django 5.2 compatibility

Closes #494

Author: nosnilmot

cacheops/tree.py

@@ -6,13 +6,20 @@
 from django.db.models.sql import OR
 from django.db.models.sql.datastructures import Join
 from django.db.models.sql.query import Query, ExtraWhere
-from django.db.models.sql.where import NothingNode, SubqueryConstraint
+from django.db.models.sql.where import NothingNode
 from django.db.models.lookups import Lookup, Exact, In, IsNull
 from django.db.models.expressions import BaseExpression, Exists
 
 from .conf import settings
 from .invalidation import serializable_fields
 
+# This existed prior to Django 5.2
+try:
+    from django.db.models.sql.where import SubqueryConstraint
+except ImportError:
+    class SubqueryConstraint(object):
+        pass
+
 
 def dnfs(qs):
     """

setup.py

@@ -44,6 +44,7 @@
         'Framework :: Django :: 4.1',
         'Framework :: Django :: 4.2',
         'Framework :: Django :: 5.0',
+        'Framework :: Django :: 5.2',
 
         'Environment :: Web Environment',
         'Intended Audience :: Developers',

tox.ini

@@ -4,8 +4,8 @@ envlist =
     py{38,39}-dj{32,40},
     py310-dj{32,40,41},
     py311-dj{41,42,50},
-    py312-dj{42,50},
-    py313-dj{42,50},
+    py312-dj{42,50,52},
+    py313-dj{42,50,52},
     pypy310-dj40
 
 [gh-actions]
@@ -34,6 +34,7 @@ deps =
     dj41: Django>=4.1,<4.2
     dj42: Django>=4.2.8,<5.0
     dj50: Django>=5.0,<5.1
+    dj52: Django>=5.2,<5.3
     djmain: git+https://github.com/django/django
     mysqlclient
     py{38,39,310,311,312,313}: psycopg2-binary