Fixes #20290: Prevent ObjectType queries when table doesn't exist

In v4.4.0, ObjectType became a concrete model with a database table. Signal
handlers query this table during migrations, but the table doesn't exist yet
during 3.7.x→4.4.0 upgrades.

The query failures poison the transaction and abort migrations.

Added objecttype_table_exists() helper and three table existence checks:
- has_feature() in netbox/models/features.py
- update_object_types() in core/signals.py
- Search backend cache() in search/backends.py

If core_objecttype table doesn't exist, operations return early instead of
querying. Once table exists, normal operation resumes.

netbox/core/signals.py

@@ -13,6 +13,7 @@ from django_prometheus.models import model_deletes, model_inserts, model_updates
 from core.choices import JobStatusChoices, ObjectChangeActionChoices
 from core.events import *
 from core.models import ObjectType
+from utilities.object_types import objecttype_table_exists
 from extras.events import enqueue_event
 from extras.models import Tag
 from extras.utils import run_validators
@@ -51,6 +52,10 @@ def update_object_types(sender, **kwargs):
     """
     Create or update the corresponding ObjectType for each model within the migrated app.
     """
+    # Skip ObjectType operations if the table doesn't exist yet (during migrations)
+    if not objecttype_table_exists():
+        return
+
     for model in sender.get_models():
         app_label, model_name = model._meta.label_lower.split('.')
 

netbox/netbox/models/features.py

@@ -24,6 +24,7 @@ from netbox.registry import registry
 from netbox.signals import post_clean
 from netbox.utils import register_model_feature
 from utilities.json import CustomFieldJSONEncoder
+from utilities.object_types import objecttype_table_exists
 from utilities.serialization import serialize_object
 
 __all__ = (
@@ -670,6 +671,10 @@ def has_feature(model_or_ct, feature):
     """
     Returns True if the model supports the specified feature.
     """
+    # Check if ObjectType table exists before attempting queries
+    if not objecttype_table_exists():
+        return False
+
     # If an ObjectType was passed, we can use it directly
     if type(model_or_ct) is ObjectType:
         ot = model_or_ct

netbox/netbox/search/backends.py

@@ -15,6 +15,7 @@ from netaddr.core import AddrFormatError
 from core.models import ObjectType
 from extras.models import CachedValue, CustomField
 from netbox.registry import registry
+from utilities.object_types import objecttype_table_exists
 from utilities.object_types import object_type_identifier
 from utilities.querysets import RestrictedPrefetch
 from utilities.string import title
@@ -209,6 +210,10 @@ class CachedValueSearchBackend(SearchBackend):
                         break
 
                 # Prefetch any associated custom fields
+                # Skip if ObjectType table doesn't exist yet (during migrations)
+                if not objecttype_table_exists():
+                    return
+
                 object_type = ObjectType.objects.get_for_model(indexer.model)
                 custom_fields = CustomField.objects.filter(object_types=object_type).exclude(search_weight=0)
 

netbox/utilities/object_types.py

@@ -1,8 +1,11 @@
+from django.db import connection
+
 from .string import title
 
 __all__ = (
     'object_type_identifier',
     'object_type_name',
+    'objecttype_table_exists',
 )
 
 
@@ -27,3 +30,13 @@ def object_type_name(object_type, include_app=True):
     except AttributeError:
         # Model does not exist
         return f'{object_type.app_label} > {object_type.model}'
+
+
+def objecttype_table_exists():
+    """
+    Check if the core_objecttype table exists.
+
+    Returns True if the table exists, False otherwise.
+    Used to prevent ObjectType queries during migrations when the table doesn't exist yet.
+    """
+    return 'core_objecttype' in connection.introspection.table_names()