def test_get_default_value_for_field_without_default_value():
@dataclass
class X:
i: int
with pytest.raises(DefaultValueNotFoundError):
get_default_value_for_field(field=fields(X)[0])
def from_dict(data_class: Type[T],
data: Data,
config: Optional[Config] = None) -> T:
"""Create a data class instance from a dictionary.
:param data_class: a data class type
:param data: a dictionary of a input data
:param config: a configuration of the creation process
:return: an instance of a data class
"""
init_values: Data = {}
post_init_values: Data = {}
config = config or Config()
try:
data_class_hints = get_type_hints(data_class,
globalns=config.forward_references)
except NameError as error:
raise ForwardReferenceError(str(error))
data_class_fields = get_fields(data_class)
if config.strict:
extra_fields = set(data.keys()) - {f.name for f in data_class_fields}
if extra_fields:
raise UnexpectedDataError(keys=extra_fields)
for field in data_class_fields:
field = copy.copy(field)
field.type = data_class_hints[field.name]
try:
try:
field_data = data[field.name]
transformed_value = transform_value(
type_hooks=config.type_hooks,
cast=config.cast,
target_type=field.type,
value=field_data)
value = _build_value(type_=field.type,
data=transformed_value,
config=config)
except DaciteFieldError as error:
error.update_path(field.name)
raise
if config.check_types and not is_instance(value, field.type):
raise WrongTypeError(field_path=field.name,
field_type=field.type,
value=value)
except KeyError:
try:
value = get_default_value_for_field(field)
except DefaultValueNotFoundError:
if not field.init:
continue
raise MissingValueError(field.name)
if field.init:
init_values[field.name] = value
else:
post_init_values[field.name] = value
return create_instance(data_class=data_class,
init_values=init_values,
post_init_values=post_init_values)
def test_get_default_value_for_field_with_default_value():
@dataclass
class X:
i: int = 1
value = get_default_value_for_field(field=fields(X)[0])
assert value == 1
def test_get_default_value_for_optional_field():
@dataclass
class X:
i: Optional[int]
value = get_default_value_for_field(field=fields(X)[0])
assert value is None
def test_get_default_value_for_field_with_default_factory():
@dataclass
class X:
i: int = field(default_factory=lambda: 1)
value = get_default_value_for_field(field=fields(X)[0])
assert value == 1
def from_dict(data_class: Type[T],
data: Data,
config: Optional[Config] = None) -> T:
"""Create a data class instance from a dictionary.
:param data_class: a data class type
:param data: a dictionary of a input data
:param config: a configuration of the creation process
:return: an instance of a data class
"""
init_values: Data = {}
post_init_values: Data = {}
config = config or Config()
config.validate(data_class, data)
try:
data_class_hints = get_type_hints(data_class,
globalns=config.forward_references)
except NameError as error:
raise ForwardReferenceError(str(error))
for field in fields(data_class):
field = copy.copy(field)
field.type = data_class_hints[field.name]
try:
try:
value = _build_value(type_=field.type,
data=config.get_value(field, data),
config=config.make_inner(field))
except DaciteFieldError as error:
error.update_path(field.name)
raise
if config.check_types and not is_instance(value, field.type):
raise WrongTypeError(field_path=field.name,
field_type=field.type,
value=value)
except ValueNotFoundError:
try:
value = get_default_value_for_field(field)
except DefaultValueNotFoundError:
if not field.init:
continue
raise MissingValueError(field.name)
if field.init:
init_values[field.name] = value
else:
post_init_values[field.name] = value
return create_instance(data_class=data_class,
init_values=init_values,
post_init_values=post_init_values)
