Optimize watchers list rendering by eager loading email addresses (#42589).

Patch by Go MAEDA (user:maeda).


git-svn-id: https://svn.redmine.org/redmine/trunk@23722 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/helpers/watchers_helper.rb

@@ -48,7 +48,9 @@ module WatchersHelper
   def watchers_list(object)
     remove_allowed = User.current.allowed_to?(:"delete_#{object.class.name.underscore}_watchers", object.project)
     content = ''.html_safe
-    lis = object.watcher_users.sorted.collect do |user|
+    scope = object.watcher_users
+    scope = scope.includes(:email_address) if Setting.gravatar_enabled?
+    lis = scope.sorted.collect do |user|
       s = ''.html_safe
       s << avatar(user, :size => "16").to_s if user.is_a?(User)
       s << link_to_principal(user, class: user.class.to_s.downcase)

app/models/principal.rb

@@ -35,6 +35,8 @@ class Principal < ApplicationRecord
            :foreign_key => 'user_id'
   has_many :projects, :through => :memberships
   has_many :issue_categories, :foreign_key => 'assigned_to_id', :dependent => :nullify
+  # Always returns nil for groups
+  has_one :email_address, lambda {where :is_default => true}, :autosave => true, :foreign_key => 'user_id'
 
   validate :validate_status
 

app/models/user.rb

@@ -91,7 +91,6 @@ class User < Principal
   has_one :preference, :dependent => :destroy, :class_name => 'UserPreference'
   has_one :atom_token, lambda {where "#{table.name}.action='feeds'"}, :class_name => 'Token'
   has_one :api_token, lambda {where "#{table.name}.action='api'"}, :class_name => 'Token'
-  has_one :email_address, lambda {where :is_default => true}, :autosave => true
   has_many :email_addresses, :dependent => :delete_all
   belongs_to :auth_source