I run into 2 issues and maybe someone have a solution:
isEpic is handled as expensive operation, which makes is not usable within a jql search
the usage of issue.epic will throw the following error: “Unknown error when transforming to bean. Try again and if the problem persists, contact Jira support”
isEpic: as I already know if “PROJ-1” is an epic based on a request before, I can use somethink like this (10005 is the issue ID of PROJ-1) isEpic: [10005].includes(issue.id)
epic: in a request before, I already get all Jira fields (rest/api/2/field) and searched for the field with the scheme “com.pyxis.greenhopper.jira:gh-epic-link”, which is customfield_10014 in my example and use this dynamic generated expression part parent: issue.${epicLinkField.id} || (issue.parent? issue.parent.key: null)
Could you create two separate issues in the ACJIRA project for the problems you described? One feature request for making isEpic compute in constant time for issue collections, and another – a bug for the error thrown when issue.epic is returned from the REST API?