def validate_field_value_type(value_type,
in_mapping_key=False,
allow_forward_references=False):
"""Checks that `value_type` contains only supported type annotations.
Args:
value_type: The type annotation to check.
in_mapping_key: True if `value_type` is nested in the key of a mapping.
allow_forward_references: If false, then raise an exception if a
`value_type` contains a forward reference (i.e., a string literal).
Raises:
TypeError: If `value_type` contains an unsupported type annotation.
"""
if isinstance(value_type,
str) or type_annotations.is_forward_ref(value_type):
if allow_forward_references:
return
else:
raise TypeError(f'Unresolved forward reference {value_type!r}')
if value_type in (int, float, str, bytes, bool, None, _NoneType,
dtypes.DType):
return
elif (value_type in (ops.Tensor, tensor_shape.TensorShape)
or (isinstance(value_type, type)
and issubclass(value_type, composite_tensor.CompositeTensor))):
if in_mapping_key:
raise TypeError(
f"Mapping had a key '{value_type.__name__}' with type "
f"'{type(value_type).__name__}'")
elif (type_annotations.is_generic_tuple(value_type)
or type_annotations.is_generic_union(value_type)):
type_args = type_annotations.get_generic_type_args(value_type)
if (len(type_args) == 2 and type_args[1] is Ellipsis
and type_annotations.is_generic_tuple(value_type)
): # `Tuple[X, ...]`
validate_field_value_type(type_args[0], in_mapping_key,
allow_forward_references)
else:
for arg in type_annotations.get_generic_type_args(value_type):
validate_field_value_type(arg, in_mapping_key,
allow_forward_references)
elif type_annotations.is_generic_mapping(value_type):
key_type, value_type = type_annotations.get_generic_type_args(
value_type)
validate_field_value_type(key_type, True, allow_forward_references)
validate_field_value_type(value_type, in_mapping_key,
allow_forward_references)
elif isinstance(value_type, type):
raise TypeError(f'Unsupported type annotation `{value_type.__name__}`')
else:
raise TypeError(f'Unsupported type annotation {value_type!r}')
def testIsForwardRef(self):
tp = typing.Union['B', int]
tp_args = type_annotations.get_generic_type_args(tp)
self.assertTrue(type_annotations.is_forward_ref(tp_args[0]))
self.assertFalse(type_annotations.is_forward_ref(tp_args[1]))