症状

The following exception appears when browsing a parent issue which has sub-tasks:

An error occurred whilst rendering this message. Please contact the
administrators, and inform them of this bug. Details: -------
org.apache.velocity.exception.MethodInvocationException: Invocation of
method 'getSubTaskFieldHtml' in class
com.atlassian.jira.web.util.SubTaskQuickCreationWebComponent threw
exception class java.lang.NullPointerException : null 
at org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:246) 
at org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:175) 
at org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:220)
...

Looking at the logs, the following error message appears:

...
java.lang.NullPointerException
at com.atlassian.jira.issue.fields.AssigneeSystemField.makeAssigneeOptionsList(AssigneeSystemField.java:428)
at com.atlassian.jira.issue.fields.AssigneeSystemField.getAssigneeOptionsList(AssigneeSystemField.java:367)
...

原因

User records exist inside the userbase table but not in the membershipbase table. One of the missing/duplicate users are inside the standard groups (jira-users, jira-developers, and jira-administrators), and one of those groups is added to the Assignable Users permission. These errors when browsing a parent issue which has sub-tasks due to this null pointer.

ソリューション

To fix this problem:

1. Run this SQL query:

   
   select user_name from membershipbase where user_name not in (select username from userbase);
   

   The results thrown will be either missing/duplicate users that does not exist in userbase table but existed in membershipbase table.
2. Delete this user with the following SQL query:

   
   delete from membershipbase where user_name not in (select username from userbase);
   

3. Jira を再起動します。