Fixed #28933 -- Improved the efficiency of ModelAdmin.date_hierarchy queries.

django/contrib/admin/views/main.py

@@ -1,5 +1,7 @@
 from collections import OrderedDict
+from datetime import datetime, timedelta
 
+from django.conf import settings
 from django.contrib.admin import FieldListFilter
 from django.contrib.admin.exceptions import (
     DisallowedModelAdminLookup, DisallowedModelAdminToField,
@@ -18,6 +20,7 @@ from django.db import models
 from django.db.models.expressions import F, OrderBy
 from django.urls import reverse
 from django.utils.http import urlencode
+from django.utils.timezone import make_aware
 from django.utils.translation import gettext
 
 # Changelist settings
@@ -136,6 +139,36 @@ class ChangeList:
             if spec and spec.has_output():
                 filter_specs.append(spec)
 
+        if self.date_hierarchy:
+            # Create bounded lookup parameters so that the query is more
+            # efficient.
+            year = lookup_params.pop('%s__year' % self.date_hierarchy, None)
+            if year is not None:
+                month = lookup_params.pop('%s__month' % self.date_hierarchy, None)
+                day = lookup_params.pop('%s__day' % self.date_hierarchy, None)
+                try:
+                    from_date = datetime(
+                        int(year),
+                        int(month if month is not None else 1),
+                        int(day if day is not None else 1),
+                    )
+                except ValueError as e:
+                    raise IncorrectLookupParameters(e) from e
+                if settings.USE_TZ:
+                    from_date = make_aware(from_date)
+                if day:
+                    to_date = from_date + timedelta(days=1)
+                elif month:
+                    # In this branch, from_date will always be the first of a
+                    # month, so advancing 32 days gives the next month.
+                    to_date = (from_date + timedelta(days=32)).replace(day=1)
+                else:
+                    to_date = from_date.replace(year=from_date.year + 1)
+                lookup_params.update({
+                    '%s__gte' % self.date_hierarchy: from_date,
+                    '%s__lt' % self.date_hierarchy: to_date,
+                })
+
         # At this point, all the parameters used by the various ListFilters
         # have been removed from lookup_params, which now only contains other
         # parameters passed via the query string. We now loop through the

tests/admin_changelist/admin.py

@@ -16,6 +16,7 @@ class CustomPaginator(Paginator):
 
 
 class EventAdmin(admin.ModelAdmin):
+    date_hierarchy = 'date'
     list_display = ['event_date_func']
 
     def event_date_func(self, event):

tests/admin_changelist/test_date_hierarchy.py

@@ -0,0 +1,55 @@
+from datetime import datetime
+
+from django.contrib.admin.options import IncorrectLookupParameters
+from django.test import RequestFactory, TestCase
+from django.utils.timezone import make_aware
+
+from .admin import EventAdmin, site as custom_site
+from .models import Event
+
+
+class DateHierarchyTests(TestCase):
+    factory = RequestFactory()
+
+    def assertDateParams(self, query, expected_from_date, expected_to_date):
+        query = {'date__%s' % field: val for field, val in query.items()}
+        request = self.factory.get('/', query)
+        changelist = EventAdmin(Event, custom_site).get_changelist_instance(request)
+        _, _, lookup_params, _ = changelist.get_filters(request)
+        self.assertEqual(lookup_params['date__gte'], expected_from_date)
+        self.assertEqual(lookup_params['date__lt'], expected_to_date)
+
+    def test_bounded_params(self):
+        tests = (
+            ({'year': 2017}, datetime(2017, 1, 1), datetime(2018, 1, 1)),
+            ({'year': 2017, 'month': 2}, datetime(2017, 2, 1), datetime(2017, 3, 1)),
+            ({'year': 2017, 'month': 12}, datetime(2017, 12, 1), datetime(2018, 1, 1)),
+            ({'year': 2017, 'month': 12, 'day': 15}, datetime(2017, 12, 15), datetime(2017, 12, 16)),
+            ({'year': 2017, 'month': 12, 'day': 31}, datetime(2017, 12, 31), datetime(2018, 1, 1)),
+            ({'year': 2017, 'month': 2, 'day': 28}, datetime(2017, 2, 28), datetime(2017, 3, 1)),
+        )
+        for query, expected_from_date, expected_to_date in tests:
+            with self.subTest(query=query):
+                self.assertDateParams(query, expected_from_date, expected_to_date)
+
+    def test_bounded_params_with_time_zone(self):
+        with self.settings(USE_TZ=True, TIME_ZONE='Asia/Jerusalem'):
+            self.assertDateParams(
+                {'year': 2017, 'month': 2, 'day': 28},
+                make_aware(datetime(2017, 2, 28)),
+                make_aware(datetime(2017, 3, 1)),
+            )
+
+    def test_invalid_params(self):
+        tests = (
+            {'year': 'x'},
+            {'year': 2017, 'month': 'x'},
+            {'year': 2017, 'month': 12, 'day': 'x'},
+            {'year': 2017, 'month': 13},
+            {'year': 2017, 'month': 12, 'day': 32},
+            {'year': 2017, 'month': 0},
+            {'year': 2017, 'month': 12, 'day': 0},
+        )
+        for invalid_query in tests:
+            with self.subTest(query=invalid_query), self.assertRaises(IncorrectLookupParameters):
+                self.assertDateParams(invalid_query, None, None)