Support dict(foo.split() for foo in bar) with bytes (#10072)

Author: Akuli

stdlib/builtins.pyi

@@ -1032,10 +1032,12 @@ class dict(MutableMapping[_KT, _VT], Generic[_KT, _VT]):
     def __init__(self, __iterable: Iterable[tuple[_KT, _VT]]) -> None: ...
     @overload
     def __init__(self: dict[str, _VT], __iterable: Iterable[tuple[str, _VT]], **kwargs: _VT) -> None: ...
-    # Next overload is for dict(string.split(sep) for string in iterable)
+    # Next two overloads are for dict(string.split(sep) for string in iterable)
     # Cannot be Iterable[Sequence[_T]] or otherwise dict(["foo", "bar", "baz"]) is not an error
     @overload
     def __init__(self: dict[str, str], __iterable: Iterable[list[str]]) -> None: ...
+    @overload
+    def __init__(self: dict[bytes, bytes], __iterable: Iterable[list[bytes]]) -> None: ...
     def __new__(cls, *args: Any, **kwargs: Any) -> Self: ...
     def copy(self) -> dict[_KT, _VT]: ...
     def keys(self) -> dict_keys[_KT, _VT]: ...

stdlib/collections/__init__.pyi

@@ -62,6 +62,8 @@ class UserDict(MutableMapping[_KT, _VT], Generic[_KT, _VT]):
     def __init__(self: UserDict[str, _VT], __iterable: Iterable[tuple[str, _VT]], **kwargs: _VT) -> None: ...
     @overload
     def __init__(self: UserDict[str, str], __iterable: Iterable[list[str]]) -> None: ...
+    @overload
+    def __init__(self: UserDict[bytes, bytes], __iterable: Iterable[list[bytes]]) -> None: ...
     def __len__(self) -> int: ...
     def __getitem__(self, key: _KT) -> _VT: ...
     def __setitem__(self, key: _KT, item: _VT) -> None: ...

stdlib/multiprocessing/managers.pyi

@@ -197,6 +197,8 @@ class SyncManager(BaseManager):
     @overload
     def dict(self, __iterable: Iterable[list[str]]) -> DictProxy[str, str]: ...
     @overload
+    def dict(self, __iterable: Iterable[list[bytes]]) -> DictProxy[bytes, bytes]: ...
+    @overload
     def list(self, __sequence: Sequence[_T]) -> ListProxy[_T]: ...
     @overload
     def list(self) -> ListProxy[Any]: ...

test_cases/stdlib/builtins/check_dict.py

@@ -50,5 +50,9 @@ def test_iterable_tuple_overload(x: Iterable[tuple[int, str]]) -> dict[int, str]
 assert_type(dict(i2, arg=1), Dict[str, int])
 
 i3: Iterable[str] = ["a.b"]
+i4: Iterable[bytes] = [b"a.b"]
 assert_type(dict(string.split(".") for string in i3), Dict[str, str])
+assert_type(dict(string.split(b".") for string in i4), Dict[bytes, bytes])
+
 dict(["foo", "bar", "baz"])  # type: ignore
+dict([b"foo", b"bar", b"baz"])  # type: ignore