Mandantory content in custom field on table item is not copied on renewal

-- HikaShop version -- : 4.4.2
-- Joomla version -- : 3.1.2
-- PHP version -- : 7.4.18

We are since years a happy customer of hikashop and hikaserial
Lastly we added hikasubscription to our shop to provide some subscription services, obviously.

While configuring and testing the features we encountered a problen, that we could not solve so far:
We created a subscription plan and assigned it to a product.. The relation type is "creation then renewal".
Ordering a subscription of this product assignes a mandantory field (type text) to the ordered product which must be filled with licensing information by the customer.

The order and activation of this subscription works fine so far. But whenever we try to renew a subscription we face an error which states that information which is required for the product is missing. It displays the error message of our mandantory custom field.

Any idea of how to solve this?

We expect that any information (even from custom fields) gets copied to the renewal order.

Thanks in advance for your kind support and speedy help.

Sven Mitscherlich
CamModelTools

At the moment we only want to use manual renewal.
During my tests this happens when I click on Renew in frontend in subscription listing.

The problem is, that the information in the field is needed to activate a temporary license for the usage of our software.

Thanks for your support.

Thanks so far for guiding me in the right direction
Before I start to write a new plugin, I want to share my idea and questions.
Is it correct if I suppose that the event onBeforeSubscriptionUpdate gets fired while renewal (just before the reneval gets executed)?
Is it correct if I suppose thate the optimal event to get the information of my custom field is onSubscriptionActivation?

Where to store this data? In hikaserial_subscription.subscription_extradata?

If I understand the event handling right, then it might be possible to save the value of our custom field when the payment gets approved and the subscription gets activated. This would also make it possible to feed the field value to the new order created for renewal ...

If these assumptions are not correct then please give me some hints on how to implement that custom plugin. I have already read the corresponding technical documentation and tried to understand the both template plugins (acymailingsubscriber and groupsubscriber) but I have to admit that my native language is not php I speak and understand much better C# ... lol ...

Thanks again for your support
Sven Mitscherlich

Hello Jerome,
thanks for your help!! ... I think I can now start to implement my special plugin. I hope you don't mind if I continue to ask questions if any further problem comes up (hopefully not). I let you know how it works out and how far I came with my implementation.

Jerome wrote: Hello,
(...)

I'm a C (and Asm) programmer at start
(...)

Hello Jerome,
... sorry, but I am a complet php noob
can you please put light on my knowledge and tell me please on how to access the order and the order_products objects within a plugin??
I tried as good as possible to find out but to no avail ... sry.

Again thanks in advance for your help
Sven

Hello Jerome,
thanks for the hint in the right direction. Now all is simple and is working like a charm!!

For the community and as a reference I share the php code of that little plugin. It is really easy to adapt it to any need.

<?php
/**
 * @author     CamModelTools
 * @copyright  (C) 2021-2021 CamModelTools. All rights reserved.
 * @license    GNU/GPLv3 http://www.gnu.org/licenses/gpl-3.0.html
 */
defined('_JEXEC') or die('Restricted access');

class plgHikaserial<nameofplugin> extends hikaserialPlugin {
	protected $type = 'ext';
	protected $multiple = false;
	protected $name = '<nameofplugin>';

	public function onBeforeSubscriptionCreate(&$subscription, &$do) {
		/* echo '<pre>'; var_dump($subscription->orders[0]->cart->products[0]->name_of_extra_field); echo '</pre>'; */
		$special_data = @$subscription->orders[0]->cart->products[0]->name_of_extra_field;
		if(!empty($special_data))
		{
			if(empty($subscription->subscription_extradata))
				$subscription->subscription_extradata = array();
			$subscription->subscription_extradata['name_of_extra_field'] = $special_data;
		}
	}
}