Why is validateTransition so picky?

[zaphnet]

I implemented a script runner post action that was intended to transition all subtasks.

The script works fine, but fails for some subtasks. After investigation I find that those issues are commented or has previously been commented by a user that was deleted from the system.

Yes I know users should not be deleted, but this seems to be one of those manual mistakes that happens in a large organization.

After recreating the user the script runs fine.

But I don't understand why the validator prevents transition because of an old comment? 

Manual transition does not care?

import com.atlassian.jira.component.ComponentAccessor

def issueService = ComponentAccessor.getIssueService()
def user = ComponentAccessor.getJiraAuthenticationContext().getLoggedInUser()


def subTasks = issue.getSubTaskObjects()
subTasks.each {
    
    if (it.statusObject.name == "Open") {
        def issueInputParameters = issueService.newIssueInputParameters()
        issueInputParameters.with {
            setSkipScreenCheck(true)
        }

        // validate and transition subtask        
        def validationResult = issueService.validateTransition(user, it.id, 21, issueInputParameters)
        if (validationResult.isValid()) {
            def issueResult = issueService.transition(user, validationResult)
            if (!issueResult.isValid()) {
                log.warn("Failed to transition subtask ${it.key}, errors: ${issueResult.errorCollection}")
            }
                
        } else {
            log.warn("Could not transition subtask ${it.key}, errors: ${validationResult.errorCollection}")
        }
    }
}

[zaphnet]

Investigating it a bit further I realize that the validateTransition throws an exception.

Able to try/catch and implement a workaround.

Still not clear why the validation needs to check the comments of an issue to perform a Transition?