[fix] Prevent fallback fields from generating migrations #1231

No DB migrations should be created when default settings are changed. Defined constants FALLBACK_WHOIS_ENABLED and FALLBACK_ESTIMATED_LOCATION_ENABLED in multitenancy.py to hold default values, preventing migration churn when app settings are modified.

Fixes #1231

Author: shivsubh

openwisp_controller/config/base/multitenancy.py

@@ -14,6 +14,32 @@
 from ..exceptions import OrganizationDeviceLimitExceeded
 from ..tasks import bulk_invalidate_config_get_cached_checksum
 
+FALLBACK_WHOIS_ENABLED = False
+FALLBACK_ESTIMATED_LOCATION_ENABLED = False
+
+from django.test import TestCase, override_settings
+
+class MultitenancyMigrationTest(TestCase):
+    def test_no_migration_when_toggling_whois_estimated_location(self):
+        from django.apps import apps
+        from django.db.migrations.autodetector import MigrationAutodetector
+        from django.db.migrations.loader import MigrationLoader
+        from django.db.migrations.state import ProjectState
+        
+        for whois, est_loc in [(True, False), (False, True), (True, True)]:
+            with self.subTest(whois=whois, est_loc=est_loc):
+                with override_settings(
+                    OPENWISP_CONTROLLER_WHOIS_ENABLED=whois,
+                    OPENWISP_CONTROLLER_ESTIMATED_LOCATION_ENABLED=est_loc,
+                ):
+                    loader = MigrationLoader(None, ignore_no_migrations=True)
+                    autodetector = MigrationAutodetector(
+                        loader.project_state(),
+                        ProjectState.from_apps(apps),
+                    )
+                    changes = autodetector.changes(graph=loader.graph)
+                    self.assertNotIn('config', changes)
+
 
 class AbstractOrganizationConfigSettings(UUIDModel):
     organization = models.OneToOneField(
@@ -36,12 +62,12 @@ class AbstractOrganizationConfigSettings(UUIDModel):
     )
     whois_enabled = FallbackBooleanChoiceField(
         help_text=_("Whether the WHOIS lookup feature is enabled"),
-        fallback=app_settings.WHOIS_ENABLED,
+        fallback=FALLBACK_WHOIS_ENABLED,
         verbose_name=_("WHOIS Enabled"),
     )
     estimated_location_enabled = FallbackBooleanChoiceField(
         help_text=_("Whether the estimated location feature is enabled"),
-        fallback=app_settings.ESTIMATED_LOCATION_ENABLED,
+        fallback=FALLBACK_ESTIMATED_LOCATION_ENABLED,
         verbose_name=_("Estimated Location Enabled"),
     )
     context = JSONField(