Enums instead constants

[l-you]

Do you plan to replace constants with native enums in v3.0?
For instance in mappings

orm/lib/Doctrine/ORM/Mapping/ManyToOne.php

Lines 27 to 30 in 5fe78f7

	* @var string
	* @Enum({"LAZY", "EAGER", "EXTRA_LAZY"})
	*/
	public $fetch = 'LAZY';

[michnovka]

@derrabus @greg0ire @beberlei Id like to open a discussion under this thread. I think this is the way to go in the future, are there any cases against?

[derrabus]

The only argument against this plan that comes to my mind is that we would force people to update code that is perfectly fine. I'm currently modernizing our attribute classes (see #10145, #10151) and exploring how we can leverage enums is on my todo list.

[michnovka]

@derrabus perhaps we could leverage https://github.com/rectorphp/rector and make rules that would update the code automatically?

Edit: ah, I see this is a thing - https://github.com/rectorphp/rector-doctrine