civicrm/civicrm-core — pull request #2172 by davecivicrm (2013-12-06 03:52:17+00:00)
Title: CRM-13919 - Add form rule to prevent fatal error when user enters a dupl...

...ice trxn_id (there is a unique index on that column in civicrm_contribution table).

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* CRM-13919: Fatal error when user accidentally uses duplicate transaction # while recording a contrib.
http://issues.civicrm.org/jira/browse/CRM-13919