Add backtrace to all errors

+1 and thank you for the wonderful #301 patch. Don't forget to turn backtrace in settings at admin/config/development/logging after patch applied

Actually additions made in patch at #301 may cause crash below in theme_dblog_message() when the exception's class is not a standard one:
Object of class __PHP_Incomplete_Class could not be converted to string

As $error['exception'] is no longer used after getting its trace, I suggest we unset it then.

This new patch only adds: unset($error['exception']);

<?php
  if (isset($error['exception'])) {
    $e = $error['exception'];
    unset($error['exception']); // HERE
  }
  else {
    $e = new Exception();
  }
?>

Actually, even with my patch, some exceptions still cause what I described at #311.
I guess patch at #301 needs to be rethought to avoid this.

This new patch seems to work in all cases :-)

The 'exception' attribute is now added in _drupal_exception_handler() and directly in _drupal_decode_exception().