explains Array.wrap directly, rather by comparison with Kernel#Array which is too obscure, leaves the comparison to document the differences, and adds a comparison with the related idiom that uses the splat operator

I am working on removing all traces of superclass_delegating_accessor from rails code base.

https://rails.lighthouseapp.com/projects/8994/tickets/2914-superclass_delegating_accessor-needs-to-be-deprecated-nicely

adds test coverage for edge-cases of Array.wrap, and better documentation for how it differs from Kernel#Array

camelize and underscore are sort of inverse of each other, but not in a mathematical sense [#5174 state:resolved]

camelize and underscore are sort of inverse of each other, but not in a mathematical sense [#5174 state:resolved]

The former should be symmetric with ancestors and include all children. However, it should not include self since ancestors + descendants should not have duplicated. The latter is symmetric to superclass in the sense it only includes direct children.

By adopting a convention, we expect to have less conflict with other frameworks, as Datamapper. For this moment, to ensure ActiveModel::Validations can be used with Datamapper, we should always call ActiveSupport::DescendantsTracker.descendants(self) internally instead of self.descendants avoiding conflicts.