From 746c4ec5eab339bb278c185d855cd3cd0f67f281 Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Wed, 28 Aug 2024 11:59:15 -0500
Subject: [PATCH] Short-circuit last_activity on unsaved FlowSession to avoid
 Django error

---
 course/models.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/course/models.py b/course/models.py
index 2b7c08295..adc33598b 100644
--- a/course/models.py
+++ b/course/models.py
@@ -973,6 +973,9 @@ def answer_visits(self):
         return assemble_answer_visits(self)
 
     def last_activity(self) -> datetime.datetime | None:
+        if self.pk is None:
+            return None
+
         for visit in (FlowPageVisit.objects
                 .filter(
                     flow_session=self,