bpo-36144: Add union operators to WeakKeyDictionary (#19106)
diff --git a/Doc/library/weakref.rst b/Doc/library/weakref.rst
index 8636e76..c10f436 100644
--- a/Doc/library/weakref.rst
+++ b/Doc/library/weakref.rst
@@ -171,6 +171,9 @@
performed by the program during iteration may cause items in the
dictionary to vanish "by magic" (as a side effect of garbage collection).
+ .. versionchanged:: 3.9
+ Added support for ``|`` and ``|=`` operators, specified in :pep:`584`.
+
:class:`WeakKeyDictionary` objects have an additional method that
exposes the internal references directly. The references are not guaranteed to
be "live" at the time they are used, so the result of calling the references
diff --git a/Lib/test/test_weakref.py b/Lib/test/test_weakref.py
index 63c7255..250ed40 100644
--- a/Lib/test/test_weakref.py
+++ b/Lib/test/test_weakref.py
@@ -1624,6 +1624,43 @@
self.assertEqual(len(d), 1)
self.assertEqual(list(d.keys()), [o2])
+ def test_weak_keyed_union_operators(self):
+ o1 = C()
+ o2 = C()
+ o3 = C()
+ wkd1 = weakref.WeakKeyDictionary({o1: 1, o2: 2})
+ wkd2 = weakref.WeakKeyDictionary({o3: 3, o1: 4})
+ wkd3 = wkd1.copy()
+ d1 = {o2: '5', o3: '6'}
+ pairs = [(o2, 7), (o3, 8)]
+
+ tmp1 = wkd1 | wkd2 # Between two WeakKeyDictionaries
+ self.assertEqual(dict(tmp1), dict(wkd1) | dict(wkd2))
+ self.assertIs(type(tmp1), weakref.WeakKeyDictionary)
+ wkd1 |= wkd2
+ self.assertEqual(wkd1, tmp1)
+
+ tmp2 = wkd2 | d1 # Between WeakKeyDictionary and mapping
+ self.assertEqual(dict(tmp2), dict(wkd2) | d1)
+ self.assertIs(type(tmp2), weakref.WeakKeyDictionary)
+ wkd2 |= d1
+ self.assertEqual(wkd2, tmp2)
+
+ tmp3 = wkd3.copy() # Between WeakKeyDictionary and iterable key, value
+ tmp3 |= pairs
+ self.assertEqual(dict(tmp3), dict(wkd3) | dict(pairs))
+ self.assertIs(type(tmp3), weakref.WeakKeyDictionary)
+
+ tmp4 = d1 | wkd3 # Testing .__ror__
+ self.assertEqual(dict(tmp4), d1 | dict(wkd3))
+ self.assertIs(type(tmp4), weakref.WeakKeyDictionary)
+
+ del o1
+ self.assertNotIn(4, tmp1.values())
+ self.assertNotIn(4, tmp2.values())
+ self.assertNotIn(1, tmp3.values())
+ self.assertNotIn(1, tmp4.values())
+
def test_weak_valued_delitem(self):
d = weakref.WeakValueDictionary()
o1 = Object('1')
diff --git a/Lib/weakref.py b/Lib/weakref.py
index e3c2ce2..759ad6d 100644
--- a/Lib/weakref.py
+++ b/Lib/weakref.py
@@ -488,6 +488,25 @@
if len(kwargs):
self.update(kwargs)
+ def __ior__(self, other):
+ self.update(other)
+ return self
+
+ def __or__(self, other):
+ if isinstance(other, _collections_abc.Mapping):
+ c = self.copy()
+ c.update(other)
+ return c
+ return NotImplemented
+
+ def __ror__(self, other):
+ if isinstance(other, _collections_abc.Mapping):
+ c = self.__class__()
+ c.update(other)
+ c.update(self)
+ return c
+ return NotImplemented
+
class finalize:
"""Class for finalization of weakrefable objects
diff --git a/Misc/NEWS.d/next/Library/2020-03-18-14-02-58.bpo-36144.ooyn6Z.rst b/Misc/NEWS.d/next/Library/2020-03-18-14-02-58.bpo-36144.ooyn6Z.rst
new file mode 100644
index 0000000..262653a
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2020-03-18-14-02-58.bpo-36144.ooyn6Z.rst
@@ -0,0 +1 @@
+Added :pep:`584` operators to :class:`weakref.WeakKeyDictionary`.