[SOLVED] Fabrik 3.9.2 system plugin causes ERROR 500 in admin section

[vpx]

Hello,
I have an up-to-date joomla (v3.9.23). Just after the upgrade to this joomla version, the administrator section is returning a HTTP ERROR 500 while the frontend remains visible.
After a few searches I found that deleting the /plugins/system/fabrik folder solves the issue. But of course that is not an option.
I tried deleting the folder and reuploading the plg_fabrik_system_3.9.2.zip package but this does not help.
How to solve this?
Thanks in advance for your help.

 

[troester]

I can't replicate. I just tried with 2 different sites without problem.

Enable Joomla's error reporting, hopefully you'll get more than just error 500.

Is Joomla the only update you did? Or also other components, templates, php versions...

E.g. a Gantry template?
https://fabrikar.com/forums/index.php?threads/fatal-error-on-admin.51977/

 

[vpx]

Hello @troester thanks for your reply, I am indeed using the G5_Helium template with Gantry v5.4.36.
But the template is working fine without Fabrik.
The debug shows this error in the backend when the Fabrik system plugin is active:

Fatal error: Cannot declare class Joomla\CMS\Form\FormField, because the name is already in use in [MyHostingPathToRoot]/administrator/components/com_fabrik/classes/39/FormField.php on line 22
​

Any idea how to solve this?
EDIT: I just saw the following suggestion, I'll try this:

One thing you could try is making sure that the Fabrik system plugin loads first. We have to override the standard JForms file in order to provide the "repeat" settings on the backend. So if something else explicitly includes that J! file before our plugin gets to it, this can cause issues.

Using a database client of your choice (like phpMyAdmin), in the #__extensions table, find the row with 'name' plg_fabrik_system, and set the 'order' to -1.
​

EDIT 2: I can confirm the previous solution solves the issue.

 

[davez]

I can confirm the solution above as well. Ouch! All I use nowadays is Gantry.