DRAFT SP-7550 Unexpected behavior with a!isNullOrEmpty

Symptoms

a!isNullOrEmpty({null}) returns false

Cause

This is expected product behavior. A set with the element null is not a null set.

Additionally, a!isNullOrEmpty() does not iterate over lists to check for null elements; the purpose of this is to keep the function's performance fast.

Please see the below chart for more examples of expected product behavior regarding a!isNullOrEmpty():

Input	Output
`a!isNullOrEmpty({{}, ""})`	`false`
`a!isNullOrEmpty(cast(197, ""))`	`false`
`a!isNullOrEmpty({tostring(null), tointeger(null)})`	`false`
`a!isNullOrEmpty({null,null})`	`false`

Action

If the value being checked is a list that may contain only null elements, please use the length() or a!forEach() functions

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: August 2022