Issue with sub-classes

[krismartin]

I've got an issue when using the autoinc with sub-classes.

For example:

class Vehicle field :number, type: Integer increments :number end

class Car < Vehicle end

class Truck < Vehicle end

Because the increment! method uses class.model_name, it treats the sub-classes as two different entities. When I create new Car, increment! returns 1. When I create new Truck, increment! also returns 1 and so on. So the numbers are being duplicated.

This behaviour probably works for most cases, but in my case I need the number to be unique. Plus we also have a unique database constraint on the number field.

One possible option to fix this is to allow the sub-classes to define :model_name (or :class_name) in the increments declaration.

For example:

class Car < Vehicle increments :number, model_name: "Vehicle" end

I'd like to hear your thoughts before I create a pull request. What do you think?

[matsimitsu]

I'd go with an option like

increments :number, :use_inherited_class_name => true or something like that. Being able to define the class name is potentially dangerous as it can screw up the counts if you forget to change it, while use_inherited_class_name works automatically.

@suweller what do you think?

[krismartin]

That's a better option! I like it.