I attached a new custom group to entity type group and added a field of type file. When editing the group settings and fill in a file, it is posted without errors and notification bubble confirms success. But there is no file uploaded.
No error logs even with debugging enabled, file tmp folder is checked and I successfully tried another custom file field attached to entity contact.
Just tried on https://dmaster.demo.civicrm.org/ - same misbehavior.
Looked at the code and it seems that the posted file info is not getting into the params array. Although the posted name is of correct format custom_123_21313 the packages/HTML/QuickForm/Controller.php->exportValues gets "MAX_FILE_SIZE" as key for the custom field. Could it be that https://lab.civicrm.org/dev/core/-/blob/master/CRM/Group/Controller.php's overridden custom file field preparation causes this error?
Civi and Drupal are current versions.
Core Team, do you have a clue? How may I investigate further? Where is the $_POST stuff prepared prior to postProcess in CRM/Group/Form/Edit.php?
