Wikimedia Bugzilla is closed!

PHP's debug_backtrace() function can produce output that is not handled properly
by the wfAbruptExit function.

To illustrate, here is part of the output of doing a var_dump($bt) when running
with the latest PHP4.4 stable CVS snapshot:
=================================================
       }
      }
    }
  }
  [12]=>
  array(4) {
    ["function"]=>
    string(12) "out_revision"
    ["class"]=>
    string(12) "wikiimporter"
    ["type"]=>
    string(2) "->"
    ["args"]=>
    array(2) {
      [0]=>
      &resource(75) of type (xml)
      [1]=>
      &string(8) "revision"
    }
  }
  [13]=>
  array(4) {
    ["file"]=>
    string(62) "/var/www/hosts/local-wikipedia/wiki/includes/SpecialImport.php"
    ["line"]=>
    int(261)
    ["function"]=>
    string(9) "xml_parse"
    ["args"]=>
    array(3) {
      [0]=>
      &resource(75) of type (xml)
      [1]=>
===================================================

Note that $bt[12] does not contain a "file" or "line" key.

A 2-line patch will be attached shortly to add handling for this.