Class: RuboCop::Cop::Rails::WhereExists

Inherits:
Base
  • Object
show all
Extended by:
AutoCorrector
Includes:
ConfigurableEnforcedStyle
Defined in:
lib/rubocop/cop/rails/where_exists.rb

Overview

Enforces consistent style when using exists?.

Two styles are supported for this cop. When EnforcedStyle is 'exists' then the cop enforces exists?(...) over where(...).exists?.

When EnforcedStyle is 'where' then the cop enforces where(...).exists? over exists?(...).

Examples:

EnforcedStyle: exists (default)

# bad
User.where(name: 'john').exists?
User.where(['name = ?', 'john']).exists?
User.where('name = ?', 'john').exists?
user.posts.where(published: true).exists?

# good
User.exists?(name: 'john')
User.where('length(name) > 10').exists?
user.posts.exists?(published: true)

EnforcedStyle: where

# bad
User.exists?(name: 'john')
User.exists?(['name = ?', 'john'])
user.posts.exists?(published: true)

# good
User.where(name: 'john').exists?
User.where(['name = ?', 'john']).exists?
User.where('name = ?', 'john').exists?
user.posts.where(published: true).exists?
User.where('length(name) > 10').exists?

Cop Safety Information:

  • This cop is unsafe for autocorrection because the behavior may change on the following case:

    [source,ruby]

    Author.includes(:articles).where(articles: id).exists?

    => Perform eager_load behavior (LEFT JOIN query) and get result.

    Author.includes(:articles).exists?(articles: id)

    => Perform preload behavior and ActiveRecord::StatementInvalid error occurs.

Constant Summary collapse

MSG = 
'Prefer `%<good_method>s` over `%<bad_method>s`.'
RESTRICT_ON_SEND = 
%i[exists?].freeze

Instance Method Summary collapse

Instance Method Details

#on_send(node) ⇒ Object Also known as: on_csend 



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# File 'lib/rubocop/cop/rails/where_exists.rb', line 65

def on_send(node)
  find_offenses(node) do |args|
    return unless convertable_args?(args)

    range = correction_range(node)
    good_method = build_good_method(args, dot: node.loc.dot)
    message = format(MSG, good_method: good_method, bad_method: range.source)

    add_offense(range, message: message) do |corrector|
      corrector.replace(range, good_method)
    end
  end
end