class RuboCop::Cop::Rails::Pick

[{ a: :b, c: :d }].pick(:a, :b)
Model.pick(:a)
# good
[{ a: :b, c: :d }].pluck(:a, :b).first
Model.pluck(:a).first
# bad
@example
See: github.com/rubocop/rubocop-rails/pull/249<br><br>in Rails 6.1 via rails/rails#38760, at which point the cop is safe.
whereas ‘pick` is only defined on `ActiveRecord::Relation` in Rails 6.0. This was addressed
This cop is unsafe because `pluck` is defined on both `ActiveRecord::Relation` and `Enumerable`,
@safety
care should be taken while resolving this violation.
causes a subquery to be added. In most cases this is undesirable, and
Note that when `pick` is added to a relation with an existing limit, it
limit to the query so that only one value is fetched from the database.
`pick` avoids. When called on an Active Record relation, `pick` adds a
Using `pluck` followed by `first` creates an intermediate array, which
Enforces the use of `pick` over `pluck(…).first`.

def message(receiver, current) 

def message(receiver, current)
  format(MSG, args: receiver.arguments.map(&:source).join(', '), current: current.source)
end

def on_send(node) 

def on_send(node)
  pick_candidate?(node) do
    receiver = node.receiver
    receiver_selector = receiver.loc.selector
    node_selector = node.loc.selector
    range = receiver_selector.join(node_selector)
    add_offense(range, message: message(receiver, range)) do |corrector|
      first_range = receiver.source_range.end.join(node_selector)
      corrector.remove(first_range)
      corrector.replace(receiver_selector, 'pick')
    end
  end
end