Need delayed initializer for self-referential class variables

[alexchandel]

Consider the following example of a class with a class variable that is an instance of itself. It's impossible to reference class names within the immediately body of the class, as the class is not defined yet:

define
class SolverBackend:
    name: SolverName = field(converter=SolverName)

    SCIP: ClassVar[Self] = SolverBackend('scip')  # ERROR

Instead, you have to do something like ths:

@define
class SolverBackend:
    name: str

    SCIP: ClassVar[Self]

SolverBackend.SCIP = SolverBackend('scip')

(This is an extremely simplified example to demonstrate this aspect.) It would be nice to support this natively, with something like:

@define
class SolverBackend:
    name: str

    SCIP: ClassVar[Self] = classvar(factory=lambda: SolverBackend('scip'))

Or maybe just interpret the usual attrs functions appropriately for ClassVar, like:

@define
class SolverBackend:
    name: str

    SCIP: ClassVar[Self] = Factory(lambda: SolverBackend('scip'))

[Tinche]

If I understand correctly, I think this is a neat idea but somewhat out of scope for attrs and a little bit of a niche use case. You could probably do this youself by wrapping @define with your own function and running a little bit of post processing?