From aba9763b5117494ca1ef1e420397e3845ad5b262 Mon Sep 17 00:00:00 2001
From: Raymond Hettinger <rhettinger@users.noreply.github.com>
Date: Mon, 5 Feb 2018 08:42:47 -0800
Subject: [PATCH] Refs #28814 -- Imported from collections.abc to fix Python
 3.7 deprecation warnings.

https://bugs.python.org/issue25988
---
 django/core/paginator.py            | 4 ++--
 django/db/migrations/serializer.py  | 4 ++--
 django/db/models/fields/__init__.py | 6 +++---
 django/db/models/sql/query.py       | 3 ++-
 tests/lookup/tests.py               | 4 ++--
 5 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/django/core/paginator.py b/django/core/paginator.py
index 6c9a2dac91..bc41ddb914 100644
--- a/django/core/paginator.py
+++ b/django/core/paginator.py
@@ -1,4 +1,4 @@
-import collections
+import collections.abc
 import warnings
 from math import ceil
 
@@ -127,7 +127,7 @@ class Paginator:
 QuerySetPaginator = Paginator   # For backwards-compatibility.
 
 
-class Page(collections.Sequence):
+class Page(collections.abc.Sequence):
 
     def __init__(self, object_list, number, paginator):
         self.object_list = object_list
diff --git a/django/db/migrations/serializer.py b/django/db/migrations/serializer.py
index 12fdb62cff..9b251e54cd 100644
--- a/django/db/migrations/serializer.py
+++ b/django/db/migrations/serializer.py
@@ -1,5 +1,5 @@
 import builtins
-import collections
+import collections.abc
 import datetime
 import decimal
 import enum
@@ -341,7 +341,7 @@ def serializer_factory(value):
         return FunctoolsPartialSerializer(value)
     if isinstance(value, (types.FunctionType, types.BuiltinFunctionType, types.MethodType)):
         return FunctionTypeSerializer(value)
-    if isinstance(value, collections.Iterable):
+    if isinstance(value, collections.abc.Iterable):
         return IterableSerializer(value)
     if isinstance(value, (COMPILED_REGEX_TYPE, RegexObject)):
         return RegexSerializer(value)
diff --git a/django/db/models/fields/__init__.py b/django/db/models/fields/__init__.py
index efd4c09d2f..5448a2841b 100644
--- a/django/db/models/fields/__init__.py
+++ b/django/db/models/fields/__init__.py
@@ -1,4 +1,4 @@
-import collections
+import collections.abc
 import copy
 import datetime
 import decimal
@@ -152,7 +152,7 @@ class Field(RegisterLookupMixin):
         self.unique_for_date = unique_for_date
         self.unique_for_month = unique_for_month
         self.unique_for_year = unique_for_year
-        if isinstance(choices, collections.Iterator):
+        if isinstance(choices, collections.abc.Iterator):
             choices = list(choices)
         self.choices = choices or []
         self.help_text = help_text
@@ -463,7 +463,7 @@ class Field(RegisterLookupMixin):
         for name, default in possibles.items():
             value = getattr(self, attr_overrides.get(name, name))
             # Unroll anything iterable for choices into a concrete list
-            if name == "choices" and isinstance(value, collections.Iterable):
+            if name == "choices" and isinstance(value, collections.abc.Iterable):
                 value = list(value)
             # Do correct kind of comparison
             if name in equals_comparison:
diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index b35b42f943..c8b557103f 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -6,7 +6,8 @@ themselves do not have to (and could be backed by things other than SQL
 databases). The abstraction barrier only works one way: this module has to know
 all about the internals of models in order to get the information it needs.
 """
-from collections import Counter, Iterator, Mapping, OrderedDict, namedtuple
+from collections import Counter, OrderedDict, namedtuple
+from collections.abc import Iterator, Mapping
 from itertools import chain, count, product
 from string import ascii_uppercase
 
diff --git a/tests/lookup/tests.py b/tests/lookup/tests.py
index 0161782dbe..7d7216777c 100644
--- a/tests/lookup/tests.py
+++ b/tests/lookup/tests.py
@@ -1,4 +1,4 @@
-import collections
+import collections.abc
 from datetime import datetime
 from math import ceil
 from operator import attrgetter
@@ -99,7 +99,7 @@ class LookupTests(TestCase):
     def test_iterator(self):
         # Each QuerySet gets iterator(), which is a generator that "lazily"
         # returns results using database-level iteration.
-        self.assertIsInstance(Article.objects.iterator(), collections.Iterator)
+        self.assertIsInstance(Article.objects.iterator(), collections.abc.Iterator)
 
         self.assertQuerysetEqual(
             Article.objects.iterator(),