Refs #26447 -- Removed the USE_ETAGS setting per deprecation timeline.

3 files changed, 1 insertions, 51 deletions

diff --git a/django/conf/global_settings.py b/django/conf/global_settings.py
index 754e6e5cdf..4d7c5854e2 100644
--- a/django/conf/global_settings.py
+++ b/django/conf/global_settings.py
@@ -21,11 +21,6 @@ DEBUG = False
 # on a live site.
 DEBUG_PROPAGATE_EXCEPTIONS = False
 
-# Whether to use the "ETag" header. This saves bandwidth but slows down performance.
-# Deprecated (RemovedInDjango21Warning) in favor of ConditionalGetMiddleware
-# which sets the ETag regardless of this setting.
-USE_ETAGS = False
-
 # People who get code error notifications.
 # In the format [('Full Name', 'email@example.com'), ('Full Name', 'anotheremail@example.com')]
 ADMINS = []
diff --git a/django/middleware/common.py b/django/middleware/common.py
index d8cfb9a8b0..7e520b7061 100644
--- a/django/middleware/common.py
+++ b/django/middleware/common.py
@@ -1,5 +1,4 @@
 import re
-import warnings
 from urllib.parse import urlparse
 
 from django.conf import settings
@@ -7,10 +6,7 @@ from django.core.exceptions import PermissionDenied
 from django.core.mail import mail_managers
 from django.http import HttpResponsePermanentRedirect
 from django.urls import is_valid_path
-from django.utils.cache import (
-    cc_delim_re, get_conditional_response, set_response_etag,
-)
-from django.utils.deprecation import MiddlewareMixin, RemovedInDjango21Warning
+from django.utils.deprecation import MiddlewareMixin
 
 
 class CommonMiddleware(MiddlewareMixin):
@@ -30,11 +26,6 @@ class CommonMiddleware(MiddlewareMixin):
 
           This behavior can be customized by subclassing CommonMiddleware and
           overriding the response_redirect_class attribute.
-
-        - ETags: If the USE_ETAGS setting is set, ETags will be calculated from
-          the entire page content and Not Modified responses will be returned
-          appropriately. USE_ETAGS is deprecated in favor of
-          ConditionalGetMiddleware.
     """
 
     response_redirect_class = HttpResponsePermanentRedirect
@@ -114,23 +105,6 @@ class CommonMiddleware(MiddlewareMixin):
             if self.should_redirect_with_slash(request):
                 return self.response_redirect_class(self.get_full_path_with_slash(request))
 
-        if settings.USE_ETAGS and self.needs_etag(response):
-            warnings.warn(
-                "The USE_ETAGS setting is deprecated in favor of "
-                "ConditionalGetMiddleware which sets the ETag regardless of "
-                "the setting. CommonMiddleware won't do ETag processing in "
-                "Django 2.1.",
-                RemovedInDjango21Warning
-            )
-            if not response.has_header('ETag'):
-                set_response_etag(response)
-
-            if response.has_header('ETag'):
-                return get_conditional_response(
-                    request,
-                    etag=response['ETag'],
-                    response=response,
-                )
         # Add the Content-Length header to non-streaming responses if not
         # already set.
         if not response.streaming and not response.has_header('Content-Length'):
@@ -138,11 +112,6 @@ class CommonMiddleware(MiddlewareMixin):
 
         return response
 
-    def needs_etag(self, response):
-        """Return True if an ETag header should be added to response."""
-        cache_control_headers = cc_delim_re.split(response.get('Cache-Control', ''))
-        return all(header.lower() != 'no-store' for header in cache_control_headers)
-
 
 class BrokenLinkEmailsMiddleware(MiddlewareMixin):
 
diff --git a/django/utils/cache.py b/django/utils/cache.py
index b1abbf0648..81fc44293e 100644
--- a/django/utils/cache.py
+++ b/django/utils/cache.py
@@ -20,12 +20,10 @@ import hashlib
 import logging
 import re
 import time
-import warnings
 
 from django.conf import settings
 from django.core.cache import caches
 from django.http import HttpResponse, HttpResponseNotModified
-from django.utils.deprecation import RemovedInDjango21Warning
 from django.utils.encoding import force_bytes, force_text, iri_to_uri
 from django.utils.http import (
     http_date, parse_etags, parse_http_date_safe, quote_etag,
@@ -248,18 +246,6 @@ def patch_response_headers(response, cache_timeout=None):
         cache_timeout = settings.CACHE_MIDDLEWARE_SECONDS
     if cache_timeout < 0:
         cache_timeout = 0  # Can't have max-age negative
-    if settings.USE_ETAGS and not response.has_header('ETag'):
-        warnings.warn(
-            "The USE_ETAGS setting is deprecated in favor of "
-            "ConditionalGetMiddleware which sets the ETag regardless of the "
-            "setting. patch_response_headers() won't do ETag processing in "
-            "Django 2.1.",
-            RemovedInDjango21Warning
-        )
-        if hasattr(response, 'render') and callable(response.render):
-            response.add_post_render_callback(set_response_etag)
-        else:
-            response = set_response_etag(response)
     if not response.has_header('Expires'):
         response['Expires'] = http_date(time.time() + cache_timeout)
     patch_cache_control(response, max_age=cache_timeout)