Paymill - failed transaction - '' is less than 1 characters long - php

Question

I got stuck with this error for quite a while and I can't figure out how to solve this problem. I double, even triple, checked data passed to transaction object and still can't find out why it keeps throwing me this " '' is less than 1 characters long " error message. I couldn't even find documentation for that error message on the internet.
Brief overview of current state of my code:
My transaction object creation is wrapped in try..catch statement (\Paymill\Services\PaymillException)
Client and Payment objects created correctly. I can see those two on my paymill control panel.
I'm passing shopping cart array to Transaction object as well
Item description is being derived using this sequence:trim(substr(html_entity_decode($item['description']), 0, 123)) . "..."
Payment is being made via credit card
First payment was successful second one fails
here's partial exception object output:
[__PHP_Incomplete_Class_Name] => Paymill\Services\PaymillException
[_errorMessage:Paymill\Services\PaymillException:private] => '' is less than 1 characters long
[_responseCode:Paymill\Services\PaymillException:private] =>
[_httpStatusCode:Paymill\Services\PaymillException:private] => 400
[_rawObject:Paymill\Services\PaymillException:private] =>
[message:protected] => '' is less than 1 characters long
[string:Exception:private] =>
[code:protected] => 400
...
[__PHP_Incomplete_Class_Name] => Paymill\Models\Request\Transaction
[_amount:Paymill\Models\Request\Transaction:private] => 6613
[_description:Paymill\Models\Request\Transaction:private] => Order ID: 111111-11111-1111
[_currency:Paymill\Models\Request\Transaction:private] => EUR
[_payment:Paymill\Models\Request\Transaction:private] => pay_1234566789
[_client:Paymill\Models\Request\Transaction:private] => client_123456
[_preauthorization:Paymill\Models\Request\Transaction:private] =>
[_token:Paymill\Models\Request\Transaction:private] => 123456
[_feeAmount:Paymill\Models\Request\Transaction:private] =>
[_feePayment:Paymill\Models\Request\Transaction:private] =>
[_feeCurrency:Paymill\Models\Request\Transaction:private] =>
[_source:Paymill\Models\Request\Transaction:private] =>
[_shippingAddress:Paymill\Models\Request\Transaction:private] => Array
(
[name] => Full name
[street_address] => full address
[street_address_addition] => N/A
[city] => full city
[state] => state as well
[postal_code] => 123456
[country] => CC
)
[_billingAddress:Paymill\Models\Request\Transaction:private] => Array
(
[name] => Full name
[street_address] => full address
[street_address_addition] => N/A
[city] => full city
[state] => state as well
[postal_code] => 123456
[country] => CC
[phone] => 123456
)
[_items:Paymill\Models\Request\Transaction:private] => Array
(
[0] => Array
(
[name] => full item name
[amount] => 123456
[description] => full description
[quantity] => 1
[item_number] => 123456-1
[url] => https://123123.html
)
...
[_shipping_amount:Paymill\Models\Request\Transaction:private] => 400
[_handling_amount:Paymill\Models\Request\Transaction:private] =>
[_mandateReference:Paymill\Models\Request\Transaction:private] =>
[_id:protected] =>
[_serviceResource:protected] => Transactions/
[_filter:protected] =>
)
[1] => create
)
)
This is how I initiate transaction
$transaction->setClient($this->getClient()->getId())
->setPayment($this->getPayment()->getId())
->setToken($this->getToken())
->setAmount($this->getBasket('total')*100)
->setBillingAddress($billing_address)
->setShippingAddress($shipping_address)
->setCurrency($this->getConfig('currency'))
->setItems($items)
->setDescription("Order ID: " . $this->getBasket('cart_order_id'))
->setShippingAmount($this->getBasket('shipping')['value']*100);
$this->d($this->getClient());
$r = $this->getRequest()->create($transaction);

Answer 1

Problem solved. One of the items was with empty description field. Strange that Exception did not include a field name which was causing problems.