bpo-27275: Change popitem() and pop() methods of collections.OrderedDict (GH-27530)

* Unify the C and Python implementations of OrderedDict.popitem().

The C implementation no longer calls ``__getitem__`` and ``__delitem__``
methods of the OrderedDict subclasses.

* Change popitem() and pop() methods of collections.OrderedDict

For consistency with dict both implementations (pure Python and C)
of these methods in OrderedDict no longer call __getitem__ and
__delitem__ methods of the OrderedDict subclasses.

Previously only the Python implementation of popitem() did not
call them.

1 files changed, 12 insertions, 4 deletions

diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py
index bae0805..d989d85 100644
--- a/Lib/collections/__init__.py
+++ b/Lib/collections/__init__.py
@@ -236,11 +236,19 @@ class OrderedDict(dict):
         is raised.
 
         '''
-        if key in self:
-            result = self[key]
-            del self[key]
+        marker = self.__marker
+        result = dict.pop(self, key, marker)
+        if result is not marker:
+            # The same as in __delitem__().
+            link = self.__map.pop(key)
+            link_prev = link.prev
+            link_next = link.next
+            link_prev.next = link_next
+            link_next.prev = link_prev
+            link.prev = None
+            link.next = None
             return result
-        if default is self.__marker:
+        if default is marker:
             raise KeyError(key)
         return default