The Post functions and Validators provided by the JMWE add-on have a
Conditional execution/Conditional Validation section to control the execution of the post-function/validator respectively. You need to provide a Groovy script in the editor based on whose result, the post-function/validator will either be executed or skipped.
On this page:
Conditional execution of a post-function
Expected Value for a condition
The value should be either a boolean value (
false), or more generally any value that will be interpreted as either "truthy" or "falsy". Click on the Expected Value tab of the Groovy editor to know the expected value. You can also quickly test your written script against any issue using the script tester tool. For example:
Groovy expressions returning a "truthy" value:
1 == 1 or any boolean expression that is
issue.get("assignee") if the issue is assigned
issue.getAsString("assignee") == "jdoe" if the issue is assigned to user "jdoe"
issue.get("description") if the issue's description is not empty
Groovy expressions returning a "falsy" value:
Any value will be interpreted as "falsy" (the equivalent of
false) except: true, a non-empty string, a non-empty Collection, a non-empty Map, a non-empty array, a number different from zero (
For example, false, 0, "", 
Below are a few use cases that detail the usage of these functionalities.
Automatically escalate an issue if it is being raised with a "Blocker" priority.
Auto-assign a created issue to the Product owner, only if the issue is a Bug
Add a comment on the Epic when its user stories of a client-side project are resolved.
Allow the members of the
Managers project role to omit the comment
Force the user to provide a Fix Version/s on resolving a bug, only when the resolution is "Fixed"