Fixed #24397 -- Sped up rendering multiple model states.

Set apps.ready to False when rendering multiple models. This prevents
that the cache on Model._meta is expired on all models after each time a
single model is rendered. Prevented that Apps.clear_cache() refills the
cache on Apps.get_models(), so that the wrong value cannot be cached
when cloning a StateApps.

1 files changed, 5 insertions, 2 deletions

diff --git a/django/apps/registry.py b/django/apps/registry.py
index e75bb99cfe..164427d85f 100644
--- a/django/apps/registry.py
+++ b/django/apps/registry.py
@@ -326,8 +326,11 @@ class Apps(object):
         # the relation tree and the fields cache.
         self.get_models.cache_clear()
         if self.ready:
-            for model in self.get_models(include_auto_created=True):
-                model._meta._expire_cache()
+            # Circumvent self.get_models() to prevent that the cache is refilled.
+            # This particularly prevents that an empty value is cached while cloning.
+            for app_config in self.app_configs.values():
+                for model in app_config.get_models(include_auto_created=True):
+                    model._meta._expire_cache()
 
 
 apps = Apps(installed_apps=None)