Code error, please correct

In your latest version 6.0.0 you’re doing the following:

File: /lib/bambora-online-classic-helper.php

public static function get_bambora_online_classic_subscription_id( $subscription ) {
		$bambora_subscription_id = $subscription->get_meta(
			self::BAMBORA_ONLINE_CLASSIC_SUBSCRIPTION_ID,
			true
		);

		//For Legacy
		if ( empty( $bambora_subscription_id ) ) {
			$parent_order_id         = $subscription->get_parent_id();
			$parent_order            = wc_get_order( $parent_order_id );
			$bambora_subscription_id = $parent_order->get_meta(
				self::BAMBORA_ONLINE_CLASSIC_SUBSCRIPTION_ID_LEGACY,
				true
			);
			if ( ! empty( $bambora_subscription_id ) ) {
				//Transform Legacy to new standards
				$subscription->update_meta_data(
					self::BAMBORA_ONLINE_CLASSIC_SUBSCRIPTION_ID,
					$bambora_subscription_id
				);
				$subscription->save();
				$parent_order->delete_meta_data(
					self::BAMBORA_ONLINE_CLASSIC_SUBSCRIPTION_ID_LEGACY
				);
				$parent_order->save();
			}
		}

		return $bambora_subscription_id;
	}

On line 187 you’re assuming there’s a parent_order available, but if for some reason that parent order has been deleted, the code will throw a PHP Fatal.

The correct code would be:

public static function get_bambora_online_classic_subscription_id($subscription)
    {
        $bambora_subscription_id = $subscription->get_meta(
            self::BAMBORA_ONLINE_CLASSIC_SUBSCRIPTION_ID,
            true
        );

        //For Legacy
        if (empty($bambora_subscription_id)) {
            $parent_order_id         = $subscription->get_parent_id();
            $parent_order            = wc_get_order($parent_order_id);
            if($parent_order) {
                $bambora_subscription_id = $parent_order->get_meta(
                    self::BAMBORA_ONLINE_CLASSIC_SUBSCRIPTION_ID_LEGACY,
                    true
                );
                if (! empty($bambora_subscription_id)) {
                    //Transform Legacy to new standards
                    $subscription->update_meta_data(
                        self::BAMBORA_ONLINE_CLASSIC_SUBSCRIPTION_ID,
                        $bambora_subscription_id
                    );
                    $subscription->save();
                    $parent_order->delete_meta_data(
                        self::BAMBORA_ONLINE_CLASSIC_SUBSCRIPTION_ID_LEGACY
                    );
                    $parent_order->save();
                }
            }
        }

        return $bambora_subscription_id;
    }