ZF-2012: Validate type of set objects

Description

Whenever a method requires a specific data model element type to be set in the call, the type should be enforced.

For instance, calling $entry->setTitle requires that a Zend_Gdata_App_Extension_Title be used. However, if you set a simple string, everything works with the set, but when saveXML or getDOM gets called, it's difficult to determine what failed-- because something like 'Call to a member function getDOM() on a non-object ...*' is thrown.

Comments

(batch downgrading outstanding issues older than 1 year)

I'm bumping this one back up to major, because this comes up commonly enough that I consider it a serious usability problem.

Bulk change of all issues last updated before 1st January 2010 as "Won't Fix".

Feel free to re-open and provide a patch if you want to fix this issue.