add fix for ki protection leaking accross local functions

Author: graingert

src/trio/_core/_ki.py

@@ -4,7 +4,7 @@
 import sys
 import types
 import weakref
-from typing import TYPE_CHECKING, Protocol, TypeVar
+from typing import TYPE_CHECKING, Any, Generic, Protocol, TypeVar
 
 import attrs
 
@@ -14,7 +14,7 @@
     import types
     from collections.abc import Callable
 
-    from typing_extensions import TypeGuard
+    from typing_extensions import Self, TypeGuard
 # In ordinary single-threaded Python code, when you hit control-C, it raises
 # an exception and automatically does all the regular unwinding stuff.
 #
@@ -77,10 +77,75 @@
 # for any Python program that's written to catch and ignore
 # KeyboardInterrupt.)
 
-_CODE_KI_PROTECTION_STATUS_WMAP: weakref.WeakKeyDictionary[
+_T = TypeVar("_T")
+
+
+class _IdRef(weakref.ref[_T]):
+    slots = "_hash"
+    _hash: int
+
+    def __new__(cls, ob: _T, callback: Callable[[Self], Any] | None = None, /) -> Self:
+        self: Self = weakref.ref.__new__(cls, ob, callback)
+        self._hash = object.__hash__(ob)
+        return self
+
+    def __eq__(self, other: object) -> bool:
+        if self is other:
+            return True
+
+        if not isinstance(other, _IdRef):
+            return NotImplemented
+
+        my_obj = None
+        other_obj: Any = None
+        try:
+            my_obj = self()
+            other_obj = other()
+            return my_obj is not None and other_obj is not None and my_obj is other_obj
+        finally:
+            del my_obj, other_obj
+
+    def __hash__(self) -> int:
+        return self._hash
+
+
+_KT = TypeVar("_KT")
+_VT = TypeVar("_VT")
+
+
+# see also: https://github.com/python/cpython/issues/88306
+class WeakKeyIdentityDictionary(Generic[_KT, _VT]):
+    def __init__(self) -> None:
+        self._data: dict[_IdRef[_KT], _VT] = {}
+
+        def remove(
+            k: _IdRef[_KT],
+            selfref: weakref.ref[
+                WeakKeyIdentityDictionary[_KT, _VT]
+            ] = weakref.ref(  # noqa: B008  # function-call-in-default-argument
+                self,
+            ),
+        ) -> None:
+            self = selfref()
+            if self is not None:
+                try:  # noqa: SIM105 # supressible-exception
+                    del self._data[k]
+                except KeyError:
+                    pass
+
+        self._remove = remove
+
+    def __getitem__(self, k: _KT) -> _VT:
+        return self._data[_IdRef(k)]
+
+    def __setitem__(self, k: _KT, v: _VT) -> None:
+        self._data[_IdRef(k, self._remove)] = v
+
+
+_CODE_KI_PROTECTION_STATUS_WMAP: WeakKeyIdentityDictionary[
     types.CodeType,
     bool,
-] = weakref.WeakKeyDictionary()
+] = WeakKeyIdentityDictionary()
 
 
 # This is to support the async_generator package necessary for aclosing on <3.10