Merge branch...

Merge branch '778-migrations-fail-when-chronos-is-installed-no-migrations-were-ever-run-before' into 'master'

Resolve "Migrations fail when Chronos is installed & no migrations were ever run before"

Closes #778

See merge request !1141

aleksis/core/migrations/0047_add_room_model.py

@@ -3,10 +3,12 @@
 from django.apps import apps
 import django.contrib.sites.managers
 from django.db import migrations, models
+from django.db.utils import ProgrammingError
 import django.db.models.deletion
 import django.utils.timezone
 import oauth2_provider.generators
 import oauth2_provider.models
+from psycopg2.errors import UndefinedTable
 
 
 class Migration(migrations.Migration):
@@ -16,9 +18,17 @@ class Migration(migrations.Migration):
         ('core', '0046_notification_create_field_icon'),
     ]
 
+    # This migration must run after Chronos' migration 1 through 12, but before
+    #  13. That's because we are in fact moving a model, and we need to make sure
+    #  that this migration runs at the right time.
     if "chronos" in apps.app_configs:
         recorder = migrations.recorder
-        if not recorder.MigrationRecorder.Migration.objects.filter(app="core", name="0046_add_room_model").exists():
+        applied = False
+        try:
+            applied = recorder.MigrationRecorder.Migration.objects.filter(app="core", name="0046_add_room_model").exists()
+        except ProgrammingError:
+            applied = False
+        if not applied:
             dependencies.append(('chronos', '0012_add_supervision_global_permission'))
 
     operations = [