Fix getters for substitutions table schema to work with events that are not amending other events

aleksis/apps/chronos/schema/__init__.py

@@ -153,11 +153,13 @@ class SubstitutionType(graphene.ObjectType):
 
     def resolve_old_groups(root, info):
         le = root["REFERENCE_OBJECT"]
-        return le.amends.groups.all() or le.groups.all()
+        if le.amends and le.amends.groups.all():
+            return le.amends.groups.all()
+        return le.groups.all()
 
     def resolve_new_groups(root, info):
         le = root["REFERENCE_OBJECT"]
-        if le.groups.all() and le.amends.groups.all():
+        if le.groups.all() and le.amends and le.amends.groups.all():
             return le.groups.all()
         else:
             return []
@@ -176,11 +178,13 @@ class SubstitutionType(graphene.ObjectType):
 
     def resolve_old_teachers(root, info):
         le = root["REFERENCE_OBJECT"]
-        return le.amends.teachers.all() or le.teachers.all()
+        if le.amends and le.amends.teachers.all():
+            return le.amends.teachers.all()
+        return le.teachers.all()
 
     def resolve_new_teachers(root, info):
         le = root["REFERENCE_OBJECT"]
-        if le.teachers.all() and le.amends.teachers.all():
+        if le.teachers.all() and le.amends and le.amends.teachers.all():
             return le.teachers.all()
         else:
             return []
@@ -189,30 +193,32 @@ class SubstitutionType(graphene.ObjectType):
         le = root["REFERENCE_OBJECT"]
         if le.name == "supervision":
             return "SUPERVISION"
-        elif not le.amends.subject and not le.subject:
-            return le.amends.title
+        elif not (le.amends and le.amends.subject) and not le.subject:
+            if le.amends:
+                return le.amends.title
+            return le.title
         else:
-            subject = le.amends.subject or le.subject
+            subject = le.amends.subject if le.amends and le.amends.subject else le.subject
             return subject.short_name or subject.name
 
     def resolve_new_subject(root, info):
         le = root["REFERENCE_OBJECT"]
         if le.name == "supervision":
             return None
-        elif not le.amends.subject and not le.subject:
-            return le.title
-        elif le.subject and le.amends.subject:
+        elif le.subject and le.amends and le.amends.subject:
             return le.subject.short_name or le.subject.name
         else:
             return None
 
     def resolve_old_rooms(root, info):
         le = root["REFERENCE_OBJECT"]
-        return le.amends.rooms.all() or le.rooms.all()
+        if le.amends and le.amends.rooms.all():
+            return le.amends.rooms.all()
+        return le.rooms.all()
 
     def resolve_new_rooms(root, info):
         le = root["REFERENCE_OBJECT"]
-        if le.rooms.all() and le.amends.rooms.all():
+        if le.rooms.all() and le.amends and le.amends.rooms.all():
             return le.rooms.all()
         else:
             return []
@@ -221,7 +227,7 @@ class SubstitutionType(graphene.ObjectType):
         return root["REFERENCE_OBJECT"].cancelled
 
     def resolve_notes(root, info):
-        return root["REFERENCE_OBJECT"].title or root["REFERENCE_OBJECT"].comment
+        return root["REFERENCE_OBJECT"].comment
 
 
 class SubstitutionsForDateType(graphene.ObjectType):