revalidate models (#177)

* revaliate models

* fields_set and tests

pydantic_core/_types.py

@@ -37,6 +37,7 @@ class Config(TypedDict, total=False):
     typed_dict_populate_by_name: bool  # replaces `allow_population_by_field_name` in pydantic v1
     # used on typed-dicts and tagged union keys
     from_attributes: bool
+    revalidate_models: bool
     # fields related to string fields only
     str_max_length: int
     str_min_length: int

src/build_tools.rs

@@ -29,6 +29,7 @@ impl<'py> SchemaDict<'py> for PyDict {
         }
     }
 
+    #[cfg_attr(has_no_coverage, no_coverage)]
     fn get_as_req<T>(&'py self, key: &str) -> PyResult<T>
     where
         T: FromPyObject<'py>,
@@ -40,6 +41,28 @@ impl<'py> SchemaDict<'py> for PyDict {
     }
 }
 
+impl<'py> SchemaDict<'py> for Option<&PyDict> {
+    fn get_as<T>(&'py self, key: &str) -> PyResult<Option<T>>
+    where
+        T: FromPyObject<'py>,
+    {
+        match self {
+            Some(d) => d.get_as(key),
+            None => Ok(None),
+        }
+    }
+
+    fn get_as_req<T>(&'py self, key: &str) -> PyResult<T>
+    where
+        T: FromPyObject<'py>,
+    {
+        match self {
+            Some(d) => d.get_as_req(key),
+            None => py_error!(PyKeyError; "{}", key),
+        }
+    }
+}
+
 pub fn schema_or_config<'py, T>(
     schema: &'py PyDict,
     config: Option<&'py PyDict>,

src/input/input_abstract.rs

@@ -1,7 +1,7 @@
 use std::fmt;
 
 use pyo3::prelude::*;
-use pyo3::types::PyType;
+use pyo3::types::{PyString, PyType};
 
 use crate::errors::{InputValue, LocItem, ValResult};
 use crate::input::datetime::EitherTime;
@@ -29,6 +29,11 @@ pub trait Input<'a>: fmt::Debug + ToPyObject {
         Ok(false)
     }
 
+    #[cfg_attr(has_no_coverage, no_coverage)]
+    fn get_attr(&self, _name: &PyString) -> Option<&PyAny> {
+        None
+    }
+
     fn is_instance(&self, _class: &PyType) -> PyResult<bool> {
         Ok(false)
     }

src/input/input_python.rs

@@ -48,6 +48,10 @@ impl<'a> Input<'a> for PyAny {
         Ok(self.get_type().eq(class)?)
     }
 
+    fn get_attr(&self, name: &PyString) -> Option<&PyAny> {
+        self.getattr(name).ok()
+    }
+
     fn is_instance(&self, class: &PyType) -> PyResult<bool> {
         self.is_instance(class)
     }

src/validators/mod.rs

@@ -367,7 +367,7 @@ impl<'a> Extra<'a> {
 #[enum_dispatch]
 pub enum CombinedValidator {
     // typed dict e.g. heterogeneous dicts or simply a model
-    Model(typed_dict::TypedDictValidator),
+    TypedDict(typed_dict::TypedDictValidator),
     // unions
     Union(union::UnionValidator),
     TaggedUnion(union::TaggedUnionValidator),

src/validators/model_class.rs

@@ -13,12 +13,14 @@ use crate::errors::{ErrorKind, ValError, ValResult};
 use crate::input::Input;
 use crate::recursion_guard::RecursionGuard;
 
+use super::typed_dict::TypedDictValidator;
 use super::{build_validator, BuildContext, BuildValidator, CombinedValidator, Extra, Validator};
 
 #[derive(Debug, Clone)]
 pub struct ModelClassValidator {
     strict: bool,
-    validator: Box<CombinedValidator>,
+    revalidate: bool,
+    validator: TypedDictValidator,
     class: Py<PyType>,
     name: String,
 }
@@ -36,17 +38,23 @@ impl BuildValidator for ModelClassValidator {
 
         let class: &PyType = schema.get_as_req("class_type")?;
         let sub_schema: &PyAny = schema.get_as_req("schema")?;
-        let (validator, td_schema) = build_validator(sub_schema, config, build_context)?;
+        let (comb_validator, td_schema) = build_validator(sub_schema, config, build_context)?;
 
         if !td_schema.get_as("return_fields_set")?.unwrap_or(false) {
-            return py_error!(r#"model-class inner schema must have "return_fields_set" set to True"#);
+            return py_error!("model-class inner schema must have 'return_fields_set' set to True");
         }
 
+        let validator = match comb_validator {
+            CombinedValidator::TypedDict(tdv) => tdv,
+            _ => return py_error!("Wrong validator type, expected 'typed-dict' validator"),
+        };
+
         Ok(Self {
             // we don't use is_strict here since we don't want validation to be strict in this case if
             // `config.strict` is set, only if this specific field is strict
             strict: schema.get_as("strict")?.unwrap_or(false),
-            validator: Box::new(validator),
+            revalidate: config.get_as("revalidate_models")?.unwrap_or(false),
+            validator,
             class: class.into(),
             // Get the class's `__name__`, not using `class.name()` since it uses `__qualname__`
             // which is not what we want here
@@ -67,7 +75,15 @@ impl Validator for ModelClassValidator {
     ) -> ValResult<'data, PyObject> {
         let class = self.class.as_ref(py);
         if input.is_type(class)? {
-            Ok(input.to_object(py))
+            if self.revalidate {
+                let fields_set = input.get_attr(intern!(py, "__fields_set__"));
+                let output = self.validator.validate(py, input, extra, slots, recursion_guard)?;
+                let (model_dict, validation_fields_set): (&PyAny, &PyAny) = output.extract(py)?;
+                let fields_set = fields_set.unwrap_or(validation_fields_set);
+                Ok(self.create_class(py, model_dict, fields_set)?)
+            } else {
+                Ok(input.to_object(py))
+            }
         } else if extra.strict.unwrap_or(self.strict) {
             Err(ValError::new(
                 ErrorKind::ModelClassType {
@@ -77,7 +93,8 @@ impl Validator for ModelClassValidator {
             ))
         } else {
             let output = self.validator.validate(py, input, extra, slots, recursion_guard)?;
-            Ok(self.create_class(py, output)?)
+            let (model_dict, fields_set): (&PyAny, &PyAny) = output.extract(py)?;
+            Ok(self.create_class(py, model_dict, fields_set)?)
         }
     }
 
@@ -87,9 +104,7 @@ impl Validator for ModelClassValidator {
 }
 
 impl ModelClassValidator {
-    fn create_class(&self, py: Python, output: PyObject) -> PyResult<PyObject> {
-        let (model_dict, fields_set): (&PyAny, &PyAny) = output.extract(py)?;
-
+    fn create_class(&self, py: Python, model_dict: &PyAny, fields_set: &PyAny) -> PyResult<PyObject> {
         // based on the following but with the second argument of new_func set to an empty tuple as required
         // https://github.com/PyO3/pyo3/blob/d2caa056e9aacc46374139ef491d112cb8af1a25/src/pyclass_init.rs#L35-L77
         let args = PyTuple::empty(py);

tests/validators/test_model_class.py

@@ -118,7 +118,7 @@ def test_not_return_fields_set():
     class MyModel:
         pass
 
-    with pytest.raises(SchemaError, match='model-class inner schema must have "return_fields_set" set to True'):
+    with pytest.raises(SchemaError, match="model-class inner schema must have 'return_fields_set' set to True"):
         SchemaValidator(
             {
                 'type': 'model-class',
@@ -212,6 +212,7 @@ def __init__(self):
             },
         }
     )
+    assert re.search(r'revalidate: \w+', repr(v)).group(0) == 'revalidate: false'
     m = MyModel()
     m2 = v.validate_python(m)
     assert isinstance(m, MyModel)
@@ -243,3 +244,87 @@ def test_internal_error():
     )
     with pytest.raises(AttributeError, match=re.escape("'int' object has no attribute '__dict__'")):
         v.validate_python({'f': 123})
+
+
+def test_revalidate():
+    class MyModel:
+        __slots__ = '__dict__', '__fields_set__'
+
+        def __init__(self, a, b, fields_set):
+            self.field_a = a
+            self.field_b = b
+            self.__fields_set__ = fields_set
+
+    v = SchemaValidator(
+        {
+            'type': 'model-class',
+            'class_type': MyModel,
+            'schema': {
+                'type': 'typed-dict',
+                'return_fields_set': True,
+                'from_attributes': True,
+                'fields': {'field_a': {'schema': {'type': 'str'}}, 'field_b': {'schema': {'type': 'int'}}},
+            },
+            'config': {'revalidate_models': True},
+        }
+    )
+    assert re.search(r'revalidate: \w+', repr(v)).group(0) == 'revalidate: true'
+
+    m = v.validate_python({'field_a': 'test', 'field_b': 12})
+    assert isinstance(m, MyModel)
+    assert m.__dict__ == {'field_a': 'test', 'field_b': 12}
+    assert m.__fields_set__ == {'field_a', 'field_b'}
+
+    m2 = MyModel('x', 42, {'field_a'})
+    m3 = v.validate_python(m2)
+    assert isinstance(m3, MyModel)
+    assert m3 is not m2
+    assert m3.__dict__ == {'field_a': 'x', 'field_b': 42}
+    assert m3.__fields_set__ == {'field_a'}
+
+    m4 = MyModel('x', 'not int', {'field_a'})
+    with pytest.raises(ValidationError) as exc_info:
+        v.validate_python(m4)
+    assert exc_info.value.errors() == [
+        {
+            'kind': 'int_parsing',
+            'loc': ['field_b'],
+            'message': 'Value must be a valid integer, unable to parse string as an integer',
+            'input_value': 'not int',
+        }
+    ]
+
+
+def test_revalidate_extra():
+    class MyModel:
+        __slots__ = '__dict__', '__fields_set__'
+
+        def __init__(self, **kwargs):
+            self.__dict__.update(kwargs)
+
+    v = SchemaValidator(
+        {
+            'type': 'model-class',
+            'class_type': MyModel,
+            'schema': {
+                'type': 'typed-dict',
+                'return_fields_set': True,
+                'from_attributes': True,
+                'extra_behavior': 'allow',
+                'fields': {'field_a': {'schema': {'type': 'str'}}, 'field_b': {'schema': {'type': 'int'}}},
+            },
+            'config': {'revalidate_models': True},
+        }
+    )
+
+    m = v.validate_python({'field_a': 'test', 'field_b': 12, 'more': (1, 2, 3)})
+    assert isinstance(m, MyModel)
+    assert m.__dict__ == {'field_a': 'test', 'field_b': 12, 'more': (1, 2, 3)}
+    assert m.__fields_set__ == {'field_a', 'field_b', 'more'}
+
+    m2 = MyModel(field_a='x', field_b=42, another=42.5)
+    m3 = v.validate_python(m2)
+    assert isinstance(m3, MyModel)
+    assert m3 is not m2
+    assert m3.__dict__ == {'field_a': 'x', 'field_b': 42, 'another': 42.5}
+    assert m3.__fields_set__ == {'field_a', 'field_b', 'another'}

tests/validators/test_typed_dict.py

@@ -534,7 +534,7 @@ def test_aliases_debug():
     v = SchemaValidator(
         {'type': 'typed-dict', 'fields': {'field_a': {'alias': [['foo', 'bar', 'bat'], ['foo', 3]], 'schema': 'int'}}}
     )
-    assert repr(v).startswith('SchemaValidator(name="typed-dict", validator=Model(')
+    assert repr(v).startswith('SchemaValidator(name="typed-dict", validator=TypedDict(')
     assert 'PathChoices(' in repr(v)