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Stop inheriting Sized in collection ABCs #2658

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Merged
gvanrossum merged 4 commits into from
Nov 30, 2018
Merged

Stop inheriting Sized in collection ABCs #2658

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0e3750e
Stop inheriting Sized in collection ABCs
Nov 30, 2018
8739644
Fix tests -- MappingView has a *concrete* __len__ implementation
Nov 30, 2018
5ccb8bd
Put _Collection back in Sequence, remove unneeded __len__ from it and…
Nov 30, 2018
4f78791
Put MappingView first in ItemsView and KeysView
Nov 30, 2018
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21 changes: 17 additions & 4 deletions stdlib/2/typing.pyi
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Original file line number Diff line number Diff line change
Expand Up @@ -144,7 +144,7 @@ class Container(Protocol[_T_co]):
@abstractmethod
def __contains__(self, x: object) -> bool: ...

class Sequence(Iterable[_T_co], Container[_T_co], Sized, Reversible[_T_co], Generic[_T_co]):
class Sequence(Iterable[_T_co], Container[_T_co], Reversible[_T_co], Generic[_T_co]):
@overload
@abstractmethod
def __getitem__(self, i: int) -> _T_co: ...
Expand All @@ -157,6 +157,9 @@ class Sequence(Iterable[_T_co], Container[_T_co], Sized, Reversible[_T_co], Gene
def __contains__(self, x: object) -> bool: ...
def __iter__(self) -> Iterator[_T_co]: ...
def __reversed__(self) -> Iterator[_T_co]: ...
# Implement Sized (but don't have it as a base class).
@abstractmethod
def __len__(self) -> int: ...

class MutableSequence(Sequence[_T], Generic[_T]):
@abstractmethod
Expand Down Expand Up @@ -187,7 +190,7 @@ class MutableSequence(Sequence[_T], Generic[_T]):
def remove(self, object: _T) -> None: ...
def __iadd__(self, x: Iterable[_T]) -> MutableSequence[_T]: ...

class AbstractSet(Sized, Iterable[_T_co], Container[_T_co], Generic[_T_co]):
class AbstractSet(Iterable[_T_co], Container[_T_co], Generic[_T_co]):
@abstractmethod
def __contains__(self, x: object) -> bool: ...
# Mixin methods
Expand All @@ -201,6 +204,10 @@ class AbstractSet(Sized, Iterable[_T_co], Container[_T_co], Generic[_T_co]):
def __xor__(self, s: AbstractSet[_T]) -> AbstractSet[Union[_T_co, _T]]: ...
# TODO: argument can be any container?
def isdisjoint(self, s: AbstractSet[Any]) -> bool: ...
# Implement Sized (but don't have it as a base class).
@abstractmethod
def __len__(self) -> int: ...


class MutableSet(AbstractSet[_T], Generic[_T]):
@abstractmethod
Expand All @@ -216,7 +223,10 @@ class MutableSet(AbstractSet[_T], Generic[_T]):
def __ixor__(self, s: AbstractSet[_S]) -> MutableSet[Union[_T, _S]]: ...
def __isub__(self, s: AbstractSet[Any]) -> MutableSet[_T]: ...

class MappingView(Sized):
class MappingView:
def __len__(self) -> int: ...
# Implement Sized (but don't have it as a base class).
@abstractmethod
def __len__(self) -> int: ...

class ItemsView(AbstractSet[Tuple[_KT_co, _VT_co]], MappingView, Generic[_KT_co, _VT_co]):
Expand All @@ -238,7 +248,7 @@ class ContextManager(Protocol[_T_co]):
exc_value: Optional[BaseException],
traceback: Optional[TracebackType]) -> Optional[bool]: ...

class Mapping(Iterable[_KT], Container[_KT], Sized, Generic[_KT, _VT_co]):
class Mapping(Iterable[_KT], Container[_KT], Generic[_KT, _VT_co]):
# TODO: We wish the key type could also be covariant, but that doesn't work,
# see discussion in https: //github.com/python/typing/pull/273.
@abstractmethod
Expand All @@ -256,6 +266,9 @@ class Mapping(Iterable[_KT], Container[_KT], Sized, Generic[_KT, _VT_co]):
def itervalues(self) -> Iterator[_VT_co]: ...
def iteritems(self) -> Iterator[Tuple[_KT, _VT_co]]: ...
def __contains__(self, o: object) -> bool: ...
# Implement Sized (but don't have it as a base class).
@abstractmethod
def __len__(self) -> int: ...

class MutableMapping(Mapping[_KT, _VT], Generic[_KT, _VT]):
@abstractmethod
Expand Down
24 changes: 20 additions & 4 deletions stdlib/3/typing.pyi
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Original file line number Diff line number Diff line change
Expand Up @@ -235,13 +235,20 @@ class Container(Protocol[_T_co]):

if sys.version_info >= (3, 6):
@runtime
class Collection(Sized, Iterable[_T_co], Container[_T_co], Protocol[_T_co]): ...
class Collection(Iterable[_T_co], Container[_T_co], Protocol[_T_co]):
# Implement Sized (but don't have it as a base class).
@abstractmethod
def __len__(self) -> int: ...

_Collection = Collection
else:
@runtime
class _Collection(Sized, Iterable[_T_co], Container[_T_co], Protocol[_T_co]): ...
class _Collection(Iterable[_T_co], Container[_T_co], Protocol[_T_co]):
# Implement Sized (but don't have it as a base class).
@abstractmethod
def __len__(self) -> int: ...

class Sequence(_Collection[_T_co], Reversible[_T_co], Generic[_T_co]):
class Sequence(Iterable[_T_co], Container[_T_co], Reversible[_T_co], Generic[_T_co]):
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@JukkaL JukkaL Nov 30, 2018

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Maybe preserve _Collection here, as otherwise mypy could infer a less precise type for some type joins? Then you could leave out __len__ as it would be inherited.

@overload
@abstractmethod
def __getitem__(self, i: int) -> _T_co: ...
Expand All @@ -257,6 +264,9 @@ class Sequence(_Collection[_T_co], Reversible[_T_co], Generic[_T_co]):
def __contains__(self, x: object) -> bool: ...
def __iter__(self) -> Iterator[_T_co]: ...
def __reversed__(self) -> Iterator[_T_co]: ...
# Implement Sized (but don't have it as a base class).
@abstractmethod
def __len__(self) -> int: ...

class MutableSequence(Sequence[_T], Generic[_T]):
@abstractmethod
Expand Down Expand Up @@ -302,6 +312,9 @@ class AbstractSet(_Collection[_T_co], Generic[_T_co]):
def __xor__(self, s: AbstractSet[_T]) -> AbstractSet[Union[_T_co, _T]]: ...
# TODO: Argument can be a more general ABC?
def isdisjoint(self, s: AbstractSet[Any]) -> bool: ...
# Implement Sized (but don't have it as a base class).
@abstractmethod
def __len__(self) -> int: ...

class MutableSet(AbstractSet[_T], Generic[_T]):
@abstractmethod
Expand All @@ -317,7 +330,10 @@ class MutableSet(AbstractSet[_T], Generic[_T]):
def __ixor__(self, s: AbstractSet[_S]) -> MutableSet[Union[_T, _S]]: ...
def __isub__(self, s: AbstractSet[Any]) -> MutableSet[_T]: ...

class MappingView(Sized):
class MappingView:
def __len__(self) -> int: ...
# Implement Sized (but don't have it as a base class).
@abstractmethod
def __len__(self) -> int: ...

class ItemsView(AbstractSet[Tuple[_KT_co, _VT_co]], MappingView, Generic[_KT_co, _VT_co]):
Expand Down