Imrpvoe validation error message

dlt/extract/exceptions.py

@@ -3,6 +3,7 @@
 
 from dlt.common.exceptions import DltException
 from dlt.common.utils import get_callable_name
+from dlt.extract.typing import ValidateItem, TDataItems
 
 
 class ExtractorException(DltException):
@@ -262,6 +263,8 @@ def __init__(self, cursor_path: str) -> None:
 
 
 class ValidationError(ValueError, DltException):
-    def __init__(self, original_exception: Exception) ->None:
+    def __init__(self, validator: ValidateItem, data_item: TDataItems, original_exception: Exception) ->None:
         self.original_exception = original_exception
-        super().__init__(f"Schema validation failed: {original_exception}")
+        self.validator = validator
+        self.data_item = data_item
+        super().__init__(f"Extracted data item could not be validated with {validator}. Original message: {original_exception}")

dlt/extract/validation.py

@@ -34,7 +34,10 @@ def __call__(self, item: TDataItems, meta: Any = None) -> Union[_TPydanticModel,
                 return self.list_model(items=item).items  # type: ignore[attr-defined, no-any-return]
             return self.model.parse_obj(item)
         except PydanticValidationError as e:
-            raise ValidationError(e) from e
+            raise ValidationError(self, item, e) from e
+
+    def __str__(self, *args: Any, **kwargs: Any) -> str:
+        return f"PydanticValidator(model={self.model.__qualname__})"
 
 
 def get_column_validator(columns: TTableHintTemplate[TAnySchemaColumns]) -> Optional[ValidateItem]:

tests/extract/test_validation.py

@@ -101,7 +101,7 @@ class AnotherModel(BaseModel):
     assert len(steps) == 2
 
     assert isinstance(steps[-1], ValidateItem)
-    assert steps[-1].model is AnotherModel
+    assert steps[-1].model is AnotherModel  # type: ignore[attr-defined]
 
 
 @pytest.mark.parametrize("yield_list", [True, False])
@@ -149,3 +149,4 @@ def some_data() -> t.Iterator[TDataItems]:
         list(some_data())
 
     assert isinstance(exinfo.value.__cause__, ValidationError)
+    assert str(PydanticValidator(SimpleModel)) in str(exinfo.value)