Mashumaro

Fix for derived data classes with fields and default_factory in ancestors

In the previous versions if a data class had been derived from another data class with a default_factory, `MissingField` would have been raised on instantiation without field value provided as it shown in the following example:

python
dataclass()
class A(DataClassJSONMixin):
foo: List[str] = field(default_factory=list)

dataclass()
class B(A):
pass

print(B.from_dict({})) MissingField: Field "foo" of type typing.List[str] is missing in __main__.B instance


Thanks to ian-sentropy who found this bug.

Features
--------
* Support Python 3.9

Fix for custom Enum serializable classes

In the version `1.12` if you inherit both `Enum` and `SerializableType` classes you will get an exception `TypeError: metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases` like in the following example:

python
class Example(IntEnum, SerializableType):
A = 1
B = 2

def _serialize(self):
return {"value": self.name}

classmethod
def _deserialize(cls, value):
return Example.__members__[value["value"]]

Fix for derived data classes without annotations

In the version `1.11` if a data class without annotations had been derived from another data class, `KeyError` would have been raised as it shown in the following example:

python
dataclass
class A:
a: int

dataclass
class B(A, DataClassDictMixin):
pass

...
KeyError: '__annotations__'

Fix constructing data class instances with inherited default values

In the previous versions there was a problem in case one data class is derived from another data class that have default values. If any ancestor had had a field with a default value, constructing an instance from a dictionary without that field would've been failed as it shown in the following example:

python
dataclass
class A:
a: int
b: int = 123

dataclass
class B(A, DataClassDictMixin):
c: int = 456

B.from_dict({'a': 111, 'c': 222}) mashumaro.exceptions.MissingField: Field "b" of type builtins.int is missing in __main__.B instance

Features
--------
* Add support for classes implementing the `os.PathLike` interface