_model_class
+            return partial(MetaclassAdjustments.adjust_model_class, plugin_config=self.plugin_config)
         return None
 
     def get_base_class_hook(self, fullname: str) -> Callable[[ClassDefContext], None] | None:
@@ -292,11 +292,9 @@ def get_dynamic_class_hook(self, fullname: str) -> Callable[[DynamicClassDefCont
 
     def report_config_data(self, ctx: ReportConfigContext) -> dict[str, Any]:
         # Cache would be cleared if any settings do change.
-        extra_data = {}
-        # In all places we use '_User' alias as a type we want to clear cache if
-        # AUTH_USER_MODEL setting changes
-        if ctx.id.startswith("django.contrib.auth") or ctx.id in {"django.http.request", "django.test.client"}:
-            extra_data["AUTH_USER_MODEL"] = self.django_context.settings.AUTH_USER_MODEL
+        extra_data = {
+            "AUTH_USER_MODEL": self.django_context.settings.AUTH_USER_MODEL,
+        }
         return self.plugin_config.to_json(extra_data)
 
 

mypy_django_plugin/transformers/models.py

@@ -40,6 +40,7 @@
 from mypy.types import Type as MypyType
 from mypy.typevars import fill_typevars, fill_typevars_with_any
 
+from mypy_django_plugin.config import DjangoPluginConfig
 from mypy_django_plugin.django.context import DjangoContext
 from mypy_django_plugin.errorcodes import MANAGER_MISSING
 from mypy_django_plugin.exceptions import UnregisteredModelError
@@ -991,13 +992,35 @@ def create_many_related_manager(self, model: Instance) -> None:
 
 class MetaclassAdjustments(ModelClassInitializer):
     @classmethod
-    def adjust_model_class(cls, ctx: ClassDefContext) -> None:
+    def adjust_model_class(cls, ctx: ClassDefContext, plugin_config: DjangoPluginConfig) -> None:
         """
         For the sake of type checkers other than mypy, some attributes that are
         dynamically added by Django's model metaclass has been annotated on
         `django.db.models.base.Model`. We remove those attributes and will handle them
         through the plugin.
+
+        Configurable with `strict_model_abstract_attrs = false` to skip removing any objects from models.
+
+        Basically, this code::
+
+            from django.db import models
+
+            def get_model_count(model_type: type[models.Model]) -> int:
+                return model_type.objects.count()
+
+        - Will raise an error
+          `"type[models.Model]" has no attribute "objects"  [attr-defined]`
+          when `strict_model_abstract_attrs = true` (default)
+        - Return without any type errors
+          when `strict_model_abstract_attrs = false`
+
+        But, beware that the code above can fail in runtime, as mypy correctly shows.
+        Example: `get_model_count(models.Model)`
+
+        Turn this setting off at your own risk.
         """
+        if not plugin_config.strict_model_abstract_attrs:
+            return
         if ctx.cls.fullname != fullnames.MODEL_CLASS_FULLNAME:
             return
 
@@ -1006,8 +1029,6 @@ def adjust_model_class(cls, ctx: ClassDefContext) -> None:
             if attr is not None and isinstance(attr.node, Var) and not attr.plugin_generated:
                 del ctx.cls.info.names[attr_name]
 
-        return
-
     def get_exception_bases(self, name: str) -> list[Instance]:
         bases = []
         for model_base in self.model_classdef.info.direct_base_classes():

tests/test_error_handling.py

@@ -16,6 +16,7 @@
 [mypy.plugins.django-stubs]
 django_settings_module = str (default: `os.getenv("DJANGO_SETTINGS_MODULE")`)
 strict_settings = bool (default: true)
+strict_model_abstract_attrs = bool (default: true)
 ...
 (django-stubs) mypy: error: {}
 """
@@ -26,6 +27,7 @@
 [tool.django-stubs]
 django_settings_module = str (default: `os.getenv("DJANGO_SETTINGS_MODULE")`)
 strict_settings = bool (default: true)
+strict_model_abstract_attrs = bool (default: true)
 ...
 (django-stubs) mypy: error: {}
 """
@@ -49,20 +51,33 @@ def write_to_file(file_contents: str, suffix: str | None = None) -> Generator[st
         ),
         pytest.param(
             ["[mypy.plugins.django-stubs]", "\tnot_django_not_settings_module = badbadmodule"],
-            "missing required 'django_settings_module' config.\
- Either specify this config or set your `DJANGO_SETTINGS_MODULE` env var",
+            (
+                "missing required 'django_settings_module' config.\n"
+                "Either specify this config or set your `DJANGO_SETTINGS_MODULE` env var"
+            ),
             id="missing-settings-module",
         ),
         pytest.param(
             ["[mypy.plugins.django-stubs]"],
-            "missing required 'django_settings_module' config.\
- Either specify this config or set your `DJANGO_SETTINGS_MODULE` env var",
+            (
+                "missing required 'django_settings_module' config.\n"
+                "Either specify this config or set your `DJANGO_SETTINGS_MODULE` env var"
+            ),
             id="no-settings-given",
         ),
         pytest.param(
             ["[mypy.plugins.django-stubs]", "django_settings_module = some.module", "strict_settings = bad"],
             "invalid 'strict_settings': the setting must be a boolean",
-            id="missing-settings-module",
+            id="invalid-strict_settings",
+        ),
+        pytest.param(
+            [
+                "[mypy.plugins.django-stubs]",
+                "django_settings_module = some.module",
+                "strict_model_abstract_attrs = bad",
+            ],
+            "invalid 'strict_model_abstract_attrs': the setting must be a boolean",
+            id="invalid-strict_model_abstract_attrs",
         ),
     ],
 )
@@ -117,8 +132,10 @@ def test_handles_filename(capsys: Any, filename: str) -> None:
             [tool.django-stubs]
             not_django_not_settings_module = "badbadmodule"
             """,
-            "missing required 'django_settings_module' config.\
- Either specify this config or set your `DJANGO_SETTINGS_MODULE` env var",
+            (
+                "missing required 'django_settings_module' config.\n"
+                "Either specify this config or set your `DJANGO_SETTINGS_MODULE` env var"
+            ),
             id="missing django_settings_module",
         ),
         pytest.param(
@@ -135,6 +152,15 @@ def test_handles_filename(capsys: Any, filename: str) -> None:
             "invalid 'strict_settings': the setting must be a boolean",
             id="invalid strict_settings type",
         ),
+        pytest.param(
+            """
+            [tool.django-stubs]
+            django_settings_module = "some.module"
+            strict_model_abstract_attrs = "a"
+            """,
+            "invalid 'strict_model_abstract_attrs': the setting must be a boolean",
+            id="invalid strict_model_abstract_attrs type",
+        ),
     ],
 )
 def test_toml_misconfiguration_handling(capsys: Any, config_file_contents: str, message_part: str) -> None: