Custom fields of type 'object' don't work with 'empty' filter expression

[llamafilm]

Deployment Type

Self-hosted

NetBox Version

v4.3.2

Python Version

3.12

Steps to Reproduce

1. Create a custom field called 'location_served' with type 'object (location)' and filter logic 'exact' and object types 'device'. (We use this when a device serves a room other than where it's physically located, for example an AV Closet next to a screening room.)
2. Add some values to this custom field on a few devices.
3. Try to filter /dcim/devices/?cf_location_served__empty=true

Expected Behavior

Since the custom field stores a numeric value, representing the ID of the linked object, it should respect all the numeric lookup expressions. Some expressions do work correctly, for example /dcim/devices/?cf_location_served__gt=18600.

Observed Behavior

It returns all objects, as if the filter were not present.

[llamafilm]

This same bug also applies to custom fields of type 'integer'.

[jnovinger]

This appears to be a legitimate bug where the __empty and __isnull lookup expressions don't work correctly for object-type (or integer) custom fields. We'll need to verify that custom fields were intended to support the documented lookup expressions implementation gap.

In the future, please ensure your report contains complete and accurate reproduction details, including exact field names and correct syntax, as this is crucial for efficient triage.

[llamafilm]

Thanks, I've added some details to the original post.

[jeremystretch]

Related to (and possibly blocked by) FR #18256