DateTime properties cannot be persisted
Using the Blog application with FLOW3 1.0.0 alpha 12 results in an exception when trying to create a new blog post:
#1265367590: Object "DateTime" is not registered. (More information) F3\FLOW3\Object\Exception\UnknownObjectException thrown in file Packages/Framework/FLOW3/Classes/Object/Container/AbstractObjectContainer.php in line 267.
The reason for this is that the validation framework tries to figure out if DateTime has the scope prototype (because it wouldn't create a validator for it otherwise). However, DateTime is not a registered object at the Object Manager. The check for prototype was introduced while solving #9862.
The solution is to pre-register (certain) built-in PHP classes, such as DateTime. I'm not sure at this point for which other classes it would make sense, therefore this is just about fixing the DateTime behavior.