Add warnings/errors for non-annotated fields (#5263)

* Add warnings/errors for non-annotated fields

* Fix docs tests

* Change error message

* Change non_field_types to ignored_types

* Update test name

* Address feedback

docs/usage/model_config.md

@@ -151,9 +151,10 @@ for validation, for use with `from_attributes`; see [Data binding](models.md#dat
 **`alias_generator`**
 : a callable that takes a field name and returns an alias for it; see [the dedicated section](#alias-generator)
 
-**`keep_untouched`**
-: a tuple of types (e.g. descriptors) for a model's default values that should not be changed during model creation and will
-not be included in the model schemas. **Note**: this means that attributes on the model with *defaults of this type*, not *annotations of this type*, will be left alone.
+**`ignored_types`**
+: a tuple of types that may occur as values of class attributes without annotations; this is typically used for
+custom descriptors (classes that behave like `property`). If an attribute is set on a class without an annotation
+and has a type that is not in this tuple (or otherwise recognized by pydantic), an error will be raised.
 
 **`schema_extra`**
 : a `dict` used to extend/update the generated JSON Schema, or a callable to post-process it; see [schema customization](schema.md#schema-customization)

docs/usage/models.md

@@ -140,8 +140,8 @@ class Foo(BaseModel):
 
 
 class Bar(BaseModel):
-    apple = 'x'
-    banana = 'y'
+    apple: str = 'x'
+    banana: str = 'y'
 
 
 class Spam(BaseModel):
@@ -151,9 +151,16 @@ class Spam(BaseModel):
 
 m = Spam(foo={'count': 4}, bars=[{'apple': 'x1'}, {'apple': 'x2'}])
 print(m)
-#> foo=Foo(count=4, size=None) bars=[Bar(), Bar()]
+"""
+foo=Foo(count=4, size=None) bars=[Bar(apple='x1', banana='y'), Bar(apple='x2', banana='y')]
+"""
 print(m.model_dump())
-#> {'foo': {'count': 4, 'size': None}, 'bars': [{}, {}]}
+"""
+{
+    'foo': {'count': 4, 'size': None},
+    'bars': [{'apple': 'x1', 'banana': 'y'}, {'apple': 'x2', 'banana': 'y'}],
+}
+"""
 ```
 
 For self-referencing models, see [postponed annotations](postponed_annotations.md#self-referencing-models).
@@ -409,8 +416,8 @@ from pydantic import BaseModel, ValidationError, conint
 
 
 class Location(BaseModel):
-    lat = 0.1
-    lng = 10.1
+    lat: float = 0.1
+    lng: float = 10.1
 
 
 class Model(BaseModel):
@@ -433,7 +440,7 @@ try:
 except ValidationError as e:
     print(e)
     """
-    4 validation errors for Location
+    5 validation errors for Location
     is_required
       Field required [type=missing, input_value={'list_of_ints': ['1', 2,...ew York'}, 'gt_int': 21}, input_type=dict]
     gt_int
@@ -442,6 +449,8 @@ except ValidationError as e:
       Input should be a valid integer, unable to parse string as an integer [type=int_parsing, input_value='bad', input_type=str]
     a_float
       Input should be a valid number, unable to parse string as an number [type=float_parsing, input_value='not a float', input_type=str]
+    recursive_model -> lng
+      Input should be a valid number, unable to parse string as an number [type=float_parsing, input_value='New York', input_type=str]
     """
 
 try:
@@ -482,6 +491,12 @@ except ValidationError as e:
             'msg': 'Input should be a valid number, unable to parse string as an number',
             'input': 'not a float',
         },
+        {
+            'type': 'float_parsing',
+            'loc': ('recursive_model', 'lng'),
+            'msg': 'Input should be a valid number, unable to parse string as an number',
+            'input': 'New York',
+        },
     ]
     """
 ```
@@ -580,13 +595,13 @@ from pydantic import BaseModel, ValidationError
 
 class User(BaseModel):
     id: int
-    name = 'John Doe'
+    name: str = 'John Doe'
     signup_ts: datetime = None
 
 
 m = User.model_validate({'id': 123, 'name': 'James'})
 print(m)
-#> id=123 signup_ts=None
+#> id=123 name='James' signup_ts=None
 
 try:
     User.model_validate(['not', 'a', 'dict'])
@@ -600,7 +615,7 @@ except ValidationError as e:
 # assumes json as no content type passed
 m = User.model_validate_json('{"id": 123, "name": "James"}')
 print(m)
-#> id=123 signup_ts=None
+#> id=123 name='James' signup_ts=None
 ```
 
 !!! warning
@@ -902,7 +917,7 @@ the `create_model` method to allow models to be created on the fly.
 ```py
 from pydantic import BaseModel, create_model
 
-DynamicFoobarModel = create_model('DynamicFoobarModel', foo=(str, ...), bar=123)
+DynamicFoobarModel = create_model('DynamicFoobarModel', foo=(str, ...), bar=(int, 123))
 
 
 class StaticFoobarModel(BaseModel):
@@ -932,14 +947,14 @@ class FooModel(BaseModel):
 
 BarModel = create_model(
     'BarModel',
-    apple='russet',
-    banana='yellow',
+    apple=(str, 'russet'),
+    banana=(str, 'yellow'),
     __base__=FooModel,
 )
 print(BarModel)
 #> <class 'pydantic.main.BarModel'>
 print(BarModel.model_fields.keys())
-#> dict_keys(['foo', 'bar'])
+#> dict_keys(['foo', 'bar', 'apple', 'banana'])
 ```
 
 You can also add validators by passing a dict to the `__validators__` argument.
@@ -1167,24 +1182,24 @@ from pydantic import BaseModel, ValidationError
 
 class Model(BaseModel):
     a: int
-    b = 2
+    b: int = 2
     c: int = 1
-    d = 0
+    d: int = 0
     e: float
 
 
 print(Model.model_fields.keys())
-#> dict_keys(['a', 'c', 'e'])
+#> dict_keys(['a', 'b', 'c', 'd', 'e'])
 m = Model(e=2, a=1)
 print(m.model_dump())
-#> {'a': 1, 'c': 1, 'e': 2.0}
+#> {'a': 1, 'b': 2, 'c': 1, 'd': 0, 'e': 2.0}
 try:
     Model(a='x', b='x', c='x', d='x', e='x')
 except ValidationError as err:
     error_locations = [e['loc'] for e in err.errors()]
 
 print(error_locations)
-#> [('a',), ('c',), ('e',)]
+#> [('a',), ('b',), ('c',), ('d',), ('e',)]
 ```
 
 !!! warning

pydantic/_internal/_model_construction.py

@@ -4,7 +4,6 @@
 from __future__ import annotations as _annotations
 
 import typing
-import warnings
 from functools import partial
 from types import FunctionType
 from typing import Any, Callable
@@ -15,6 +14,7 @@
 from ..fields import FieldInfo, ModelPrivateAttr, PrivateAttr
 from ._core_metadata import build_metadata_dict
 from ._core_utils import consolidate_refs, define_expected_missing_refs
+from ._decorators import PydanticDecoratorMarker
 from ._fields import Undefined, collect_fields
 from ._forward_ref import PydanticForwardRef
 from ._generate_schema import generate_config, get_model_self_schema, model_fields_schema
@@ -30,8 +30,7 @@
 
 __all__ = 'object_setattr', 'init_private_attributes', 'inspect_namespace', 'complete_model_class', 'MockValidator'
 
-
-IGNORED_TYPES: tuple[Any, ...] = (FunctionType, property, type, classmethod, staticmethod)
+IGNORED_TYPES: tuple[Any, ...] = (FunctionType, property, type, classmethod, staticmethod, PydanticDecoratorMarker)
 object_setattr = object.__setattr__
 
 
@@ -47,16 +46,30 @@ def init_private_attributes(self_: Any, _context: Any) -> None:
             object_setattr(self_, name, default)
 
 
-def inspect_namespace(namespace: dict[str, Any]) -> dict[str, ModelPrivateAttr]:
+def inspect_namespace(  # noqa C901
+    namespace: dict[str, Any],
+    ignored_types: tuple[type[Any], ...],
+    base_class_vars: set[str],
+    base_class_fields: set[str],
+) -> dict[str, ModelPrivateAttr]:
     """
     iterate over the namespace and:
     * gather private attributes
     * check for items which look like fields but are not (e.g. have no annotation) and warn
     """
+    all_ignored_types = ignored_types + IGNORED_TYPES
+
     private_attributes: dict[str, ModelPrivateAttr] = {}
     raw_annotations = namespace.get('__annotations__', {})
+
+    ignored_names: set[str] = set()
     for var_name, value in list(namespace.items()):
-        if isinstance(value, ModelPrivateAttr):
+        if var_name == 'model_config':
+            continue
+        elif isinstance(value, all_ignored_types):
+            ignored_names.add(var_name)
+            continue
+        elif isinstance(value, ModelPrivateAttr):
             if var_name.startswith('__'):
                 raise NameError(
                     f'Private attributes "{var_name}" must not have dunder names; '
@@ -69,22 +82,37 @@ def inspect_namespace(namespace: dict[str, Any]) -> dict[str, ModelPrivateAttr]:
                 )
             private_attributes[var_name] = value
             del namespace[var_name]
-        elif not single_underscore(var_name):
+        elif var_name.startswith('__'):
             continue
         elif var_name.startswith('_'):
-            if var_name in raw_annotations and is_classvar(raw_annotations[var_name]):
-                continue
-            private_attributes[var_name] = PrivateAttr(default=value)
-            del namespace[var_name]
-        elif var_name not in raw_annotations and not isinstance(value, IGNORED_TYPES):
-            warnings.warn(
-                f'All fields must include a type annotation; '
-                f'{var_name!r} looks like a field but has no type annotation.',
-                DeprecationWarning,
-            )
+            if var_name in raw_annotations and not is_classvar(raw_annotations[var_name]):
+                private_attributes[var_name] = PrivateAttr(default=value)
+                del namespace[var_name]
+        elif var_name in base_class_vars:
+            continue
+        elif var_name not in raw_annotations:
+            if var_name in base_class_fields:
+                raise PydanticUserError(
+                    f'Field {var_name!r} defined on a base class was overridden by a non-annotated attribute. '
+                    f'All field definitions, including overrides, require a type annotation.',
+                )
+            elif isinstance(value, FieldInfo):
+                raise PydanticUserError(f'Field {var_name!r} requires a type annotation')
+            else:
+                raise PydanticUserError(
+                    f'A non-annotated attribute was detected: `{var_name} = {value!r}`. All model fields require a '
+                    f'type annotation; if {var_name!r} is not meant to be a field, you may be able to resolve this '
+                    f'error by annotating it as a ClassVar or updating model_config["ignored_types"].',
+                )
 
     for ann_name, ann_type in raw_annotations.items():
-        if single_underscore(ann_name) and ann_name not in private_attributes and not is_classvar(ann_type):
+        if (
+            single_underscore(ann_name)
+            and ann_name not in private_attributes
+            and ann_name not in ignored_names
+            and not is_classvar(ann_type)
+            and ann_type not in all_ignored_types
+        ):
             private_attributes[ann_name] = PrivateAttr()
 
     return private_attributes

pydantic/config.py

@@ -60,7 +60,7 @@ class _ConfigDict(TypedDict, total=False):
     undefined_types_warning: bool  # TODO review docs
     from_attributes: bool
     alias_generator: Callable[[str], str] | None
-    keep_untouched: tuple[type, ...]  # TODO remove??
+    ignored_types: tuple[type, ...]  # TODO remove??
     json_loads: Callable[[str], Any]  # TODO decide
     json_dumps: Callable[..., str]  # TODO decide
     json_encoders: dict[type[Any] | str | ForwardRef, Callable[..., Any]]  # TODO decide
@@ -112,7 +112,7 @@ def __missing__(self, key: str) -> Any:
     undefined_types_warning=True,
     from_attributes=False,
     alias_generator=None,
-    keep_untouched=(),
+    ignored_types=(),
     json_loads=json.loads,
     json_dumps=json.dumps,
     json_encoders={},

pydantic/main.py

@@ -70,10 +70,13 @@ def __new__(
         **kwargs: Any,
     ) -> type:
         if _base_class_defined:
-            class_vars: set[str] = set()
+            base_field_names, class_vars, base_private_attributes = _collect_bases_data(bases)
+
             config_new = build_config(cls_name, bases, namespace, kwargs)
             namespace['model_config'] = config_new
-            private_attributes = _model_construction.inspect_namespace(namespace)
+            private_attributes = _model_construction.inspect_namespace(
+                namespace, config_new.get('ignored_types', ()), class_vars, base_field_names
+            )
             if private_attributes:
                 slots: set[str] = set(namespace.get('__slots__', ()))
                 namespace['__slots__'] = slots | private_attributes.keys()
@@ -93,11 +96,6 @@ def __pydantic_post_init__(self_: Any, context: Any) -> None:
             elif 'model_post_init' in namespace:
                 namespace['__pydantic_post_init__'] = namespace['model_post_init']
 
-            base_private_attributes: dict[str, ModelPrivateAttr] = {}
-            for base in bases:
-                if _base_class_defined and issubclass(base, BaseModel) and base != BaseModel:
-                    base_private_attributes.update(base.__private_attributes__)
-                    class_vars.update(base.__class_vars__)
             namespace['__class_vars__'] = class_vars
             namespace['__private_attributes__'] = {**base_private_attributes, **private_attributes}
 
@@ -134,6 +132,14 @@ def hash_func(self_: Any) -> int:
             )
 
             cls.__pydantic_model_complete__ = False  # Ensure this specific class gets completed
+
+            # preserve `__set_name__` protocol defined in https://peps.python.org/pep-0487
+            # for attributes not in `new_namespace` (e.g. private attributes)
+            for name, obj in private_attributes.items():
+                set_name = getattr(obj, '__set_name__', None)
+                if callable(set_name):
+                    set_name(cls, name)
+
             _model_construction.complete_model_class(
                 cls,
                 cls_name,
@@ -982,3 +988,16 @@ def __init__(self, __type: Any, *, config: CoreConfig | None = None) -> None:
 
     def __call__(self, __input: Any) -> T:
         return self._validator.validate_python(__input)
+
+
+def _collect_bases_data(bases: tuple[type[Any], ...]) -> tuple[set[str], set[str], dict[str, ModelPrivateAttr]]:
+    field_names: set[str] = set()
+    class_vars: set[str] = set()
+    private_attributes: dict[str, ModelPrivateAttr] = {}
+    for base in bases:
+        if _base_class_defined and issubclass(base, BaseModel) and base != BaseModel:
+            # model_fields might not be defined yet in the case of generics, so we use getattr here:
+            field_names.update(getattr(base, 'model_fields', {}).keys())
+            class_vars.update(base.__class_vars__)
+            private_attributes.update(base.__private_attributes__)
+    return field_names, class_vars, private_attributes

pydantic/mypy.py

@@ -463,8 +463,8 @@ def collect_field_from_stmt(self, stmt: Statement, model_config: ModelConfigData
                 and stmt.rvalue.callee.callee.fullname in DECORATOR_FULLNAMES
             ):
                 # This is a (possibly-reused) validator or serializer, not a field
-                # TODO: We may want to inspect whatever replaces keep_untouched in the config
                 # In particular, it looks something like: my_validator = validator('my_field', allow_reuse=True)(f)
+                # Eventually, we may want to attempt to respect model_config['ignored_types']
                 return None
 
             # The assignment does not have an annotation, and it's not anything else we recognize

tests/test_aliases.py

@@ -37,16 +37,6 @@ class MyModel(BaseModel):
     assert str(e.value) == IsStr(regex="alias_generator <function .*> must return str, not <class 'bytes'>")
 
 
-@pytest.mark.xfail(reason='working on V2')
-def test_cannot_infer_type_with_alias():
-    # TODO: I don't think we've finalized the exact error that should be raised when fields are missing annotations,
-    #   but this test should be made consistent with that once it is finalized
-    with pytest.raises(TypeError):
-
-        class Model(BaseModel):
-            a = Field('foobar', alias='_a')
-
-
 def test_basic_alias():
     class Model(BaseModel):
         a: str = Field('foobar', alias='_a')
@@ -112,7 +102,7 @@ class Parent(BaseModel):
         x: int = Field(alias='x1', gt=0)
 
     class Child(Parent):
-        x = Field(..., alias='x2')
+        x: int = Field(..., alias='x2')
         y: int = Field(..., alias='y2')
 
     assert Parent.model_fields['x'].alias == 'x1'