gh-101446: Change `repr` of `collections.OrderedDict` (#101661)

Lib/collections/__init__.py

@@ -267,7 +267,7 @@ class OrderedDict(dict):
         'od.__repr__() <==> repr(od)'
         if not self:
             return '%s()' % (self.__class__.__name__,)
-        return '%s(%r)' % (self.__class__.__name__, list(self.items()))
+        return '%s(%r)' % (self.__class__.__name__, dict(self.items()))
 
     def __reduce__(self):
         'Return state information for pickling'

Lib/test/test_ordered_dict.py

@@ -362,7 +362,7 @@ class OrderedDictTests:
         OrderedDict = self.OrderedDict
         od = OrderedDict([('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)])
         self.assertEqual(repr(od),
-            "OrderedDict([('c', 1), ('b', 2), ('a', 3), ('d', 4), ('e', 5), ('f', 6)])")
+            "OrderedDict({'c': 1, 'b': 2, 'a': 3, 'd': 4, 'e': 5, 'f': 6})")
         self.assertEqual(eval(repr(od)), od)
         self.assertEqual(repr(OrderedDict()), "OrderedDict()")
 
@@ -372,7 +372,7 @@ class OrderedDictTests:
         od = OrderedDict.fromkeys('abc')
         od['x'] = od
         self.assertEqual(repr(od),
-            "OrderedDict([('a', None), ('b', None), ('c', None), ('x', ...)])")
+            "OrderedDict({'a': None, 'b': None, 'c': None, 'x': ...})")
 
     def test_repr_recursive_values(self):
         OrderedDict = self.OrderedDict

Misc/NEWS.d/next/Library/2023-02-07-22-21-46.gh-issue-101446.-c0FdK.rst

@@ -0,0 +1,2 @@
+Change repr of :class:`collections.OrderedDict` to use regular dictionary
+formating instead of pairs of keys and values.

Objects/odictobject.c

@@ -1367,7 +1367,7 @@ static PyObject *
 odict_repr(PyODictObject *self)
 {
     int i;
-    PyObject *pieces = NULL, *result = NULL;
+    PyObject *result = NULL, *dcopy = NULL;
 
     if (PyODict_SIZE(self) == 0)
         return PyUnicode_FromFormat("%s()", _PyType_Name(Py_TYPE(self)));
@@ -1377,57 +1377,16 @@ odict_repr(PyODictObject *self)
         return i > 0 ? PyUnicode_FromString("...") : NULL;
     }
 
-    if (PyODict_CheckExact(self)) {
+    dcopy = PyDict_Copy((PyObject *)self);
-        Py_ssize_t count = 0;
+    if (dcopy == NULL) {
-        _ODictNode *node;
+        goto Done;
-        pieces = PyList_New(PyODict_SIZE(self));
-        if (pieces == NULL)
-            goto Done;
-
-        _odict_FOREACH(self, node) {
-            PyObject *pair;
-            PyObject *key = _odictnode_KEY(node);
-            PyObject *value = _odictnode_VALUE(node, self);
-            if (value == NULL) {
-                if (!PyErr_Occurred())
-                    PyErr_SetObject(PyExc_KeyError, key);
-                goto Done;
-            }
-            pair = PyTuple_Pack(2, key, value);
-            if (pair == NULL)
-                goto Done;
-
-            if (count < PyList_GET_SIZE(pieces))
-                PyList_SET_ITEM(pieces, count, pair);  /* steals reference */
-            else {
-                if (PyList_Append(pieces, pair) < 0) {
-                    Py_DECREF(pair);
-                    goto Done;
-                }
-                Py_DECREF(pair);
-            }
-            count++;
-        }
-        if (count < PyList_GET_SIZE(pieces)) {
-            Py_SET_SIZE(pieces, count);
-        }
-    }
-    else {
-        PyObject *items = PyObject_CallMethodNoArgs(
-                (PyObject *)self, &_Py_ID(items));
-        if (items == NULL)
-            goto Done;
-        pieces = PySequence_List(items);
-        Py_DECREF(items);
-        if (pieces == NULL)
-            goto Done;
     }
 
     result = PyUnicode_FromFormat("%s(%R)",
-                                  _PyType_Name(Py_TYPE(self)), pieces);
+                                  _PyType_Name(Py_TYPE(self)),
+                                  dcopy);
 
 Done:
-    Py_XDECREF(pieces);
     Py_ReprLeave((PyObject *)self);
     return result;
 }