Duplicate INSERT with the same code_id and user_id in the table wp_pmpro_discount_codes_uses

[ipokkel]

Describe the bug
A customer reported the following:

The plugin allow duplicate INSERT with the same code_id and user_id in the table wp_pmpro_discount_codes_uses which set a wrong available seats and block next sponsored user to register (when the max seats is reach).

This happens here.

pmpro-sponsored-members/pmpro-sponsored-members.php

Line 295 in 89ccaa6

$sqlQuery = "INSERT INTO $wpdb->pmpro_discount_codes_levels (code_id,

Expected behavior
We should consider adding a check to avoid duplicate submissions.

Additional Information
Ticket no. 520675