Resolving gs.eventqueue Issues in ServiceNow Scoped Applications

[Amit Gujarathi]

Resolving gs.eventqueue Issues in ServiceNow Scoped Applications

In this article, we delve into a specific technical challenge faced by developers: an issue with gs.eventqueue in scoped applications when executed from a business rule containing a nested function.

Problem Description

We have encountered a peculiar problem in ServiceNow's scoped applications. When a business rule with a nested function calls gs.eventqueue, a global script include, the arguments unexpectedly shift one position to the right. This anomaly results in the creation of incorrect sysevent records. Interestingly, this issue does not manifest when using the script debugger, which operates in interpreted mode.

Cause Analysis

This problem stems from two main causes. First, the ServiceNow platform has an issue handling the syntax of nested functions within scoped business rules, particularly when executed in non-interpreted mode. Second, the script debugger, by design, runs in interpreted mode, which does not replicate this syntax issue, thereby masking the problem during debugging sessions.

Resolution and Workarounds

The recommended approach to tackle this issue involves several strategic workarounds:

• Developers should avoid using nested functions within scoped business rules.

• If nested functions are present, they should be moved outside the parent function within the same business rule, as demonstrated in the following examples:

1. Problematic Code Example:

   (function executeRule(current, previous /*null when async*/) {
       // More code here that contains a call to thisWillBreak
       // and a global script include that calls gs.eventqueue
   
       function thisWillBreak() {};
   
   })(current, previous);
   ​

2. Corrected Code Example:

   (function executeRule(current, previous /*null when async*/) {
       // More code here
   })(current, previous);
   
   function thisWillWork() {};
   ​

• Additionally, using script includes to encapsulate additional functionality is a beneficial practice.

Conclusion

This article highlights the importance of adapting to platform-specific nuances and encourages developers to embrace best practices for coding. This not only ensures the stability and reliability of the platform but also enhances the developer's ability to create efficient and error-free applications.

[Ishant Arora]

Informative and helpful post