Can't filter objects with missing custom fields values

[david-kn]

Environment

• Python version: Any
• Nautobot version: 1.1.1

Any objects (let's say prefixes) with custom fields can't be filtered any more to search those with missing values.

• When filtering objects with missing value(s) in standard attributes, a value null is used (e.g. /api/ipam/prefixes/?site=null ) - works just fine (OK)
• When filtering objects with missing value(s) in custom fields, I used to use value "0" (zero) which worked well but it does not anymore (e.g. /api/ipam/prefixes/?my_custom_field=0 ) and neither does value null or empty string or anything else.

Steps to Reproduce

1. Let's have objects with custom fields (e.g. my_custom_field ) where some are not filled in
2. Try to filter only those objects where the custom field is not filled in: /api/ipam/prefixes/?my_custom_field=0

Expected behaviour

The objects with missing (empty) value in a given custom fields should have been returned.

Observed Behavior

No objects were returned at all.

[nniehoff]

To clarify this a bit this is specifically the case for custom fields of type Selection. The previous query of ?my_custom_field=0 used to work in NetBox as the query appears to be the index of the choices array with 0 being null. In Nautobot custom fields were refactored and now the URL query specifies the value of the field so the same query is looking for the literal value of 0 not null. While this does seem to be specifically related to the selection field type it seems like being able to query any custom field for null/empty should be a valid query somehow.

[bryanculver]

Merged into next.