We have been days without noticing that there was an error in the cron script archive.php
When a scheduled task fails, for example PDF generation returning a PHP warning, the error is not reported upstream in archive.php and then in the output (and emailed if setup in cron).
We should make sure that, when an error is triggered in the scheduled tasks (Exception or random php warning), the piwik SU is notified by email that this failed
(In ) Fixes tcpdf (will report upstream), regression when generating pdf reports containing images that tcpdf was trying to record in piwik tmp folder rather than :
Warning: fopen(/path/piwik/tmp/tcpdf/img_2c44a2e1eb91042bd785a17a4f185524) href='function.fopen'>function.fopen</a>: failed to open stream: No such file or directory in /tcpdf.php on line 7225
(In ) Fixes #2818 - writing errors to php://stderr