[development] transferring session info across login event

[Daniel F. Kudwien]

> To clarify, the issue I wrote about isn't related to 
> $_SESSION, it's modules that store data in a separate table 
> with session id as the key (as e-commerce does).  It seems 
> this may be a flawed data model unless there is some means 
> for modules to respond to regenerated session ids.

Did you already try:

function mymodule_form_alter($form_id, &$form) {
  if ($form_id == 'user_login' || $form_id == 'user_login_block') {
    $form['submit'] = array('mymodule_pre_submit' => array());
    $form['submit']['mymodule_post_submit'] = array();
  }
}

function mymodule_pre_submit($form_id, $form_values, $return) {
  static $backup = array();
  if ($return) {
    return $backup;
  }
  // Backup session data here
  $backup = ...
  // Invoke user login (hook_user)
  user_login_submit(...);
}

function mymodule_post_submit($form_id, $form_values) {
  // Reset session data
  $restored = mymodule_pre_submit(NULL, NULL, TRUE);
}

? Just an idea.

But yes, dealing with hook_user() forms is quite a mess...