Change ValidationError serialization to {"loc": [], "msg": ""} (#163)

README.md

@@ -65,8 +65,8 @@ assert serialize(Resource, resource) == data
 # Validate during deserialization
 with raises(ValidationError) as err:  # pytest checks exception is raised
     deserialize(Resource, {"id": "42", "name": "wyfo"})
-assert serialize(err.value) == [  # ValidationError is serializable
-    {"loc": ["id"], "err": ["badly formed hexadecimal UUID string"]}
+assert err.value.errors == [
+    {"loc": ["id"], "msg": "badly formed hexadecimal UUID string"}
 ]
 # Generate JSON Schema
 assert deserialization_schema(Resource) == {

apischema/__init__.py

@@ -71,8 +71,8 @@ def register_default_conversions():
     """Handle standard library + internal types"""
     from . import std_types  # noqa: F401
 
-    deserializer(ValidationError.deserialize)
-    serializer(ValidationError.serialize)
+    deserializer(ValidationError.from_errors)
+    serializer(ValidationError.errors)
 
 
 register_default_conversions()

apischema/deserialization/__init__.py

@@ -126,19 +126,6 @@ def get_constraints(schema: Optional[Schema]) -> Optional[Constraints]:
     return schema.constraints if schema is not None else None
 
 
-def with_validators(
-    method: DeserializationMethod, validators: Sequence[Validator]
-) -> DeserializationMethod:
-    if not validators:
-        return method
-
-    @wraps(method)
-    def wrapper(data: Any) -> Any:
-        return validate(method(data), validators)
-
-    return wrapper
-
-
 def get_constraint_errors(
     constraints: Optional[Constraints], cls: type
 ) -> Optional[Callable[[Any], Sequence[str]]]:
@@ -201,6 +188,19 @@ def annotated(
                 )
         return factory
 
+    def _with_validators(
+        self, method: DeserializationMethod, validators: Sequence[Validator]
+    ) -> DeserializationMethod:
+        if not validators:
+            return method
+        aliaser = self.aliaser
+
+        @wraps(method)
+        def wrapper(data: Any) -> Any:
+            return validate(method(data), validators, aliaser=aliaser)
+
+        return wrapper
+
     def any(self) -> DeserializationMethodFactory:
         def factory(
             constraints: Optional[Constraints], validators: Sequence[Validator]
@@ -214,7 +214,7 @@ def method(data: Any) -> Any:
                             raise ValidationError(errors)
                 return data
 
-            return with_validators(method, validators)
+            return self._with_validators(method, validators)
 
         return DeserializationMethodFactory(factory)
 
@@ -244,7 +244,7 @@ def method(data: Any) -> Any:
                     raise ValidationError(errors, elt_errors)
                 return elts if cls is LIST_TYPE else COLLECTION_TYPES[cls](elts)
 
-            return with_validators(method, validators)
+            return self._with_validators(method, validators)
 
         return DeserializationMethodFactory(factory, list)
 
@@ -312,7 +312,7 @@ def method(data: Any) -> Any:
                     raise ValidationError(errors, item_errors)
                 return items if cls is DICT_TYPE else MAPPING_TYPES[cls](items)
 
-            return with_validators(method, validators)
+            return self._with_validators(method, validators)
 
         return DeserializationMethodFactory(factory, dict)
 
@@ -411,6 +411,7 @@ def factory(
                 flattened_fields or pattern_fields or (additional_field is not None)
             )
             constraint_errors = get_constraint_errors(constraints, dict)
+            aliaser = self.aliaser
 
             def method(data: Any) -> Any:
                 if not isinstance(data, dict):
@@ -521,7 +522,12 @@ def method(data: Any) -> Any:
                             if not v.dependencies & invalid_fields
                         ]
                         try:
-                            validate(ValidatorMock(cls, values), validators2, **init)
+                            validate(
+                                ValidatorMock(cls, values),
+                                validators2,
+                                init,
+                                aliaser=aliaser,
+                            )
                         except ValidationError as err:
                             error = merge_errors(error, err)
                         raise error
@@ -541,7 +547,7 @@ def method(data: Any) -> Any:
                 except Exception as err:
                     raise ValidationError([str(err)])
                 if validators2:
-                    validate(res, validators2, **init)
+                    validate(res, validators2, init, aliaser=aliaser)
                 return res
 
             return method
@@ -577,7 +583,7 @@ def method(data: Any) -> Any:
                     else:
                         raise bad_type(data, cls)
 
-            return with_validators(method, validators)
+            return self._with_validators(method, validators)
 
         return DeserializationMethodFactory(factory, cls)
 
@@ -627,7 +633,7 @@ def method(data: Any) -> Any:
                     raise ValidationError(errors, elt_errors)
                 return tuple(elts)
 
-            return with_validators(method, validators)
+            return self._with_validators(method, validators)
 
         return DeserializationMethodFactory(factory, list)
 

apischema/graphql/resolvers.py

@@ -26,11 +26,7 @@
 from apischema.deserialization import deserialization_method
 from apischema.objects import ObjectField
 from apischema.schemas import Schema
-from apischema.serialization import (
-    SerializationMethod,
-    SerializationMethodVisitor,
-    serialize,
-)
+from apischema.serialization import SerializationMethod, SerializationMethodVisitor
 from apischema.serialization.serialized_methods import (
     ErrorHandler,
     SerializedMethod,
@@ -292,11 +288,7 @@ def resolve(__self, __info, **kwargs):
                 values[param_name] = None
 
         if errors:
-            raise TypeError(
-                serialize(
-                    ValidationError, ValidationError(children=errors), aliaser=aliaser
-                )
-            )
+            raise ValueError(ValidationError(children=errors).errors)
         if info_parameter:
             values[info_parameter] = __info
         try:

apischema/validation/errors.py

@@ -2,12 +2,13 @@
 import re
 import sys
 import warnings
-from dataclasses import dataclass, field
+from dataclasses import dataclass, field, replace
 from functools import reduce, wraps
 from inspect import isgeneratorfunction
 from typing import (
     Any,
     Callable,
+    Collection,
     Dict,
     Generator,
     Iterable,
@@ -19,10 +20,10 @@
     Tuple,
     TypeVar,
     Union,
-    cast,
     overload,
 )
 
+from apischema.aliases import Aliaser
 from apischema.objects import AliasedStr
 from apischema.typing import get_args, is_annotated
 from apischema.utils import get_args2, get_origin2, merge_opts
@@ -36,22 +37,20 @@
 Error = Union[ErrorMsg, Tuple[Any, ErrorMsg]]
 # where  Any = Union[Field, int, str, Iterable[Union[Field, int, str,]]]
 # but Field being kind of magic not understood by type checkers, it's hidden behind Any
-ErrorKey = Union[AliasedStr, str, int]
+ErrorKey = Union[str, int]
 T = TypeVar("T")
 ValidatorResult = Generator[Error, None, T]
 
+try:
+    from apischema.typing import TypedDict
 
-@dataclass
-class LocalizedError:
-    loc: Sequence[ErrorKey]
-    err: Sequence[ErrorMsg]
+    class LocalizedError(TypedDict):
+        loc: List[ErrorKey]
+        msg: ErrorMsg
 
-    def nested(self, index=0) -> "ValidationError":
-        if index == len(self.loc):
-            return ValidationError(self.err)
-        else:
-            assert index < len(self.loc)
-            return ValidationError(children={self.loc[index]: self.nested(index + 1)})
+
+except ImportError:
+    LocalizedError = Mapping[str, Any]  # type: ignore
 
 
 @dataclass
@@ -62,20 +61,23 @@ class ValidationError(Exception):
     def __str__(self):
         return repr(self)
 
-    def flat(self) -> Iterator[Tuple[Tuple[ErrorKey, ...], Sequence[ErrorMsg]]]:
-        if self.messages:
-            yield (), self.messages
+    def _errors(self) -> Iterator[Tuple[List[ErrorKey], ErrorMsg]]:
+        for msg in self.messages:
+            yield [], msg
         for child_key in sorted(self.children):
-            for path, errors in self.children[child_key].flat():
-                yield (child_key, *path), errors
+            for path, error in self.children[child_key]._errors():
+                yield [child_key, *path], error
 
-    def serialize(self) -> Sequence[LocalizedError]:
-        return [LocalizedError(loc, err) for loc, err in self.flat()]
+    @property
+    def errors(self) -> List[LocalizedError]:
+        return [{"loc": path, "msg": error} for path, error in self._errors()]
 
     @staticmethod
-    def deserialize(errors: Sequence[LocalizedError]) -> "ValidationError":
+    def from_errors(errors: Sequence[LocalizedError]) -> "ValidationError":
         return reduce(
-            merge_errors, map(LocalizedError.nested, errors), ValidationError()
+            merge_errors,
+            [_rec_build_error(err["loc"], err["msg"]) for err in errors],
+            ValidationError(),
         )
 
 
@@ -117,8 +119,14 @@ def merge_errors(err1: ValidationError, err2: ValidationError) -> ValidationErro
     )
 
 
-def exception(err: Exception) -> str:
-    return str(err)
+def apply_aliaser(error: ValidationError, aliaser: Aliaser) -> ValidationError:
+    aliased_children = {
+        str(aliaser(key))
+        if isinstance(key, AliasedStr)
+        else key: apply_aliaser(child, aliaser)
+        for key, child in error.children.items()
+    }
+    return replace(error, children=aliased_children)
 
 
 def _rec_build_error(path: Sequence[ErrorKey], msg: ErrorMsg) -> ValidationError:
@@ -128,17 +136,6 @@ def _rec_build_error(path: Sequence[ErrorKey], msg: ErrorMsg) -> ValidationError
         return ValidationError(children={path[0]: _rec_build_error(path[1:], msg)})
 
 
-def _check_error_path(path) -> Sequence[ErrorKey]:
-    if isinstance(path, (int, str)):
-        path = (path,)
-    for i, elt in enumerate(path):
-        if not isinstance(path[i], (str, int)):
-            raise TypeError(
-                f"Bad error path, expected Field, int or str," f" found {type(i)}"
-            )
-    return cast(Sequence[ErrorKey], path)
-
-
 def build_validation_error(errors: Iterable[Error]) -> ValidationError:
     messages: List[ErrorMsg] = []
     children: Dict[ErrorKey, ValidationError] = {}
@@ -150,7 +147,9 @@ def build_validation_error(errors: Iterable[Error]) -> ValidationError:
         if not path:
             messages.append(msg)
         else:
-            key, *remain = _check_error_path(path)
+            if isinstance(path, str) or not isinstance(path, Collection):
+                path = (path,)
+            key, *remain = path
             children[key] = merge_errors(
                 children.get(key), _rec_build_error(remain, msg)
             )

apischema/validation/validators.py

@@ -10,15 +10,17 @@
     Dict,
     Iterable,
     List,
+    Mapping,
     Optional,
     Sequence,
     Type,
     TypeVar,
     overload,
 )
 
+from apischema.aliases import Aliaser
 from apischema.conversions.dataclass_models import get_model_origin, has_model_origin
-from apischema.objects import object_fields
+from apischema.objects import get_alias
 from apischema.objects.fields import FieldOrName, check_field_or_name, get_field_name
 from apischema.types import AnyType
 from apischema.typing import get_type_hints
@@ -31,6 +33,7 @@
 from apischema.validation.dependencies import find_all_dependencies
 from apischema.validation.errors import (
     ValidationError,
+    apply_aliaser,
     build_validation_error,
     merge_errors,
 )
@@ -116,22 +119,30 @@ def __set_name__(self, owner, name):
 T = TypeVar("T")
 
 
-def validate(__obj: T, __validators: Iterable[Validator] = None, **kwargs) -> T:
-    if __validators is None:
-        __validators = get_validators(type(__obj))
+def validate(
+    obj: T,
+    validators: Iterable[Validator] = None,
+    kwargs: Mapping[str, Any] = None,
+    *,
+    aliaser: Aliaser = lambda s: s,
+) -> T:
+    if validators is None:
+        validators = get_validators(type(obj))
     error: Optional[ValidationError] = None
-    __validators = iter(__validators)
-    for validator in __validators:
+    validators = iter(validators)
+    for validator in validators:
         try:
-            if kwargs and validator.params != kwargs.keys():
+            if not kwargs:
+                validator.validate(obj)
+            elif validator.params == kwargs.keys():
+                validator.validate(obj, **kwargs)
+            else:
                 if any(k not in kwargs for k in validator.params):
                     raise RuntimeError(
                         f"Missing parameters {kwargs.keys() - validator.params}"
                         f" for validator {validator.func}"
                     )
-                validator.validate(__obj, **{k: kwargs[k] for k in validator.params})
-            else:
-                validator.validate(__obj, **kwargs)
+                validator.validate(obj, **{k: kwargs[k] for k in validator.params})
         except ValidationError as e:
             err = e
         except NonTrivialDependency as exc:
@@ -143,24 +154,23 @@ def validate(__obj: T, __validators: Iterable[Validator] = None, **kwargs) -> T:
             err = ValidationError([str(e)])
         else:
             continue
+        err = apply_aliaser(err, aliaser)
         if validator.field is not None:
-            alias = object_fields(validator.owner)[
-                get_field_name(validator.field)
-            ].alias
-            err = ValidationError(children={alias: err})
+            alias = getattr(get_alias(validator.owner), get_field_name(validator.field))
+            err = ValidationError(children={aliaser(alias): err})
         error = merge_errors(error, err)
         if validator.discard:
             try:
                 discarded = set(map(get_field_name, validator.discard))
                 next_validators = (
-                    v for v in __validators if not discarded & v.dependencies
+                    v for v in validators if not discarded & v.dependencies
                 )
-                validate(__obj, next_validators, **kwargs)
+                validate(obj, next_validators, kwargs, aliaser=aliaser)
             except ValidationError as err:
                 error = merge_errors(error, err)
     if error is not None:
         raise error
-    return __obj
+    return obj
 
 
 V = TypeVar("V", bound=Callable)