Question

I have defined a model Item which is subclass of ActiveRecord::Base
It has a association attribute called buyer which is a member

It has a buy method to update the buyer attribute.

# do buy transaction on that item
def buy(people_who_buy, amount)
  buyer = people_who_buy
  save
  ....
end

This code cannot update the buyer attribute. The sql generate only do sql selection of member from the database.

But after I add self. before buyer , it works fine.

# do buy transaction on that item
def buy(people_who_buy, amount)
  self.buyer = people_who_buy
  save
  ....
end

It looks weird!

Answer 1

Calling self.write_accessor is required when calling a write_accessor, while in self.read_accessor the self can be omitted (and usually is avoided to keep the code a clean as possible).

---

From the community-edited ruby styleguide:

Avoid self where not required. (It is only required when calling a
self write accessor.)

# bad
def ready?
  if self.last_reviewed_at > self.last_updated_at
    self.worker.update(self.content, self.options)
    self.status = :in_progress
  end
  self.status == :verified
end

# good
def ready?
  if last_reviewed_at > last_updated_at
    worker.update(content, options)
    self.status = :in_progress
  end
  status == :verified
end