Unable to link multiple tickets to the same parent ticket.

[Mike-Benoit]

Prerequisites

• [Yes] Can you reproduce the problem in a fresh installation of the "develop" branch?
• [Yes] Do you have any errors in the PHP error log, or javascript console?
• [Yes] Did you check the osTicket forums?
• [Yes] Did you perform a cursory search to see if your bug or enhancement is already reported?

Description

Unable to link multiple tickets to a single parent ticket.

[Description of the bug or feature]

Steps to Reproduce

1. Have Ticket A (parent), Ticket B (child 1), Ticket C (child 2).
2. Link Ticket B to Ticket A (success)
3. Link Ticket C to Ticket A (PHP fatal error as shown below)

Expected behavior: [What you expected to happen]

Link multiple tickets to a single parent ticket.

Actual behavior: [What actually happened]

PHP Fatal error: Uncaught Error: Call to a member function getMergeType() on null in /var/www/osticket/include/class.ticket.php:2539\n
Stack trace:\n#0 /var/www/osticket/include/ajax.tickets.php(429): Ticket::merge(Array)\n
#1 /var/www/osticket/include/class.dispatcher.php(145): TicketsAjaxAPI->updateMerge('92880')\n
#2 /var/www/osticket/include/class.dispatcher.php(38): UrlMatcher->dispatch('92880/merge', Array)\n
#3 /var/www/osticket/include/class.dispatcher.php(120): Dispatcher->resolve('92880/merge', Array)\n
#4 /var/www/osticket/include/class.dispatcher.php(38): UrlMatcher->dispatch('/tickets/92880/...', NULL)\n
#5 /var/www/osticket/scp/ajax.php(308): Dispatcher->resolve('/tickets/92880/...')\n
#6 {main}\n thrown in /var/www/osticket/include/class.ticket.php on line 2539, referer: https://helpdesk.mycompany.com/scp/tickets.php?id=92880

Versions

v1.14.1

[JediKev]

@Mike-Benoit

I cannot replicate the issue you are experiencing, I can Link as many tickets together as I want regardless if I do them all at once or separately. Please provide exact steps to replicate the issue.

Cheers.

[Mike-Benoit]

I seem to be able to replicate it on a consistent basis. Checking the code where the fatal error occurred, there appears to be at least an error condition that isn't handled:

   function merge($tickets) {
        $options = $tickets;
        if (!$tickets = self::manageMerge($tickets))
            return false;
        if (is_bool($tickets))
            return true;

        $children = array();
        foreach ($tickets as $ticket) {
            if ($ticket->isParent())
                $parent = $ticket;
            else
                $children[] = $ticket;
        }

        if ($parent->getMergeType() != 'visual') {

Its looping through all the tickets passed in to this function and pulling out the parent and children. If there isn't a parent ticket in there, it will throw a fatal error on that last line.

Of course I'm not sure why there isn't a parent ticket when we're doing the linking, but its definitely a scenario that is happening and should probably be checked.

[JediKev]

@Mike-Benoit

Right, which is why I asked for exact steps to replicate so we can attempt to replicate the issue.

Cheers.

[Mike-Benoit]

I'm having a hard time narrowing it down.

When I get the PHP fatal error, simply swapping the parent/child order when linking the ticket appears to avoid the issue. So when viewing a ticket and performing the link to another ticket, the ticket you are viewing normally defaults to the child, this is where the error occurs, if I switch it to the parent it doesn't occur.

I'm not sure what the significance is with the parent/child relationship when linking, I understand it in a merge case, but for linking it doesn't make a lot of sense to me.

I tried creating three fresh tickets and they linked no problem. So my best guess is its specific to the tickets that are being linked themselves, but I have yet to find the exact set of steps to replicate it from scratch.

[Mike-Benoit]

Any ideas what the circumstances are where when linking a ticket it automatically unlinks other tickets?

Mike Benoit unlinked this ticket from Ticket #673990 13-Jan-2020 5:09 PM
Mike Benoit linked this ticket with Ticket #897070 13-Jan-2020 5:09 PM

As you can see from the above events, I had a ticket linked to 673990, then tried to link it also to 897070, but it unlinked it from 673990 automatically at the exact same time.

[JediKev]

@Mike-Benoit

I don’t think you can link a child to multiple parents. Only multiple children to one parent.

Cheers.

[Mike-Benoit]

Its possible this is related to the following forum post and possibly duplicate thread_entry_id records appearing in multiple tables:
https://forum.osticket.com/d/96658-can-t-view-new-tickets-after-upgrade-to-v1-14-1/7

May also be related to #5339