civicrm/civicrm-core — pull request #4552 by anemirovsky (2014-11-13 18:25:19+00:00)
Title: Add hook_civicrm_preProcess function.

This seems to be a generically useful spot to intercept the form object and
change things before the form is processed. Specifically, we need this hook
for integrating the Event Cart with the CiviDiscount extension.