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[3.11] gh-91162: Support splitting of unpacked arbitrary-length tuple over TypeVar and TypeVarTuple parameters (alt) (GH-93412) (GH-93746)

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For example:

  A[T, *Ts][*tuple[int, ...]] -> A[int, *tuple[int, ...]]
  A[*Ts, T][*tuple[int, ...]] -> A[*tuple[int, ...], int]
(cherry picked from commit 3473817106)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
This commit is contained in:
Miss Islington (bot) 2022-06-14 11:15:56 -07:00 • committed by GitHub
parent 7aa4038a6e
commit 8dc5df4e21
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7 changed files with 2290 additions and 2295 deletions
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110
Lib/typing.py
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@ -1065,6 +1065,42 @@ class TypeVarTuple(_Final, _Immutable, _PickleUsingNameMixin, _root=True):
def __typing_subst__(self, arg):
raise TypeError("Substitution of bare TypeVarTuple is not supported")
def __typing_prepare_subst__(self, alias, args):
params = alias.__parameters__
typevartuple_index = params.index(self)
for param in enumerate(params[typevartuple_index + 1:]):
if isinstance(param, TypeVarTuple):
raise TypeError(f"More than one TypeVarTuple parameter in {alias}")
alen = len(args)
plen = len(params)
left = typevartuple_index
right = plen - typevartuple_index - 1
var_tuple_index = None
fillarg = None
for k, arg in enumerate(args):
if not (isinstance(arg, type) and not isinstance(arg, GenericAlias)):
subargs = getattr(arg, '__typing_unpacked_tuple_args__', None)
if subargs and len(subargs) == 2 and subargs[-1] is ...:
if var_tuple_index is not None:
raise TypeError("More than one unpacked arbitrary-length tuple argument")
var_tuple_index = k
fillarg = subargs[0]
if var_tuple_index is not None:
left = min(left, var_tuple_index)
right = min(right, alen - var_tuple_index - 1)
elif left + right > alen:
raise TypeError(f"Too few arguments for {alias};"
f" actual {alen}, expected at least {plen-1}")
return (
*args[:left],
*([fillarg]*(typevartuple_index - left)),
tuple(args[left: alen - right]),
*([fillarg]*(plen - right - left - typevartuple_index - 1)),
*args[alen - right:],
)
class ParamSpecArgs(_Final, _Immutable, _root=True):
"""The args for a ParamSpec object.
@ -1184,6 +1220,8 @@ class ParamSpec(_Final, _Immutable, _BoundVarianceMixin, _PickleUsingNameMixin,
f"ParamSpec, or Concatenate. Got {arg}")
return arg
def __typing_prepare_subst__(self, alias, args):
return _prepare_paramspec_params(alias, args)
def _is_dunder(attr):
return attr.startswith('__') and attr.endswith('__')
@ -1255,44 +1293,6 @@ class _BaseGenericAlias(_Final, _root=True):
+ [attr for attr in dir(self.__origin__) if not _is_dunder(attr)]))
def _is_unpacked_tuple(x: Any) -> bool:
# Is `x` something like `*tuple[int]` or `*tuple[int, ...]`?
if not isinstance(x, _UnpackGenericAlias):
return False
# Alright, `x` is `Unpack[something]`.
# `x` will always have `__args__`, because Unpack[] and Unpack[()]
# aren't legal.
unpacked_type = x.__args__[0]
return getattr(unpacked_type, '__origin__', None) is tuple
def _is_unpacked_arbitrary_length_tuple(x: Any) -> bool:
if not _is_unpacked_tuple(x):
return False
unpacked_tuple = x.__args__[0]
if not hasattr(unpacked_tuple, '__args__'):
# It's `Unpack[tuple]`. We can't make any assumptions about the length
# of the tuple, so it's effectively an arbitrary-length tuple.
return True
tuple_args = unpacked_tuple.__args__
if not tuple_args:
# It's `Unpack[tuple[()]]`.
return False
last_arg = tuple_args[-1]
if last_arg is Ellipsis:
# It's `Unpack[tuple[something, ...]]`, which is arbitrary-length.
return True
# If the arguments didn't end with an ellipsis, then it's not an
# arbitrary-length tuple.
return False
# Special typing constructs Union, Optional, Generic, Callable and Tuple
# use three special attributes for internal bookkeeping of generic types:
# * __parameters__ is a tuple of unique free type parameters of a generic
@ -1385,10 +1385,6 @@ class _GenericAlias(_BaseGenericAlias, _root=True):
args = (args,)
args = tuple(_type_convert(p) for p in args)
args = _unpack_args(args)
if (self._paramspec_tvars
and any(isinstance(t, ParamSpec) for t in self.__parameters__)):
args = _prepare_paramspec_params(self, args)
new_args = self._determine_new_args(args)
r = self.copy_with(new_args)
return r
@ -1410,30 +1406,16 @@ class _GenericAlias(_BaseGenericAlias, _root=True):
params = self.__parameters__
# In the example above, this would be {T3: str}
new_arg_by_param = {}
typevartuple_index = None
for i, param in enumerate(params):
if isinstance(param, TypeVarTuple):
if typevartuple_index is not None:
raise TypeError(f"More than one TypeVarTuple parameter in {self}")
typevartuple_index = i
for param in params:
prepare = getattr(param, '__typing_prepare_subst__', None)
if prepare is not None:
args = prepare(self, args)
alen = len(args)
plen = len(params)
if typevartuple_index is not None:
i = typevartuple_index
j = alen - (plen - i - 1)
if j < i:
raise TypeError(f"Too few arguments for {self};"
f" actual {alen}, expected at least {plen-1}")
new_arg_by_param.update(zip(params[:i], args[:i]))
new_arg_by_param[params[i]] = tuple(args[i: j])
new_arg_by_param.update(zip(params[i + 1:], args[j:]))
else:
if alen != plen:
raise TypeError(f"Too {'many' if alen > plen else 'few'} arguments for {self};"
f" actual {alen}, expected {plen}")
new_arg_by_param.update(zip(params, args))
if alen != plen:
raise TypeError(f"Too {'many' if alen > plen else 'few'} arguments for {self};"
f" actual {alen}, expected {plen}")
new_arg_by_param = dict(zip(params, args))
new_args = []
for old_arg in self.__args__: