# Codelist migration optimization

* adds boolean to de-/activate migration logic inside of 0002_migrate_975_to_288.py

codelist/migrations/0002_migrate_975_to_288.py

@@ -1,5 +1,6 @@
 # Generated by Django 5.0.7 on 2024-08-06 13:40
 
+from django.core.exceptions import ObjectDoesNotExist
 from django.db import migrations
 from django.db.models import Q
 
@@ -10,9 +11,12 @@ def migrate_975_to_288(apps, schema_editor):
     KonovaCodeList = apps.get_model('codelist', 'KonovaCodeList')
     CompensationState = apps.get_model('compensation', 'CompensationState')
 
-    list_288 = KonovaCodeList.objects.get(
-        id=CODELIST_BIOTOPES_EXTRA_CODES_FULL_ID
-    ).codes.all()
+    try:
+        list_288 = KonovaCodeList.objects.get(
+            id=CODELIST_BIOTOPES_EXTRA_CODES_FULL_ID
+        ).codes.all()
+    except ObjectDoesNotExist:
+        raise AssertionError("KonovaCodeList 288 does not exist. Did you run 'update_codelist' before migrating?")
 
     states_with_extra_code = CompensationState.objects.filter(
         ~Q(biotope_type_details=None)
@@ -42,8 +46,15 @@ class Migration(migrations.Migration):
 
     dependencies = [
         ('codelist', '0001_initial'),
+        ('compensation', '0003_auto_20220202_0846'),
     ]
 
-    operations = [
-        migrations.RunPython(migrate_975_to_288)
-    ]
+    # If migration of codelist is not necessary, this variable can shut down the logic whilst not disturbing the
+    # migration history
+    EXECUTE_CODELIST_MIGRATION = True
+
+    operations = []
+
+    if EXECUTE_CODELIST_MIGRATION:
+        operations.append(migrations.RunPython(migrate_975_to_288))
+