KB-1794 "Details: ERROR:EVAL:@reason=index" error thrown when using escalations, timers, and exception flows

Symptoms

Events, such as escalations, timers, and exception flows, relying on valid expressions throw an error when activated:

There is a problem with the process "Error on Timer"
Problem: An invalid expression has been encountered.

Details: ERROR:EVAL:@reason=index

Recommended Action: Check the expression including any function requirements and resume.

Priority of this problem: High Priority

Cause

This error occurs when events are configured using expressions that pass in arguments by keyword, for example:

rule!exampleRule(
 time: now(),
 timezone: "EST"
)

As mentioned in the Appian Expressions Documentation, events do not support passing arguments by keyword.

Action

Pass in the arguments by position instead, for example:

rule!exampleRule(
 now(),
 "EST"
)

Affected Versions

This article applies to all versions of Appian.

Last reviewed: December 2019