From 2d7d105ba32e2a9cfd60a07c44ab6c748ddb30ff Mon Sep 17 00:00:00 2001
From: Albrecht Degering <albrecht@degering.name>
Date: Tue, 21 Jul 2026 12:34:34 +0200
Subject: [PATCH] Use explicit outbox source validation

---
 src/govoplan_calendar/backend/outbox.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/govoplan_calendar/backend/outbox.py b/src/govoplan_calendar/backend/outbox.py
index d59a9c2..bade245 100644
--- a/src/govoplan_calendar/backend/outbox.py
+++ b/src/govoplan_calendar/backend/outbox.py
@@ -1114,7 +1114,8 @@ def execute_calendar_outbox_operation(
         )
         return operation
 
-    assert source is not None
+    if source is None:
+        raise ValueError("Calendar outbox source is no longer available")
     operation_metadata = operation.metadata_ or {}
     overwrite = (
         bool(operation_metadata.get("overwrite"))