Parsing a PaymentExpanded is causing a parser error

[Eduardo Rigamonte (erigamonte)]

Hello guys,

I’m developing a Checkout Pro integration, and when using the payment search method, I’m encountering a GSON parsing error. This happens because the Payment class maps the attribute PaymentExpanded > Gateway > Reference as an object, but the MercadoPago backend returns it as a string.

Example of the response:

{
...
"reference": "{\"merchant_number\":\"30121999\",\"merchant_transaction_reference\":\"30121999\",\"network_transaction_id\":\"865T55\",\"processed_at\":\"2025-07-02T10:43:54-04:00\",\"processed_at_source\":\"integration\",\"payment_id\":\"1338592189\",\"site_id\":\"MLB\"}",
...
}

As a temporary solution, I worked around the issue by overriding the PaymentClient and Payment classes, and changing the expanded attribute from:

from:

private PaymentExpanded expanded;

to:

private Map<String, Object> expanded;