Merge 453e009 into 3cdf4ce

pynamodb/exceptions.py

@@ -118,6 +118,15 @@ class InvalidStateError(PynamoDBException):
     msg = "Operation in invalid state"
 
 
+class AttributeDeserializationError(TypeError):
+    """
+    Raised when attribute type is invalid
+    """
+    def __init__(self, attr_name: Optional[str]):
+        msg = "Deserialization error on `{}`".format(attr_name)
+        super(AttributeDeserializationError, self).__init__(msg)
+
+
 class VerboseClientError(botocore.exceptions.ClientError):
     def __init__(self, error_response: Any, operation_name: str, verbose_properties: Optional[Any] = None):
         """ Modify the message template to include the desired verbose properties """

pynamodb/models.py

@@ -11,7 +11,7 @@
     Tuple, Union, cast
 
 from pynamodb.expressions.update import Action
-from pynamodb.exceptions import DoesNotExist, TableDoesNotExist, TableError, InvalidStateError, PutError
+from pynamodb.exceptions import DoesNotExist, TableDoesNotExist, TableError, InvalidStateError, PutError, AttributeDeserializationError
 from pynamodb.attributes import (
     Attribute, AttributeContainer, AttributeContainerMeta, MapAttribute, TTLAttribute, VersionAttribute
 )
@@ -551,7 +551,10 @@ def from_raw_data(cls: Type[_T], data: Dict[str, Any]) -> _T:
             attr_name = cls._dynamo_to_python_attr(name)
             attr = cls.get_attributes().get(attr_name, None)  # type: ignore
             if attr:
-                attributes[attr_name] = attr.deserialize(attr.get_value(value))  # type: ignore
+                try:
+                    attributes[attr_name] = attr.deserialize(attr.get_value(value))  # type: ignore
+                except TypeError as e:
+                    raise AttributeDeserializationError(attr_name=attr_name) from e
         return cls(_user_instantiated=False, **attributes)
 
     @classmethod

tests/test_model.py

@@ -14,7 +14,7 @@
 
 from .deep_eq import deep_eq
 from pynamodb.util import snake_to_camel_case
-from pynamodb.exceptions import DoesNotExist, TableError, PutError
+from pynamodb.exceptions import DoesNotExist, TableError, PutError, AttributeDeserializationError
 from pynamodb.types import RANGE
 from pynamodb.constants import (
     ITEM, STRING_SHORT, ALL, KEYS_ONLY, INCLUDE, REQUEST_ITEMS, UNPROCESSED_KEYS, CAMEL_COUNT,
@@ -3302,6 +3302,9 @@ def test_deserialized_with_ttl(self):
             m = TTLModel.from_raw_data({'user_name': {'S': 'mock'}, 'my_ttl': {'N': '1546300800'}})
         assert m.my_ttl == datetime(2019, 1, 1, tzinfo=tzutc())
 
+    def test_deserialized_with_invalid_type(self):
+        self.assertRaises(AttributeDeserializationError, TTLModel.from_raw_data, {'my_ttl': {'S': '1546300800'}})
+
     def test_multiple_version_attributes(self):
         with self.assertRaises(ValueError):
             class BadVersionedModel(Model):