Add type name to ValidationError error message

pydantic/dataclasses.py

@@ -44,7 +44,7 @@ def setattr_validate_assignment(self: 'DataclassType', name: str, value: Any) ->
         d.pop(name)
         value, error_ = self.__pydantic_model__.__fields__[name].validate(value, d, loc=name, cls=self.__class__)
         if error_:
-            raise ValidationError([error_])
+            raise ValidationError([error_], self)
 
     object.__setattr__(self, name, value)
 

pydantic/error_wrappers.py

@@ -51,8 +51,9 @@ ErrorList = Union[Sequence[Any], ErrorWrapper]
 class ValidationError(ValueError):
     __slots__ = ('raw_errors',)
 
-    def __init__(self, errors: Sequence[ErrorList]) -> None:
+    def __init__(self, errors: Sequence[ErrorList], obj_or_type: Any) -> None:
         self.raw_errors = errors
+        self.obj_type: Type[Any] = obj_or_type if isinstance(obj_or_type, type) else type(obj_or_type)
 
     @lru_cache()
     def errors(self) -> List[Dict[str, Any]]:
@@ -64,7 +65,10 @@ class ValidationError(ValueError):
     def __str__(self) -> str:
         errors = self.errors()
         no_errors = len(errors)
-        return f'{no_errors} validation error{"" if no_errors == 1 else "s"}\n{display_errors(errors)}'
+        return (
+            f'{no_errors} validation error{"" if no_errors == 1 else "s"} for {self.obj_type.__name__}\n'
+            f'{display_errors(errors)}'
+        )
 
 
 def display_errors(errors: List[Dict[str, Any]]) -> str:

pydantic/main.py

@@ -293,7 +293,7 @@ class BaseModel(metaclass=MetaModel):
         elif self.__config__.validate_assignment:
             value_, error_ = self.fields[name].validate(value, self.dict(exclude={name}), loc=name)
             if error_:
-                raise ValidationError([error_])
+                raise ValidationError([error_], self)
             else:
                 self.__values__[name] = value_
                 self.__fields_set__.add(name)
@@ -372,7 +372,7 @@ class BaseModel(metaclass=MetaModel):
                     obj = dict(obj)
                 except (TypeError, ValueError) as e:
                     exc = TypeError(f'{cls.__name__} expected dict not {type(obj).__name__}')
-                    raise ValidationError([ErrorWrapper(exc, loc='__obj__')]) from e
+                    raise ValidationError([ErrorWrapper(exc, loc='__obj__')], cls) from e
         return cls(**obj)
 
     @classmethod
@@ -390,7 +390,7 @@ class BaseModel(metaclass=MetaModel):
                 b, proto=proto, content_type=content_type, encoding=encoding, allow_pickle=allow_pickle
             )
         except (ValueError, TypeError, UnicodeDecodeError) as e:
-            raise ValidationError([ErrorWrapper(e, loc='__obj__')])
+            raise ValidationError([ErrorWrapper(e, loc='__obj__')], cls)
         return cls.parse_obj(obj)
 
     @classmethod
@@ -784,8 +784,8 @@ def validate_model(  # noqa: C901 (ignore complexity)
                     errors.append(ErrorWrapper(ExtraError(), loc=f, config=config))
 
     if not raise_exc:
-        return values, fields_set, ValidationError(errors) if errors else None
+        return values, fields_set, ValidationError(errors, model) if errors else None
 
     if errors:
-        raise ValidationError(errors)
+        raise ValidationError(errors, model)
     return values, fields_set, None

tests/test_error_wrappers.py

@@ -135,7 +135,7 @@ from pydantic.error_wrappers import ValidationError, flatten_errors, get_exc_typ
         (
             '__str__',
             """\
-11 validation errors
+11 validation errors for Model
 a
   value is not a valid integer (type=type_error.integer)
 b -> x
@@ -227,7 +227,7 @@ def test_single_error():
         Model(x='x')
 
     expected = """\
-1 validation error
+1 validation error for Model
 x
   value is not a valid integer (type=type_error.integer)"""
     assert str(exc_info.value) == expected
@@ -239,7 +239,7 @@ x
     assert (
         str(exc_info.value)
         == """\
-1 validation error
+1 validation error for Model
 x
   field required (type=value_error.missing)"""
     )