See reportings in http://forum.piwik.org/read.php?2,78979
Goals plugin on dashbaord Fatal error: Class 'Piwik_DataTable_Filter_AddColumnsProcessedMetrics' not found in /home/piwik/public_html/core/DataTable/Filter/AddColumnsProcessedMetricsGoal.php on line 18
The class 'Piwik_DataTable_Filter_AddColumnsProcessedMetrics' that 'Piwik_DataTable_Filter_AddColumnsProcessedMetricsGoal' is trying to extend doesnt appear to be loaded.
By adding class 'Piwik_DataTable_Filter_AddColumnsProcessedMetrics' to '/core/DataTable/Filter/AddColumnsProcessedMetricsGoal.php' allows the class 'Piwik_DataTable_Filter_AddColumnsProcessedMetricsGoal' to extend and then the Goals plugin works.
Adding the following code before trying to extend the class fixes the issue as a temporary solution:
if (!class_exists('Piwik_DataTable_Filter_AddColumnsProcessedMetrics', false))
I think some sort of check for dependent classes should be introduced and should fail during automated tests.
Keywords: class extends epic fail
This is in version 1.5.1 of Piwik (updated 3 days ago)