When Zend_Form throws an exception, it inserts twice the class name within error message.

see the following error message generated by Zend_Form:

{quote}Exception information:

Message: Zend_Form::Zend_Form::isValid expects an arrayencounters a problem, it {quote}

Class Zend_Form is displayed twice because of this code: {quote}throw new Zend_Form_Exception(CLASS . '::' . METHOD . ' expects an array');{quote}

Magic constants METHOD already contains 'CLASS::' therefore prepending it creates a duplicate class name.

Example: class A { public function b() { return METHOD; } }

$a = new A(); echo $a->b(); // output: A::b