Script to validate the existence of several custom fields on transition using the ScriptRunner plugin for Jira.

AlmaValidateFields.groovy

import com.opensymphony.workflow.InvalidInputException
import com.atlassian.jira.ComponentManager
import com.atlassian.jira.issue.Issue
import com.atlassian.jira.issue.CustomFieldManager
import com.atlassian.jira.issue.fields.CustomField

def customFieldManager = ComponentManager.getInstance().getCustomFieldManager()
def fields = []

// For Alma issues, if issue is fixed, make all sorts of validations
if (issue.resolution?.name == 'Fixed' && issue.project?.name == 'Alma') {
   switch ( issue.issueType?.name ) {
   	case 'Bug':
    	fields.addAll(['Resolution Description','Fix in Environment'])
    case ['Story', 'Bug', 'Task', 'inList']:
    	fields.addAll(['Documentation Required','Migration Impact','Configuration Impact','Automation Impact','Leganto Documentation Required'])
   }
   fields.each {
		CustomField cf = customFieldManager.getCustomFieldObjectByName(it)
		if (cf && !issue.getCustomFieldValue(cf)) {
			if (invalidInputException)
				invalidInputException.addError(cf.id, "You must specify a value for ${cf.name}.")
			else
				invalidInputException = new InvalidInputException(cf.id, "You must specify a value for ${cf.name}.")
		}
	}
	if (invalidInputException)
		invalidInputException.addError("The fields marked below must be filled before the issue can be resolved.")
} else
   return true