PropertyMapper will throw exception on validating classes without a constructor
If DTO class is used in a form, that has no constructor (and does not inherit from "AbstractEntity") and a property is missing (because the developer forgot to add it to the class), the property mapper will not show meaningfull errors about the property but instead throw the following exception:
#1297759968: Exception while property mapping at property path "": Method Cyberhouse\ExtensionName\Domain\Dto\TestForm::__construct() does not exist
In case a property is missing, the PropertyMapper automatically expects the class to have a constructor when handling the error. If all properties are present in the class, everything works fine without a constructor (submitting forms, validating, etc.), so I will treat this as a bug in the PropertyMapper.
#1 Updated by Christian Eßl 27 days ago
Appears to be longer the case in TYPO3 10.3.
Now you will get a much more meaningful error on implementation errors like:
Exception while property mapping at property path "": Property "firstName" had no setter or constructor argument in target object of type "Cyberhouse\ ExtensionName\Domain\Dto\ TestForm".
It looks like a constructor is no longer mandatory on objects validated by the PropertyMapper.
So this ticket can be closed.