When you add this post-function to a transition and trigger the transition on an issue, the add-on increments the selected field value by one. This is applicable to numerical fields only.
Conditional execution
To execute this post-function based on the result of a groovy expression see Conditional execution/validation using a Groovy expression.
Error Handling
By default, all errors (Java Exceptions) raised by this post-function, including those raised by custom Groovy scripts, will be logged in the JIRA log file but will not be reported to the user and will not prevent the transition from completing.
However, when designing new workflows or troubleshooting them, it is more convenient to be notified immediately of any such error during the execution of the transition. On development and staging Jira instances, you can activate error reporting for all JMWE post-functions on the JMWE configuration page, and it is recommended to do so. But on production Jira instances, you might want to show errors only for the post-function(s) being worked on, in order to avoid disrupting other workflows. To make errors raised by the current post-function prevent the transition from completing and show the error in the browser, select Make transition fail when an error occurs in this post-function
.