Refs #23919 -- Stopped using django.utils.lru_cache().

21 files changed, 52 insertions, 216 deletions

diff --git a/django/apps/registry.py b/django/apps/registry.py
index 453e4d42f6..c67c5ee0ba 100644
--- a/django/apps/registry.py
+++ b/django/apps/registry.py
@@ -1,3 +1,4 @@
+import functools
 import sys
 import threading
 import warnings
@@ -5,7 +6,6 @@ from collections import Counter, OrderedDict, defaultdict
 from functools import partial
 
 from django.core.exceptions import AppRegistryNotReady, ImproperlyConfigured
-from django.utils import lru_cache
 
 from .config import AppConfig
 
@@ -156,7 +156,7 @@ class Apps(object):
             raise LookupError(message)
 
     # This method is performance-critical at least for Django's test suite.
-    @lru_cache.lru_cache(maxsize=None)
+    @functools.lru_cache(maxsize=None)
     def get_models(self, include_auto_created=False, include_swapped=False):
         """
         Returns a list of all installed models.
@@ -268,7 +268,7 @@ class Apps(object):
                 "Model '%s.%s' not registered." % (app_label, model_name))
         return model
 
-    @lru_cache.lru_cache(maxsize=None)
+    @functools.lru_cache(maxsize=None)
     def get_swappable_settings_name(self, to_string):
         """
         For a given model string (e.g. "auth.User"), return the name of the
diff --git a/django/conf/urls/i18n.py b/django/conf/urls/i18n.py
index 14f4c6971b..23e4bbcd74 100644
--- a/django/conf/urls/i18n.py
+++ b/django/conf/urls/i18n.py
@@ -1,7 +1,8 @@
+import functools
+
 from django.conf import settings
 from django.conf.urls import url
 from django.urls import LocaleRegexURLResolver, get_resolver
-from django.utils import lru_cache
 from django.views.i18n import set_language
 
 
@@ -18,7 +19,7 @@ def i18n_patterns(*urls, **kwargs):
     return [LocaleRegexURLResolver(list(urls), prefix_default_language=prefix_default_language)]
 
 
-@lru_cache.lru_cache(maxsize=None)
+@functools.lru_cache(maxsize=None)
 def is_language_prefix_patterns_used(urlconf):
     """
     Return a tuple of two booleans: (
diff --git a/django/contrib/auth/hashers.py b/django/contrib/auth/hashers.py
index 4b8b12782e..871519257a 100644
--- a/django/contrib/auth/hashers.py
+++ b/django/contrib/auth/hashers.py
@@ -1,5 +1,6 @@
 import base64
 import binascii
+import functools
 import hashlib
 import importlib
 import warnings
@@ -9,7 +10,6 @@ from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
 from django.core.signals import setting_changed
 from django.dispatch import receiver
-from django.utils import lru_cache
 from django.utils.crypto import (
     constant_time_compare, get_random_string, pbkdf2,
 )
@@ -82,7 +82,7 @@ def make_password(password, salt=None, hasher='default'):
     return hasher.encode(password, salt)
 
 
-@lru_cache.lru_cache()
+@functools.lru_cache()
 def get_hashers():
     hashers = []
     for hasher_path in settings.PASSWORD_HASHERS:
@@ -95,7 +95,7 @@ def get_hashers():
     return hashers
 
 
-@lru_cache.lru_cache()
+@functools.lru_cache()
 def get_hashers_by_algorithm():
     return {hasher.algorithm: hasher for hasher in get_hashers()}
 
diff --git a/django/contrib/auth/password_validation.py b/django/contrib/auth/password_validation.py
index 1cf32e0219..dee1ebf674 100644
--- a/django/contrib/auth/password_validation.py
+++ b/django/contrib/auth/password_validation.py
@@ -1,3 +1,4 @@
+import functools
 import gzip
 import os
 import re
@@ -7,7 +8,6 @@ from django.conf import settings
 from django.core.exceptions import (
     FieldDoesNotExist, ImproperlyConfigured, ValidationError,
 )
-from django.utils import lru_cache
 from django.utils._os import upath
 from django.utils.encoding import force_text
 from django.utils.functional import lazy
@@ -16,7 +16,7 @@ from django.utils.module_loading import import_string
 from django.utils.translation import ugettext as _, ungettext
 
 
-@lru_cache.lru_cache(maxsize=None)
+@functools.lru_cache(maxsize=None)
 def get_default_password_validators():
     return get_password_validators(settings.AUTH_PASSWORD_VALIDATORS)
 
diff --git a/django/contrib/staticfiles/finders.py b/django/contrib/staticfiles/finders.py
index c3da95ddd3..96dd705050 100644
--- a/django/contrib/staticfiles/finders.py
+++ b/django/contrib/staticfiles/finders.py
@@ -1,3 +1,4 @@
+import functools
 import os
 from collections import OrderedDict
 
@@ -8,7 +9,6 @@ from django.core.exceptions import ImproperlyConfigured
 from django.core.files.storage import (
     FileSystemStorage, Storage, default_storage,
 )
-from django.utils import lru_cache
 from django.utils._os import safe_join
 from django.utils.functional import LazyObject, empty
 from django.utils.module_loading import import_string
@@ -264,7 +264,7 @@ def get_finders():
         yield get_finder(finder_path)
 
 
-@lru_cache.lru_cache(maxsize=None)
+@functools.lru_cache(maxsize=None)
 def get_finder(import_path):
     """
     Imports the staticfiles finder class described by import_path, where
diff --git a/django/core/management/__init__.py b/django/core/management/__init__.py
index 00ee58a34b..0200f77e7d 100644
--- a/django/core/management/__init__.py
+++ b/django/core/management/__init__.py
@@ -1,3 +1,4 @@
+import functools
 import os
 import pkgutil
 import sys
@@ -12,7 +13,7 @@ from django.core.management.base import (
     BaseCommand, CommandError, CommandParser, handle_default_options,
 )
 from django.core.management.color import color_style
-from django.utils import autoreload, lru_cache
+from django.utils import autoreload
 from django.utils._os import npath, upath
 from django.utils.encoding import force_text
 
@@ -39,7 +40,7 @@ def load_command_class(app_name, name):
     return module.Command()
 
 
-@lru_cache.lru_cache(maxsize=None)
+@functools.lru_cache(maxsize=None)
 def get_commands():
     """
     Returns a dictionary mapping command names to their callback applications.
diff --git a/django/core/management/color.py b/django/core/management/color.py
index 7a32370860..76985420cb 100644
--- a/django/core/management/color.py
+++ b/django/core/management/color.py
@@ -2,10 +2,11 @@
 Sets up the terminal color scheme.
 """
 
+import functools
 import os
 import sys
 
-from django.utils import lru_cache, termcolors
+from django.utils import termcolors
 
 
 def supports_color():
@@ -57,7 +58,7 @@ def make_style(config_string=''):
     return style
 
 
-@lru_cache.lru_cache(maxsize=None)
+@functools.lru_cache(maxsize=None)
 def no_style():
     """
     Returns a Style object with no color scheme.
diff --git a/django/core/management/commands/loaddata.py b/django/core/management/commands/loaddata.py
index 9f71400862..9edd642b43 100644
--- a/django/core/management/commands/loaddata.py
+++ b/django/core/management/commands/loaddata.py
@@ -1,3 +1,4 @@
+import functools
 import glob
 import gzip
 import os
@@ -16,7 +17,6 @@ from django.db import (
     DEFAULT_DB_ALIAS, DatabaseError, IntegrityError, connections, router,
     transaction,
 )
-from django.utils import lru_cache
 from django.utils._os import upath
 from django.utils.encoding import force_text
 from django.utils.functional import cached_property
@@ -202,7 +202,7 @@ class Command(BaseCommand):
                     RuntimeWarning
                 )
 
-    @lru_cache.lru_cache(maxsize=None)
+    @functools.lru_cache(maxsize=None)
     def find_fixtures(self, fixture_label):
         """
         Finds fixture files for a given label.
diff --git a/django/db/models/fields/related.py b/django/db/models/fields/related.py
index 65d0da41e1..b5dd0a2d14 100644
--- a/django/db/models/fields/related.py
+++ b/django/db/models/fields/related.py
@@ -1,3 +1,4 @@
+import functools
 import inspect
 from functools import partial
 
@@ -13,7 +14,6 @@ from django.db.models.query_utils import PathInfo
 from django.db.models.utils import make_model_tuple
 from django.utils.encoding import force_text
 from django.utils.functional import cached_property, curry
-from django.utils.lru_cache import lru_cache
 from django.utils.translation import ugettext_lazy as _
 
 from . import Field
@@ -710,7 +710,7 @@ class ForeignObject(RelatedField):
         return pathinfos
 
     @classmethod
-    @lru_cache(maxsize=None)
+    @functools.lru_cache(maxsize=None)
     def get_lookups(cls):
         bases = inspect.getmro(cls)
         bases = bases[:bases.index(ForeignObject) + 1]
diff --git a/django/db/models/query_utils.py b/django/db/models/query_utils.py
index 112c9586d0..03d133e724 100644
--- a/django/db/models/query_utils.py
+++ b/django/db/models/query_utils.py
@@ -5,12 +5,12 @@ Factored out from django.db.models.query to avoid making the main module very
 large and/or so that they can be used by other modules without getting into
 circular import difficulties.
 """
+import functools
 import inspect
 from collections import namedtuple
 
 from django.db.models.constants import LOOKUP_SEP
 from django.utils import tree
-from django.utils.lru_cache import lru_cache
 
 # PathInfo is used when converting lookups (fk__somecol). The contents
 # describe the relation in Model terms (model Options and Fields for both
@@ -137,7 +137,7 @@ class RegisterLookupMixin(object):
         return cls.get_lookups().get(lookup_name, None)
 
     @classmethod
-    @lru_cache(maxsize=None)
+    @functools.lru_cache(maxsize=None)
     def get_lookups(cls):
         class_lookups = [parent.__dict__.get('class_lookups', {}) for parent in inspect.getmro(cls)]
         return cls.merge_dicts(class_lookups)
diff --git a/django/forms/renderers.py b/django/forms/renderers.py
index d0b3c3e2db..2c31d7adc5 100644
--- a/django/forms/renderers.py
+++ b/django/forms/renderers.py
@@ -1,9 +1,9 @@
+import functools
 import os
 
 from django.conf import settings
 from django.template.backends.django import DjangoTemplates
 from django.template.loader import get_template
-from django.utils import lru_cache
 from django.utils._os import upath
 from django.utils.functional import cached_property
 from django.utils.module_loading import import_string
@@ -17,7 +17,7 @@ except ImportError:
 ROOT = upath(os.path.dirname(__file__))
 
 
-@lru_cache.lru_cache()
+@functools.lru_cache()
 def get_default_renderer():
     renderer_class = import_string(settings.FORM_RENDERER)
     return renderer_class()
diff --git a/django/template/engine.py b/django/template/engine.py
index 6d73569e02..d334926c45 100644
--- a/django/template/engine.py
+++ b/django/template/engine.py
@@ -1,5 +1,6 @@
+import functools
+
 from django.core.exceptions import ImproperlyConfigured
-from django.utils import lru_cache
 from django.utils.functional import cached_property
 from django.utils.module_loading import import_string
 
@@ -52,7 +53,7 @@ class Engine(object):
         self.template_builtins = self.get_template_builtins(self.builtins)
 
     @staticmethod
-    @lru_cache.lru_cache()
+    @functools.lru_cache()
     def get_default():
         """
         When only one DjangoTemplates backend is configured, returns it.
diff --git a/django/template/utils.py b/django/template/utils.py
index 3c7b3c98ac..6ff2499dcb 100644
--- a/django/template/utils.py
+++ b/django/template/utils.py
@@ -1,10 +1,10 @@
+import functools
 import os
 from collections import Counter, OrderedDict
 
 from django.apps import apps
 from django.conf import settings
 from django.core.exceptions import ImproperlyConfigured
-from django.utils import lru_cache
 from django.utils._os import upath
 from django.utils.functional import cached_property
 from django.utils.module_loading import import_string
@@ -89,7 +89,7 @@ class EngineHandler(object):
         return [self[alias] for alias in self]
 
 
-@lru_cache.lru_cache()
+@functools.lru_cache()
 def get_app_template_dirs(dirname):
     """
     Return an iterable of paths of directories to load app templates from.
diff --git a/django/urls/resolvers.py b/django/urls/resolvers.py
index cf2fe0ecec..7e344896af 100644
--- a/django/urls/resolvers.py
+++ b/django/urls/resolvers.py
@@ -14,7 +14,6 @@ from django.conf import settings
 from django.core.checks import Warning
 from django.core.checks.urls import check_resolver
 from django.core.exceptions import ImproperlyConfigured
-from django.utils import lru_cache
 from django.utils.datastructures import MultiValueDict
 from django.utils.encoding import force_str, force_text
 from django.utils.functional import cached_property
@@ -60,7 +59,7 @@ class ResolverMatch(object):
         )
 
 
-@lru_cache.lru_cache(maxsize=None)
+@functools.lru_cache(maxsize=None)
 def get_resolver(urlconf=None):
     if urlconf is None:
         from django.conf import settings
@@ -68,7 +67,7 @@ def get_resolver(urlconf=None):
     return RegexURLResolver(r'^/', urlconf)
 
 
-@lru_cache.lru_cache(maxsize=None)
+@functools.lru_cache(maxsize=None)
 def get_ns_resolver(ns_pattern, resolver):
     # Build a namespaced resolver for the given parent URLconf pattern.
     # This makes it possible to have captured parameters in the parent
diff --git a/django/urls/utils.py b/django/urls/utils.py
index 3cf5439e77..e59ab9fdbd 100644
--- a/django/urls/utils.py
+++ b/django/urls/utils.py
@@ -1,11 +1,11 @@
+import functools
 from importlib import import_module
 
 from django.core.exceptions import ViewDoesNotExist
-from django.utils import lru_cache
 from django.utils.module_loading import module_has_submodule
 
 
-@lru_cache.lru_cache(maxsize=None)
+@functools.lru_cache(maxsize=None)
 def get_callable(lookup_view):
     """
     Return a callable corresponding to lookup_view.
diff --git a/django/utils/lru_cache.py b/django/utils/lru_cache.py
index 543296e648..f5187ded56 100644
--- a/django/utils/lru_cache.py
+++ b/django/utils/lru_cache.py
@@ -1,172 +1,5 @@
-try:
-    from functools import lru_cache
+from functools import lru_cache  # noqa
 
-except ImportError:
-    # backport of Python's 3.3 lru_cache, written by Raymond Hettinger and
-    # licensed under MIT license, from:
-    # <http://code.activestate.com/recipes/578078-py26-and-py30-backport-of-python-33s-lru-cache/>
-    # Should be removed when Django only supports Python 3.2 and above.
-
-    from collections import namedtuple
-    from functools import update_wrapper
-    from threading import RLock
-
-    _CacheInfo = namedtuple("CacheInfo", ["hits", "misses", "maxsize", "currsize"])
-
-    class _HashedSeq(list):
-        __slots__ = 'hashvalue'
-
-        def __init__(self, tup, hash=hash):
-            self[:] = tup
-            self.hashvalue = hash(tup)
-
-        def __hash__(self):
-            return self.hashvalue
-
-    def _make_key(args, kwds, typed,
-                 kwd_mark = (object(),),
-                 fasttypes = {int, str, frozenset, type(None)},
-                 sorted=sorted, tuple=tuple, type=type, len=len):
-        'Make a cache key from optionally typed positional and keyword arguments'
-        key = args
-        if kwds:
-            sorted_items = sorted(kwds.items())
-            key += kwd_mark
-            for item in sorted_items:
-                key += item
-        if typed:
-            key += tuple(type(v) for v in args)
-            if kwds:
-                key += tuple(type(v) for k, v in sorted_items)
-        elif len(key) == 1 and type(key[0]) in fasttypes:
-            return key[0]
-        return _HashedSeq(key)
-
-    def lru_cache(maxsize=100, typed=False):
-        """Least-recently-used cache decorator.
-
-        If *maxsize* is set to None, the LRU features are disabled and the cache
-        can grow without bound.
-
-        If *typed* is True, arguments of different types will be cached separately.
-        For example, f(3.0) and f(3) will be treated as distinct calls with
-        distinct results.
-
-        Arguments to the cached function must be hashable.
-
-        View the cache statistics named tuple (hits, misses, maxsize, currsize) with
-        f.cache_info().  Clear the cache and statistics with f.cache_clear().
-        Access the underlying function with f.__wrapped__.
-
-        See:  https://en.wikipedia.org/wiki/Cache_algorithms#Least_Recently_Used
-        """
-
-        # Users should only access the lru_cache through its public API:
-        #       cache_info, cache_clear, and f.__wrapped__
-        # The internals of the lru_cache are encapsulated for thread safety and
-        # to allow the implementation to change (including a possible C version).
-
-        def decorating_function(user_function):
-
-            cache = dict()
-            stats = [0, 0]                  # make statistics updateable non-locally
-            HITS, MISSES = 0, 1             # names for the stats fields
-            make_key = _make_key
-            cache_get = cache.get           # bound method to lookup key or return None
-            _len = len                      # localize the global len() function
-            lock = RLock()                  # because linkedlist updates aren't threadsafe
-            root = []                       # root of the circular doubly linked list
-            root[:] = [root, root, None, None]      # initialize by pointing to self
-            nonlocal_root = [root]                  # make updateable non-locally
-            PREV, NEXT, KEY, RESULT = 0, 1, 2, 3    # names for the link fields
-
-            if maxsize == 0:
-
-                def wrapper(*args, **kwds):
-                    # no caching, just do a statistics update after a successful call
-                    result = user_function(*args, **kwds)
-                    stats[MISSES] += 1
-                    return result
-
-            elif maxsize is None:
-
-                def wrapper(*args, **kwds):
-                    # simple caching without ordering or size limit
-                    key = make_key(args, kwds, typed)
-                    result = cache_get(key, root)   # root used here as a unique not-found sentinel
-                    if result is not root:
-                        stats[HITS] += 1
-                        return result
-                    result = user_function(*args, **kwds)
-                    cache[key] = result
-                    stats[MISSES] += 1
-                    return result
-
-            else:
-
-                def wrapper(*args, **kwds):
-                    # size limited caching that tracks accesses by recency
-                    key = make_key(args, kwds, typed) if kwds or typed else args
-                    with lock:
-                        link = cache_get(key)
-                        if link is not None:
-                            # record recent use of the key by moving it to the front of the list
-                            root, = nonlocal_root
-                            link_prev, link_next, key, result = link
-                            link_prev[NEXT] = link_next
-                            link_next[PREV] = link_prev
-                            last = root[PREV]
-                            last[NEXT] = root[PREV] = link
-                            link[PREV] = last
-                            link[NEXT] = root
-                            stats[HITS] += 1
-                            return result
-                    result = user_function(*args, **kwds)
-                    with lock:
-                        root, = nonlocal_root
-                        if key in cache:
-                            # getting here means that this same key was added to the
-                            # cache while the lock was released.  since the link
-                            # update is already done, we need only return the
-                            # computed result and update the count of misses.
-                            pass
-                        elif _len(cache) >= maxsize:
-                            # use the old root to store the new key and result
-                            oldroot = root
-                            oldroot[KEY] = key
-                            oldroot[RESULT] = result
-                            # empty the oldest link and make it the new root
-                            root = nonlocal_root[0] = oldroot[NEXT]
-                            oldkey = root[KEY]
-                            oldvalue = root[RESULT]
-                            root[KEY] = root[RESULT] = None
-                            # now update the cache dictionary for the new links
-                            del cache[oldkey]
-                            cache[key] = oldroot
-                        else:
-                            # put result in a new link at the front of the list
-                            last = root[PREV]
-                            link = [last, root, key, result]
-                            last[NEXT] = root[PREV] = cache[key] = link
-                        stats[MISSES] += 1
-                    return result
-
-            def cache_info():
-                """Report cache statistics"""
-                with lock:
-                    return _CacheInfo(stats[HITS], stats[MISSES], maxsize, len(cache))
-
-            def cache_clear():
-                """Clear the cache and cache statistics"""
-                with lock:
-                    cache.clear()
-                    root = nonlocal_root[0]
-                    root[:] = [root, root, None, None]
-                    stats[:] = [0, 0]
-
-            wrapper.__wrapped__ = user_function
-            wrapper.cache_info = cache_info
-            wrapper.cache_clear = cache_clear
-            return update_wrapper(wrapper, user_function)
-
-        return decorating_function
+# Deprecate or remove this module when no supported version of Django still
+# supports Python 2. Until then, keep it to allow pluggable apps to support
+# Python 2 and Python 3 without raising a deprecation warning.
diff --git a/django/utils/timezone.py b/django/utils/timezone.py
index 992e80086a..66bfa00030 100644
--- a/django/utils/timezone.py
+++ b/django/utils/timezone.py
@@ -2,13 +2,13 @@
 Timezone-related classes and functions.
 """
 
+import functools
 from datetime import datetime, timedelta, tzinfo
 from threading import local
 
 import pytz
 
 from django.conf import settings
-from django.utils import lru_cache
 from django.utils.decorators import ContextDecorator
 
 __all__ = [
@@ -69,7 +69,7 @@ def get_fixed_timezone(offset):
 
 # In order to avoid accessing settings at compile time,
 # wrap the logic in a function and cache the result.
-@lru_cache.lru_cache()
+@functools.lru_cache()
 def get_default_timezone():
     """
     Returns the default time zone as a tzinfo instance.
diff --git a/django/utils/translation/trans_real.py b/django/utils/translation/trans_real.py
index aca57ded0e..99acda9aab 100644
--- a/django/utils/translation/trans_real.py
+++ b/django/utils/translation/trans_real.py
@@ -1,4 +1,5 @@
 """Translation helper functions."""
+import functools
 import gettext as gettext_module
 import os
 import re
@@ -13,7 +14,6 @@ from django.conf.locale import LANG_INFO
 from django.core.exceptions import AppRegistryNotReady
 from django.core.signals import setting_changed
 from django.dispatch import receiver
-from django.utils import lru_cache
 from django.utils._os import upath
 from django.utils.encoding import force_text
 from django.utils.safestring import SafeData, mark_safe
@@ -403,7 +403,7 @@ def all_locale_paths():
     return [globalpath] + list(settings.LOCALE_PATHS)
 
 
-@lru_cache.lru_cache(maxsize=1000)
+@functools.lru_cache(maxsize=1000)
 def check_for_language(lang_code):
     """
     Checks whether there is a global language file for the given language
@@ -423,7 +423,7 @@ def check_for_language(lang_code):
     return False
 
 
-@lru_cache.lru_cache()
+@functools.lru_cache()
 def get_languages():
     """
     Cache of settings.LANGUAGES in an OrderedDict for easy lookups by key.
@@ -431,7 +431,7 @@ def get_languages():
     return OrderedDict(settings.LANGUAGES)
 
 
-@lru_cache.lru_cache(maxsize=1000)
+@functools.lru_cache(maxsize=1000)
 def get_supported_language_variant(lang_code, strict=False):
     """
     Returns the language-code that's listed in supported languages, possibly
diff --git a/django/utils/version.py b/django/utils/version.py
index dcf0c21866..e9666f906e 100644
--- a/django/utils/version.py
+++ b/django/utils/version.py
@@ -1,9 +1,8 @@
 import datetime
+import functools
 import os
 import subprocess
 
-from django.utils.lru_cache import lru_cache
-
 
 def get_version(version=None):
     "Returns a PEP 440-compliant version number from VERSION."
@@ -57,7 +56,7 @@ def get_docs_version(version=None):
         return '%d.%d' % version[:2]
 
 
-@lru_cache()
+@functools.lru_cache()
 def get_git_changeset():
     """Returns a numeric identifier of the latest git changeset.
 
diff --git a/django/views/debug.py b/django/views/debug.py
index de8c4319bf..b457969427 100644
--- a/django/views/debug.py
+++ b/django/views/debug.py
@@ -1,3 +1,4 @@
+import functools
 import re
 import sys
 import types
@@ -7,7 +8,7 @@ from django.http import HttpResponse, HttpResponseNotFound
 from django.template import Context, Engine, TemplateDoesNotExist
 from django.template.defaultfilters import force_escape, pprint
 from django.urls import Resolver404, resolve
-from django.utils import lru_cache, timezone
+from django.utils import timezone
 from django.utils.datastructures import MultiValueDict
 from django.utils.encoding import force_bytes, force_text
 from django.utils.module_loading import import_string
@@ -83,7 +84,7 @@ def technical_500_response(request, exc_type, exc_value, tb, status_code=500):
         return HttpResponse(html, status=status_code, content_type='text/html')
 
 
-@lru_cache.lru_cache()
+@functools.lru_cache()
 def get_default_exception_reporter_filter():
     # Instantiate the default filter for the first time and cache it.
     return import_string(settings.DEFAULT_EXCEPTION_REPORTER_FILTER)()
diff --git a/setup.cfg b/setup.cfg
index c1ff45c56a..726bddb3af 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -3,7 +3,7 @@ doc_files = docs extras AUTHORS INSTALL LICENSE README.rst
 install-script = scripts/rpm-install.sh
 
 [flake8]
-exclude = build,.git,.tox,./django/utils/lru_cache.py,./django/utils/six.py,./django/conf/app_template/*,./tests/.env,./xmlrunner
+exclude = build,.git,.tox,./django/utils/six.py,./django/conf/app_template/*,./tests/.env,./xmlrunner
 ignore = W601
 max-line-length = 119