Null check a reference field in GlideRecord

Reference fields in ServiceNow behave differently than regular fields when they're empty. While you can safely check current.state == 6 on a choice field, trying to access properties on an empty reference like current.assigned_to.email will throw a null pointer exception that crashes your script. The platform doesn't automatically guard against this because reference field objects are lazy-loaded — ServiceNow doesn't know the reference is empty until you try to access it. Always null-check references before accessing their properties or methods.

When to use this

• Before accessing any property or method on a reference field (current.assigned_to.name, current.caller_id.getDisplayValue())
• In Business Rules where reference fields might be empty during record creation or updates
• Before using a reference field value in another GlideRecord query or API call
• When processing records in scheduled jobs where data integrity isn't guaranteed

When NOT to use this

• Don't use nil() in client scripts — it's server-side only. Use g_form.getValue('reference_field') instead
• Don't check references you've just set in the same script — current.assigned_to = userId; current.assigned_to.nil() will still return true
• Don't use this pattern for choice fields or string fields — only reference fields throw null pointer exceptions

Key behaviors and gotchas

• Use !gr.reference_field.nil() or gr.getValue('reference_field') — both return falsy when the reference is empty
• Testing if (current.assigned_to) will throw an exception if the field is empty — the field object itself is null
• Empty reference fields store empty strings in the database, but nil() checks for both empty strings and actual nulls
• ACL restrictions can make reference fields appear empty even when they contain valid sys_ids — always check access rights in complex scenarios
• Cross-scope reference fields may return empty even with valid data if the target table is in a different application scope
• Domain separation affects reference field visibility — records in different domains may appear as empty references