Cannot redeclare Zend_Db_Adapter_Pdo_Mysql::_connect() in library/Zend/Db/Adapter/Pdo/Mysql.php on line 120

this happens because _connect() really is defined twice:

 79     /**
 80      * Creates a PDO object and connects to the database.
 81      *
 82      * @return void
 83      * @throws Zend_Db_Adapter_Exception
 84      */
 85     protected function _connect()
 86     {
 87         if ($this->_connection) {
 88             return;
 89         }
 90
 91         if (!empty($this->_config['charset'])) {
 92             $initCommand = "SET NAMES '" . $this->_config['charset'] . "'";
 93             $this->_config['driver_options'][PDO::MYSQL_ATTR_INIT_COMMAND] = $initCommand;
 94         }
 95
 96         parent::_connect();
 97     }
 98

/.../

117     /**
118      * @return void
119      */
120     protected function _connect()
121     {
122         if ($this->_connection) {
123             return;
124         }
125         parent::_connect();
126         if (array_key_exists('charset', $this->_config)) {
127             $this->_connection->exec('SET NAMES ' . $this->_quote($this->_config['charset']));
128         }
129     }
130

this error could be easily identified by syntax lint: $ php -l library/Zend/Db/Adapter/Pdo/Mysql.php PHP Fatal error: Cannot redeclare Zend_Db_Adapter_Pdo_Mysql::_connect() in library/Zend/Db/Adapter/Pdo/Mysql.php on line 120 Errors parsing library/Zend/Db/Adapter/Pdo/Mysql.php

so perhaps integrate the syntax lint also in your ZF build/release system.

ps: Zend_Db_Adapter_Mysql seems not listed in issue tracker components