Module: Errgonomic::Rails::ActiveRecordOptional

Extended by:

ActiveSupport::Concern

Defined in:

lib/errgonomic/rails/active_record_optional.rb

Overview

Concern to make ActiveRecord optional attributes and associations return an Option.

Four pragmatic compromises below satisfy ActiveRecord's assumptions about how accessors behave. They are deliberate exceptions to "Option behaves like Rust's Option", and the set is closed: a fifth would be a signal that ActiveRecord is pushing back somewhere unmapped, deserving a design discussion rather than a quiet patch.

1. None#nil? answers true, so AR internals and ordinary nil checks treat an absent value as absent. Equality does not follow suit: None() == nil stays false.
2. Some delegates persisted?, marked_for_destruction?, and touch_later to its record, so a Some can stand in for it during persistence.
3. Two quoting prepends unwrap Options at the SQL boundary, so an Option can be passed to where/quote.
4. SomeValidator provides a presence-style validation for Option attributes.