Battling something rather interesting in 6.x pressflow, which has backported some of 7.x's error handling.
If the php library imap_open triggers a connection error, when drupal error handling, global variables aren't set ($user is empty) and debug_backtrace only contains one item, e.g. _drupal_error_handler, so once that is removed $backtrace[0] is not set and triggers another error.
I have no idea how to reproduce this condition outside of imap_open; trying to google the situation didn't help at all.
| Attachment | Size | Status | Test result | Operations |
|---|---|---|---|---|
| drupal_error_handler_backtrace.patch | 531 bytes | Idle | PASSED: [[SimpleTest]]: [MySQL] 50,626 pass(es). | View details | Re-test |
| drupal_error_handler_backtrace.6.do-not-test.patch | 912 bytes | Ignored | None | None |