Implement a more throughough cache-flush mechanism. This makes sure to flush foreignkey cache relations for objects not affected by flushing (normally objects with an NAttribute stored in them). Without ForeignKey flushing, the location of such objects would remain cached and drift out of sync, leading to content caches in turn desyncing. Resolves #1064.

evennia/typeclasses/models.py

@@ -386,6 +386,14 @@ class TypedObject(SharedMemoryModel):
                 False, don't flush and expect this object to handle
                 the flushing on its own.
 
+        Notes:
+            The default implementation relies on being able to clear
+            Django's Foreignkey cache on objects not affected by the
+            flush (notably objects with an NAttribute stored). We rely
+            on this cache being stored on the format "_<fieldname>_cache".
+            If Django were to change this name internally, we need to
+            update here (unlikely, but marking just in case).
+
         """
         if self.nattributes.all():
             # we can't flush this object if we have non-persistent
@@ -393,6 +401,12 @@ class TypedObject(SharedMemoryModel):
             # we try to flush as many references as we can.
             self.attributes.reset_cache()
             self.tags.reset_cache()
+            # flush caches for all related fields
+            for field in self._meta.fields:
+                name = "_%s_cache" % field.name
+                if field.is_relation and name in self.__dict__:
+                    # a foreignkey - remove its cache
+                    del self.__dict__[name]
             return False
         # a normal flush
         return True