From fcedc510e1039ab47b1c2d52f1392f298feaf81b Mon Sep 17 00:00:00 2001
From: Julius Park <Juliusgeo@gmail.com>
Date: Wed, 22 Sep 2021 12:18:19 -0700
Subject: [PATCH] PYTHON-2501 Remove iteritems from son.SON (#731)

---
 bson/son.py                 | 23 ++++++++---------------
 doc/changelog.rst           |  3 +++
 doc/migrate-to-pymongo4.rst | 15 +++++++++++++++
 pymongo/collection.py       |  2 +-
 pymongo/helpers.py          |  2 ++
 5 files changed, 29 insertions(+), 16 deletions(-)

diff --git a/bson/son.py b/bson/son.py
index a72696129..5a3210fcd 100644
--- a/bson/son.py
+++ b/bson/son.py
@@ -77,24 +77,16 @@ class SON(dict):
     def has_key(self, key):
         return key in self.__keys
 
-    # third level takes advantage of second level definitions
-    def iteritems(self):
-        for k in self:
-            yield (k, self[k])
-
     def iterkeys(self):
         return self.__iter__()
 
     # fourth level uses definitions from lower levels
     def itervalues(self):
-        for _, v in self.iteritems():
+        for _, v in self.items():
             yield v
 
     def values(self):
-        return [v for _, v in self.iteritems()]
-
-    def items(self):
-        return [(key, self[key]) for key in self]
+        return [v for _, v in self.items()]
 
     def clear(self):
         self.__keys = []
@@ -122,7 +114,7 @@ class SON(dict):
 
     def popitem(self):
         try:
-            k, v = next(self.iteritems())
+            k, v = next(iter(self.items()))
         except StopIteration:
             raise KeyError('container is empty')
         del self[k]
@@ -132,8 +124,8 @@ class SON(dict):
         # Make progressively weaker assumptions about "other"
         if other is None:
             pass
-        elif hasattr(other, 'iteritems'):  # iteritems saves memory and lookups
-            for k, v in other.iteritems():
+        elif hasattr(other, 'items'):
+            for k, v in other.items():
                 self[k] = v
         elif hasattr(other, 'keys'):
             for k in other.keys():
@@ -155,7 +147,8 @@ class SON(dict):
         regular dictionary is order-insensitive.
         """
         if isinstance(other, SON):
-            return len(self) == len(other) and self.items() == other.items()
+            return len(self) == len(other) and list(self.items()) == \
+                   list(other.items())
         return self.to_dict() == other
 
     def __ne__(self, other):
@@ -189,7 +182,7 @@ class SON(dict):
         if val_id in memo:
             return memo.get(val_id)
         memo[val_id] = out
-        for k, v in self.iteritems():
+        for k, v in self.items():
             if not isinstance(v, RE_TYPE):
                 v = copy.deepcopy(v, memo)
             out[k] = v
diff --git a/doc/changelog.rst b/doc/changelog.rst
index 6364985bb..dcc4c881c 100644
--- a/doc/changelog.rst
+++ b/doc/changelog.rst
@@ -134,6 +134,9 @@ Breaking Changes in 4.0
 - The ``hint`` option is now required when using ``min`` or ``max`` queries
   with :meth:`~pymongo.collection.Collection.find`.
 - ``name`` is now a required argument for the :class:`pymongo.driver_info.DriverInfo` class.
+- :meth:`~bson.son.SON.items` now returns a ``dict_items`` object rather
+  than a list.
+- Removed :meth:`bson.son.SON.iteritems`.
 - :class:`~pymongo.collection.Collection` and :class:`~pymongo.database.Database`
   now raises an error upon evaluating as a Boolean, please use the
   syntax ``if collection is not None:`` or ``if database is not None:`` as
diff --git a/doc/migrate-to-pymongo4.rst b/doc/migrate-to-pymongo4.rst
index 7cebec9d8..2906919b2 100644
--- a/doc/migrate-to-pymongo4.rst
+++ b/doc/migrate-to-pymongo4.rst
@@ -669,6 +669,21 @@ custom types to BSON, the :class:`~bson.codec_options.TypeCodec` and
 For more information, see the
 :doc:`custom type example <examples/custom_type>`.
 
+``SON().items()`` now returns ``dict_items`` object.
+----------------------------------------------------
+:meth:`~bson.son.SON.items` now returns a ``dict_items`` object rather than
+a list.
+
+``SON().iteritems()`` removed.
+------------------------------
+``SON.iteritems()`` now removed. Code that looks like this::
+
+    for k, v in son.iteritems():
+
+Can now be replaced by code that looks like::
+
+    for k, v in son.items():
+
 IsMaster is removed
 -------------------
 
diff --git a/pymongo/collection.py b/pymongo/collection.py
index b30bcf22f..7e8e29908 100644
--- a/pymongo/collection.py
+++ b/pymongo/collection.py
@@ -1834,7 +1834,7 @@ class Collection(common.BaseObject):
         cursor = self.list_indexes(session=session)
         info = {}
         for index in cursor:
-            index["key"] = index["key"].items()
+            index["key"] = list(index["key"].items())
             index = dict(index)
             info[index.pop("name")] = index
         return info
diff --git a/pymongo/helpers.py b/pymongo/helpers.py
index 37d6f59b7..55d53d836 100644
--- a/pymongo/helpers.py
+++ b/pymongo/helpers.py
@@ -72,6 +72,8 @@ def _index_list(key_or_list, direction=None):
     else:
         if isinstance(key_or_list, str):
             return [(key_or_list, ASCENDING)]
+        if isinstance(key_or_list, abc.ItemsView):
+            return list(key_or_list)
         elif not isinstance(key_or_list, (list, tuple)):
             raise TypeError("if no direction is specified, "
                             "key_or_list must be an instance of list")