def is_valid_type(arg, message: str, is_argument: bool = True):
"""
exposes the _type_check function from typing module that does basic validations of the type
"""
if NEW_TYPING:
return _type_check(arg, message, is_argument)
if is_classvar(arg) and not is_argument:
return arg
return _type_check(arg, message)
def _init_parametric_base(cls) -> None:
"""Initialize a direct subclass of ParametricType"""
# Direct subclasses of ParametricType must declare
# ClassVar attributes corresponding to the Generic type vars.
# For example:
# class P(ParametricType, Generic[T, V]):
# t: ClassVar[Type[T]]
# v: ClassVar[Type[V]]
params = getattr(cls, '__parameters__', None)
if not params:
raise TypeError(f'{cls} must be declared as Generic')
mod = sys.modules[cls.__module__]
annos = get_type_hints(cls, mod.__dict__)
param_map = {}
for attr, t in annos.items():
if not typing_inspect.is_classvar(t):
continue
args = typing_inspect.get_args(t)
# ClassVar constructor should have the check, but be extra safe.
assert len(args) == 1
arg = args[0]
if typing_inspect.get_origin(arg) != type:
continue
arg_args = typing_inspect.get_args(arg)
# Likewise, rely on Type checking its stuff in the constructor
assert len(arg_args) == 1
if not typing_inspect.is_typevar(arg_args[0]):
continue
if arg_args[0] in params:
param_map[arg_args[0]] = attr
for param in params:
if param not in param_map:
raise TypeError(f'{cls.__name__}: missing ClassVar for'
f' generic parameter {param}')
cls._type_param_map = param_map
def get(cls, type_or_hint, *, is_argument: bool = False) -> "TypeChecker":
# This ensures the validity of the type passed (see typing documentation for info)
type_or_hint = is_valid_type(type_or_hint, "Invalid type.",
is_argument)
if type_or_hint is Any:
return AnyTypeChecker()
if is_type(type_or_hint):
return TypeTypeChecker.make(type_or_hint, is_argument)
if is_literal_type(type_or_hint):
return LiteralTypeChecker.make(type_or_hint, is_argument)
if is_generic_type(type_or_hint):
origin = get_origin(type_or_hint)
if issubclass(origin, MappingCol):
return MappingTypeChecker.make(type_or_hint, is_argument)
if issubclass(origin, Collection):
return CollectionTypeChecker.make(type_or_hint, is_argument)
# CONSIDER: how to cater for exhaustible generators?
if issubclass(origin, Iterable):
raise NotImplementedError(
"No type-checker is setup for iterables that exhaust.")
return GenericTypeChecker.make(type_or_hint, is_argument)
if is_tuple_type(type_or_hint):
return TupleTypeChecker.make(type_or_hint, is_argument)
if is_callable_type(type_or_hint):
return CallableTypeChecker.make(type_or_hint, is_argument)
if isclass(type_or_hint):
if is_typed_dict(type_or_hint):
return TypedDictChecker.make(type_or_hint, is_argument)
return ConcreteTypeChecker.make(type_or_hint, is_argument)
if is_union_type(type_or_hint):
return UnionTypeChecker.make(type_or_hint, is_argument)
if is_typevar(type_or_hint):
bound_type = get_bound(type_or_hint)
if bound_type:
return cls.get(bound_type)
constraints = get_constraints(type_or_hint)
if constraints:
union_type_checkers = tuple(
cls.get(type_) for type_ in constraints)
return UnionTypeChecker(Union.__getitem__(constraints),
union_type_checkers)
else:
return AnyTypeChecker()
if is_new_type(type_or_hint):
super_type = getattr(type_or_hint, "__supertype__", None)
if super_type is None:
raise TypeError(
f"No supertype for NewType: {type_or_hint}. This is not allowed."
)
return cls.get(super_type)
if is_forward_ref(type_or_hint):
return ForwardTypeChecker.make(type_or_hint,
is_argument=is_argument)
if is_classvar(type_or_hint):
var_type = get_args(type_or_hint, evaluate=True)[0]
return cls.get(var_type)
raise NotImplementedError(
f"No {TypeChecker.__qualname__} is available for type or hint: '{type_or_hint}'"
)
def is_value_of_type( # noqa: C901 "too complex"
# pyre-fixme[2]: Parameter annotation cannot be `Any`.
value: Any,
# pyre-fixme[2]: Parameter annotation cannot be `Any`.
expected_type: Any,
invariant_check: bool = False,
) -> bool:
"""
This method attempts to verify a given value is of a given type. If the type is
not supported, it returns True but throws an exception in tests.
It is similar to typeguard / enforce pypi modules, but neither of those have
permissive options for types they do not support.
Supported types for now:
- List/Set/Iterable
- Dict/Mapping
- base types (str, int, etc)
- Literal
- Unions
- Tuples
- Concrete Classes
- ClassVar
Not supported:
- Callables, which will likely not be used in XHP anyways
- Generics, Type Vars (treated as Any)
- Generators
- Forward Refs -- use `typing.get_type_hints` to resolve these
- Type[...]
"""
if is_classvar(expected_type):
# `ClassVar` (no subscript) is implicitly `ClassVar[Any]`
if hasattr(expected_type, "__type__"): # py36
expected_type = expected_type.__type__ or Any
else: # py37+
classvar_args = get_args(expected_type)
expected_type = (classvar_args[0] or Any) if classvar_args else Any
if is_typevar(expected_type):
# treat this the same as Any
# TODO: evaluate bounds
return True
expected_origin_type = get_origin(expected_type) or expected_type
if expected_origin_type == Any:
return True
elif is_union_type(expected_type):
return any(
is_value_of_type(value, subtype) for subtype in expected_type.__args__
)
elif isinstance(expected_origin_type, type(Literal)):
if hasattr(expected_type, "__values__"): # py36
literal_values = expected_type.__values__
else: # py37+
literal_values = get_args(expected_type, evaluate=True)
return any(value == literal for literal in literal_values)
elif isinstance(expected_origin_type, ForwardRef):
# not much we can do here for now, lets just return :(
return True
# Handle `Tuple[A, B, C]`.
# We don't want to include Tuple subclasses, like NamedTuple, because they're
# unlikely to behave similarly.
elif expected_origin_type in [Tuple, tuple]: # py36 uses Tuple, py37+ uses tuple
if not isinstance(value, tuple):
return False
type_args = get_args(expected_type, evaluate=True)
if len(type_args) == 0:
# `Tuple` (no subscript) is implicitly `Tuple[Any, ...]`
return True
if type_args is None:
return True
if len(value) != len(type_args):
return False
# TODO: Handle `Tuple[T, ...]` like `Iterable[T]`
for subvalue, subtype in zip(value, type_args):
if not is_value_of_type(subvalue, subtype):
return False
return True
elif issubclass(expected_origin_type, Mapping):
# We're expecting *some* kind of Mapping, but we also want to make sure it's
# the correct Mapping subtype. That means we want {a: b, c: d} to match Mapping,
# MutableMapping, and Dict, but we don't want MappingProxyType({a: b, c: d}) to
# match MutableMapping or Dict.
if not issubclass(type(value), expected_origin_type):
return False
type_args = get_args(expected_type, evaluate=True)
if len(type_args) == 0:
# `Mapping` (no subscript) is implicitly `Mapping[Any, Any]`.
return True
invariant_check = issubclass(expected_origin_type, MutableMapping)
for subkey, subvalue in value.items():
if not is_value_of_type(
subkey,
type_args[0],
# key type is always invariant
invariant_check=True,
):
return False
if not is_value_of_type(
subvalue, type_args[1], invariant_check=invariant_check
):
return False
return True
# While this does technically work fine for str and bytes (they are iterables), it's
# better to use the default isinstance behavior for them.
#
# Similarly, tuple subclasses tend to have pretty different behavior, and we should
# fall back to the default check.
elif issubclass(expected_origin_type, Iterable) and not issubclass(
expected_origin_type,
(str, bytes, tuple),
):
# We know this thing is *some* kind of Iterable, but we want to
# allow subclasses. That means we want [1,2,3] to match both
# List[int] and Iterable[int], but we do NOT want that
# to match Set[int].
if not issubclass(type(value), expected_origin_type):
return False
type_args = get_args(expected_type, evaluate=True)
if len(type_args) == 0:
# `Iterable` (no subscript) is implicitly `Iterable[Any]`.
return True
# We invariant check if its a mutable sequence
invariant_check = issubclass(expected_origin_type, MutableSequence)
return all(
is_value_of_type(subvalue, type_args[0], invariant_check=invariant_check)
for subvalue in value
)
try:
if not invariant_check:
if expected_type is float:
return isinstance(value, (int, float))
else:
return isinstance(value, expected_type)
return type(value) is expected_type
except Exception as e:
raise NotImplementedError(
f"the value {value!r} was compared to type {expected_type!r} "
+ f"but support for that has not been implemented yet! Exception: {e!r}"
)
def _type_from_runtime(val, ctx):
if isinstance(val, str):
return _eval_forward_ref(val, ctx)
elif isinstance(val, tuple):
# This happens under some Python versions for types
# nested in tuples, e.g. on 3.6:
# > typing_inspect.get_args(Union[Set[int], List[str]])
# ((typing.Set, int), (typing.List, str))
origin = val[0]
if len(val) == 2:
args = (val[1], )
else:
args = val[1:]
return _value_of_origin_args(origin, args, val, ctx)
elif typing_inspect.is_literal_type(val):
args = typing_inspect.get_args(val)
if len(args) == 0:
return KnownValue(args[0])
else:
return unite_values(*[KnownValue(arg) for arg in args])
elif typing_inspect.is_union_type(val):
args = typing_inspect.get_args(val)
return unite_values(*[_type_from_runtime(arg, ctx) for arg in args])
elif typing_inspect.is_tuple_type(val):
args = typing_inspect.get_args(val)
if not args:
return TypedValue(tuple)
elif len(args) == 2 and args[1] is Ellipsis:
return GenericValue(tuple, [_type_from_runtime(args[0], ctx)])
else:
args_vals = [_type_from_runtime(arg, ctx) for arg in args]
return SequenceIncompleteValue(tuple, args_vals)
elif is_instance_of_typing_name(val, "_TypedDictMeta"):
return TypedDictValue({
key: _type_from_runtime(value, ctx)
for key, value in val.__annotations__.items()
})
elif typing_inspect.is_callable_type(val):
return TypedValue(Callable)
elif typing_inspect.is_generic_type(val):
origin = typing_inspect.get_origin(val)
args = typing_inspect.get_args(val)
return _value_of_origin_args(origin, args, val, ctx)
elif GenericAlias is not None and isinstance(val, GenericAlias):
origin = get_origin(val)
args = get_args(val)
return GenericValue(origin,
[_type_from_runtime(arg, ctx) for arg in args])
elif isinstance(val, type):
if val is type(None):
return KnownValue(None)
return TypedValue(val)
elif val is None:
return KnownValue(None)
elif is_typing_name(val, "NoReturn"):
return NO_RETURN_VALUE
elif val is typing.Any:
return UNRESOLVED_VALUE
elif hasattr(val, "__supertype__"):
if isinstance(val.__supertype__, type):
# NewType
return NewTypeValue(val)
elif typing_inspect.is_tuple_type(val.__supertype__):
# TODO figure out how to make NewTypes over tuples work
return UNRESOLVED_VALUE
else:
ctx.show_error("Invalid NewType %s" % (val, ))
return UNRESOLVED_VALUE
elif typing_inspect.is_typevar(val):
# TypeVar; not supported yet
return UNRESOLVED_VALUE
elif typing_inspect.is_classvar(val):
return UNRESOLVED_VALUE
elif is_instance_of_typing_name(
val, "_ForwardRef") or is_instance_of_typing_name(
val, "ForwardRef"):
# This has issues because the forward ref may be defined in a different file, in
# which case we don't know which names are valid in it.
with qcore.override(ctx, "suppress_undefined_name", True):
return UNRESOLVED_VALUE
elif val is Ellipsis:
# valid in Callable[..., ]
return UNRESOLVED_VALUE
elif is_instance_of_typing_name(val, "_TypeAlias"):
# typing.Pattern and Match, which are not normal generic types for some reason
return GenericValue(val.impl_type,
[_type_from_runtime(val.type_var, ctx)])
else:
origin = get_origin(val)
if origin is not None:
return TypedValue(origin)
ctx.show_error("Invalid type annotation %s" % (val, ))
return UNRESOLVED_VALUE