allow arbitrary types in dict.pop

Author: randolf-scholz

stdlib/@tests/test_cases/builtins/check_dict.py

@@ -74,49 +74,42 @@ def test_iterable_tuple_overload(x: Iterable[tuple[int, str]]) -> dict[int, str]
 assert_type(d_any.get("key"), Union[Any, None])
 assert_type(d_any.get("key", None), Union[Any, None])
 assert_type(d_any.get("key", any_value), Any)
-assert_type(d_any.get("key", str_value), Union[Any, str])
-assert_type(d_any.get("key", int_value), Union[Any, int])
+assert_type(d_any.get("key", str_value), Any)
+assert_type(d_any.get("key", int_value), Any)
 
 assert_type(d_str["key"], str)
 assert_type(d_str.get("key"), Union[str, None])
 assert_type(d_str.get("key", None), Union[str, None])
 # Pyright has str instead of Any here
-assert_type(d_str.get("key", any_value), Union[str, Any])
+assert_type(d_str.get("key", any_value), Any)  # pyright: ignore[reportAssertTypeFailure]
 assert_type(d_str.get("key", str_value), str)
 assert_type(d_str.get("key", int_value), Union[str, int])
 
 # Now with context!
 result: str
 result = d_any["key"]
-# FIXME: https://github.com/python/mypy/issues/20576 prevents using ignore[assignment] here
-result = d_any.get("key")  # type: ignore
-# FIXME: https://github.com/python/mypy/issues/20576 prevents using ignore[assignment] here
-result = d_any.get("key", None)  # type: ignore
+result = d_any.get("key")  # type: ignore[assignment]
+result = d_any.get("key", None)  # type: ignore[assignment]
 result = d_any.get("key", any_value)
 result = d_any.get("key", str_value)
-# FIXME: https://github.com/python/mypy/issues/20576 prevents using ignore[assignment] here
-result = d_any.get("key", int_value)  # type: ignore
+result = d_any.get("key", int_value)
 
 result = d_str["key"]
-# FIXME: https://github.com/python/mypy/issues/20576 prevents using ignore[assignment] here
-result = d_str.get("key")  # type: ignore
-# FIXME: https://github.com/python/mypy/issues/20576 prevents using ignore[assignment] here
-result = d_str.get("key", None)  # type: ignore
-result = d_str.get("key", any_value)
+result = d_str.get("key")  # type: ignore[assignment]
+result = d_str.get("key", None)  # type: ignore[assignment]
+# Pyright has str | None here, see https://github.com/microsoft/pyright/discussions/9570
+result = d_str.get("key", any_value)  # pyright: ignore[reportAssignmentType]
 result = d_str.get("key", str_value)
 result = d_str.get("key", int_value)  # type: ignore[arg-type]
 
 
-def test_get_literal(d: dict[Literal["foo", "bar"], int], dynamic_key: str) -> None:
+def test_pop_literal(d: dict[Literal["foo", "bar"], int], key: str) -> None:
     # Note: annotations also allow using keys of a disjoint type (e.g., int),
     #   linters / type checkers are free to issue warnings in such cases.
     #   statically, a .get(arg) is superfluous if the intersection of the
     #   dict key type and the argument type is empty.
     #   So we only test a case with non-empty intersection here.
-
-    # check that dict wth Literal keys can get/pop a string key.
-    d.get(dynamic_key)
-    d.pop(dynamic_key)
+    d.pop(key)
 
 
 # Return values also make things weird
@@ -128,8 +121,7 @@ def test_get_literal(d: dict[Literal["foo", "bar"], int], dynamic_key: str) -> N
 
 
 def test2() -> str:
-    # FIXME: https://github.com/python/mypy/issues/20576 prevents using ignore[return-value] here
-    return d_any.get("key")  # type: ignore
+    return d_any.get("key")  # type: ignore[return-value]
 
 
 # def test3() -> str:
@@ -153,18 +145,15 @@ def test7() -> str:
 
 
 def test8() -> str:
-    # FIXME: https://github.com/python/mypy/issues/20576 prevents using ignore[return-value] here
-    return d_str.get("key")  # type: ignore
+    return d_str.get("key")  # type: ignore[return-value]
 
 
 def test9() -> str:
-    # FIXME: https://github.com/python/mypy/issues/20576 prevents using ignore[return-value] here
-    return d_str.get("key", None)  # type: ignore
+    return d_str.get("key", None)  # type: ignore[return-value]
 
 
 def test10() -> str:
-    # OK, return is Union[str, Any]
-    return d_str.get("key", any_value)
+    return d_str.get("key", any_value)  # type: ignore[no-any-return]
 
 
 def test11() -> str:

stdlib/builtins.pyi

@@ -79,7 +79,6 @@ if sys.version_info >= (3, 14):
     from _typeshed import AnnotateFunc
 
 _T = TypeVar("_T")
-_N = TypeVar("_N", default=None)
 _I = TypeVar("_I", default=int)
 _T_co = TypeVar("_T_co", covariant=True)
 _T_contra = TypeVar("_T_contra", contravariant=True)
@@ -1219,8 +1218,17 @@ class dict(MutableMapping[_KT, _VT]):
     @classmethod
     @overload
     def fromkeys(cls, iterable: Iterable[_T], value: _S, /) -> dict[_T, _S]: ...
-    def get(self, key: object, default: _N = None, /) -> _VT | _N: ...
-    def pop(self, key: object, default: _N = None, /) -> _VT | _N: ...
+    # Positional-only in dict, but not in MutableMapping
+    @overload  # type: ignore[override]
+    def get(self, key: _KT, default: None = None, /) -> _VT | None: ...
+    @overload
+    def get(self, key: _KT, default: _VT, /) -> _VT: ...
+    @overload
+    def get(self, key: _KT, default: _T, /) -> _VT | _T: ...
+    @overload
+    def pop(self, key: object, /) -> _VT: ...
+    @overload
+    def pop(self, key: object, default: _T, /) -> _VT | _T: ...
     def __len__(self) -> int: ...
     def __getitem__(self, key: _KT, /) -> _VT: ...
     def __setitem__(self, key: _KT, value: _VT, /) -> None: ...

stdlib/collections/__init__.pyi

@@ -105,15 +105,12 @@ class UserDict(MutableMapping[_KT, _VT]):
     @overload
     def __ior__(self, other: Iterable[tuple[_KT, _VT]]) -> Self: ...
     if sys.version_info >= (3, 12):
-        # UserDict allows key and default as keyword arguments
         @overload
-        def get(self, key: object, default: _T) -> _VT | _T: ...
+        def get(self, key: _KT, default: None = None) -> _VT | None: ...
         @overload
-        def get(self, key: object, default: None = None) -> _VT | None: ...
+        def get(self, key: _KT, default: _VT) -> _VT: ...
         @overload
-        def pop(self, key: object, default: _T) -> _VT | _T: ...
-        @overload  # type: ignore[override]
-        def pop(self, key: object, default: None = None) -> _VT | None: ...
+        def get(self, key: _KT, default: _T) -> _VT | _T: ...
 
 class UserList(MutableSequence[_T]):
     data: list[_T]
@@ -385,9 +382,9 @@ class OrderedDict(dict[_KT, _VT]):
     def setdefault(self, key: _KT, default: _VT) -> _VT: ...
     # Same as dict.pop, but accepts keyword arguments
     @overload
+    def pop(self, key: object) -> _VT: ...
+    @overload
     def pop(self, key: object, default: _T) -> _VT | _T: ...
-    @overload  # type: ignore[override]
-    def pop(self, key: object, default: None = None) -> _VT | None: ...
     def __eq__(self, value: object, /) -> bool: ...
     @overload
     def __or__(self, value: dict[_KT, _VT], /) -> Self: ...
@@ -474,8 +471,6 @@ class ChainMap(MutableMapping[_KT, _VT]):
     @overload
     def pop(self, key: _KT) -> _VT: ...
     @overload
-    def pop(self, key: _KT, default: _VT) -> _VT: ...
-    @overload
     def pop(self, key: _KT, default: _T) -> _VT | _T: ...
     def copy(self) -> Self: ...
     __copy__ = copy

stdlib/importlib/metadata/__init__.pyi

@@ -165,9 +165,11 @@ if sys.version_info >= (3, 10) and sys.version_info < (3, 12):
     class Deprecated(Generic[_KT, _VT]):
         def __getitem__(self, name: _KT) -> _VT: ...
         @overload
-        def get(self, key: object, default: _T) -> _VT | _T: ...
+        def get(self, name: _KT, default: None = None) -> _VT | None: ...
         @overload
-        def get(self, key: object, default: None = None) -> _VT | None: ...
+        def get(self, name: _KT, default: _VT) -> _VT: ...
+        @overload
+        def get(self, name: _KT, default: _T) -> _VT | _T: ...
         def __iter__(self) -> Iterator[_KT]: ...
         def __contains__(self, *args: object) -> bool: ...
         def keys(self) -> dict_keys[_KT, _VT]: ...

stdlib/multiprocessing/managers.pyi

@@ -88,8 +88,6 @@ if sys.version_info >= (3, 13):
         @overload
         def pop(self, key: _KT, /) -> _VT: ...
         @overload
-        def pop(self, key: _KT, default: _VT, /) -> _VT: ...
-        @overload
         def pop(self, key: _KT, default: _T, /) -> _VT | _T: ...
         def keys(self) -> list[_KT]: ...  # type: ignore[override]
         def items(self) -> list[tuple[_KT, _VT]]: ...  # type: ignore[override]

stdlib/os/__init__.pyi

@@ -719,8 +719,6 @@ class _Environ(MutableMapping[AnyStr, AnyStr], Generic[AnyStr]):
     @overload
     def pop(self, key: AnyStr) -> AnyStr: ...
     @overload
-    def pop(self, key: AnyStr, default: AnyStr) -> AnyStr: ...
-    @overload
     def pop(self, key: AnyStr, default: _T) -> AnyStr | _T: ...
     def setdefault(self, key: AnyStr, value: AnyStr) -> AnyStr: ...
     def copy(self) -> dict[AnyStr, AnyStr]: ...

stdlib/typing.pyi

@@ -792,11 +792,9 @@ class MutableMapping(Mapping[_KT, _VT]):
     def __delitem__(self, key: _KT, /) -> None: ...
     def clear(self) -> None: ...
     @overload
-    def pop(self, key: _KT, /) -> _VT: ...
+    def pop(self, key: Any, /) -> _VT: ...
     @overload
-    def pop(self, key: _KT, default: _VT, /) -> _VT: ...
-    @overload
-    def pop(self, key: _KT, default: _T, /) -> _VT | _T: ...
+    def pop(self, key: Any, default: _T, /) -> _VT | _T: ...
     def popitem(self) -> tuple[_KT, _VT]: ...
     # This overload should be allowed only if the value type is compatible with None.
     #

stdlib/weakref.pyi

@@ -114,8 +114,6 @@ class WeakValueDictionary(MutableMapping[_KT, _VT]):
     @overload
     def pop(self, key: _KT) -> _VT: ...
     @overload
-    def pop(self, key: _KT, default: _VT) -> _VT: ...
-    @overload
     def pop(self, key: _KT, default: _T) -> _VT | _T: ...
     @overload
     def update(self, other: SupportsKeysAndGetItem[_KT, _VT], /, **kwargs: _VT) -> None: ...
@@ -170,8 +168,6 @@ class WeakKeyDictionary(MutableMapping[_KT, _VT]):
     @overload
     def pop(self, key: _KT) -> _VT: ...
     @overload
-    def pop(self, key: _KT, default: _VT) -> _VT: ...
-    @overload
     def pop(self, key: _KT, default: _T) -> _VT | _T: ...
     @overload
     def update(self, dict: SupportsKeysAndGetItem[_KT, _VT], /, **kwargs: _VT) -> None: ...