Enable Style/Proc cop for rubocop

.rubocop.yml

@@ -533,6 +533,10 @@ Style/WhileUntilModifier:
 Style/WordArray:
   Enabled: true
 
+# Use `proc` instead of `Proc.new`.
+Style/Proc:
+  Enabled: true
+
 # Metrics #####################################################################
 
 # A calculated magnitude based on number of assignments,

.rubocop_todo.yml

@@ -226,11 +226,6 @@ Style/PredicateName:
 Style/PreferredHashMethods:
   Enabled: false
 
-# Offense count: 8
-# Cop supports --auto-correct.
-Style/Proc:
-  Enabled: false
-
 # Offense count: 62
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle, SupportedStyles.

app/mailers/base_mailer.rb

@@ -5,8 +5,8 @@ class BaseMailer < ActionMailer::Base
   attr_accessor :current_user
   helper_method :current_user, :can?
 
-  default from:     Proc.new { default_sender_address.format }
-  default reply_to: Proc.new { default_reply_to_address.format }
+  default from:     proc { default_sender_address.format }
+  default reply_to: proc { default_reply_to_address.format }
 
   def can?
     Ability.allowed?(current_user, action, subject)

app/models/milestone.rb

@@ -30,7 +30,7 @@ class Milestone < ActiveRecord::Base
 
   validates :title, presence: true, uniqueness: { scope: :project_id }
   validates :project, presence: true
-  validate :start_date_should_be_less_than_due_date, if: Proc.new { |m| m.start_date.present? && m.due_date.present? }
+  validate :start_date_should_be_less_than_due_date, if: proc { |m| m.start_date.present? && m.due_date.present? }
 
   strip_attributes :title
 

app/models/service.rb

@@ -25,7 +25,7 @@ class Service < ActiveRecord::Base
   belongs_to :project, inverse_of: :services
   has_one :service_hook
 
-  validates :project_id, presence: true, unless: Proc.new { |service| service.template? }
+  validates :project_id, presence: true, unless: proc { |service| service.template? }
 
   scope :visible, -> { where.not(type: 'GitlabIssueTrackerService') }
   scope :issue_trackers, -> { where(category: 'issue_tracker') }

changelogs/unreleased/style-proc-cop.yml

@@ -0,0 +1,4 @@
+---
+title: Enable Style/Proc cop for rubocop
+merge_request:
+author: mhasbini

lib/api/api_guard.rb

@@ -121,7 +121,7 @@ module API
       end
 
       def oauth2_bearer_token_error_handler
-        Proc.new do |e|
+        proc do |e|
           response =
             case e
             when MissingTokenError

lib/gitlab/ldap/config.rb

@@ -124,9 +124,9 @@ module Gitlab
 
       def name_proc
         if allow_username_or_email_login
-          Proc.new { |name| name.gsub(/@.*\z/, '') }
+          proc { |name| name.gsub(/@.*\z/, '') }
         else
-          Proc.new { |name| name }
+          proc { |name| name }
         end
       end
 

spec/initializers/trusted_proxies_spec.rb

@@ -56,7 +56,7 @@ describe 'trusted_proxies', lib: true do
   end
 
   def stub_request(headers = {})
-    ActionDispatch::RemoteIp.new(Proc.new { }, false, Rails.application.config.action_dispatch.trusted_proxies).call(headers)
+    ActionDispatch::RemoteIp.new(proc { }, false, Rails.application.config.action_dispatch.trusted_proxies).call(headers)
     ActionDispatch::Request.new(headers)
   end