Send individual emails for each mail recipient (#26791).

We are creating multipe mails per class notification event, one per
recipient, wrapped in a Mailer::MultiMessage object to send them all at
once.

We keep the existing interface of all class methods intended to be used
by external code the same as they were before, with one exception:

We provide additional recipient addresses in options[:recipients] for
Mailer.security_notification. Since the first-class recipients have to
be users to render individual mails for them, additional recipient
addresses have to be provided with some other channel.

By providing additional recipients in options[:recipients], we can solve
the use-case for address change notifications for users, which probably
is the only real use-case for having to use a plain email address
instead of a User as a notification recipient.

Patch by Holger Just and Marius BALTEANU.

git-svn-id: http://svn.redmine.org/redmine/trunk@17583 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/email_address.rb

@@ -52,7 +52,7 @@ class EmailAddress < ActiveRecord::Base
     # in that case, the user is just being created and
     # should not receive this email.
     if user.mails != [address]
-      deliver_security_notification(user,
+      deliver_security_notification(
         message: :mail_body_security_notification_add,
         field: :field_mail,
         value: address
@@ -63,25 +63,26 @@ class EmailAddress < ActiveRecord::Base
   # send a security notification to user that an email has been changed (notified/not notified)
   def deliver_security_notification_update
     if saved_change_to_address?
-      recipients = [user, address_before_last_save]
       options = {
+        recipients: [address_before_last_save],
         message: :mail_body_security_notification_change_to,
         field: :field_mail,
         value: address
       }
     elsif saved_change_to_notify?
-      recipients = [user, address]
       options = {
+        recipients: [address],
         message: notify_before_last_save ? :mail_body_security_notification_notify_disabled : :mail_body_security_notification_notify_enabled,
         value: address
       }
     end
-    deliver_security_notification(recipients, options)
+    deliver_security_notification(options)
   end
 
   # send a security notification to user that an email address was deleted
   def deliver_security_notification_destroy
-    deliver_security_notification([user, address],
+    deliver_security_notification(
+      recipients: [address],
       message: :mail_body_security_notification_remove,
       field: :field_mail,
       value: address
@@ -89,8 +90,8 @@ class EmailAddress < ActiveRecord::Base
   end
 
   # generic method to send security notifications for email addresses
-  def deliver_security_notification(recipients, options={})
-    Mailer.security_notification(recipients,
+  def deliver_security_notification(options={})
+    Mailer.security_notification(user,
       options.merge(
         title: :label_my_account,
         url: {controller: 'my', action: 'account'}

app/models/mailer.rb

@@ -26,6 +26,113 @@ class Mailer < ActionMailer::Base
   include Redmine::I18n
   include Roadie::Rails::Automatic
 
+  # This class wraps multiple generated `Mail::Message` objects and allows to
+  # deliver them all at once. It is usually used to handle multiple mails for
+  # different receivers created by a single mail event. The wrapped mails can
+  # then be delivered in one go.
+  #
+  # The public interface of the class resembles a single mail message. You can
+  # directly use any of the deliver_* methods to send the contained messages
+  # now or later.
+  class MultiMessage
+    attr_reader :mails
+
+    # @param mails [Array<Mail, Proc>] an Array of mails or Procs which create
+    #   mail objects and allow to call a method on it.
+    def initialize(action, *args)
+      @action = action
+      @args = args
+
+      @mails = []
+    end
+
+    def for(users)
+      Array.wrap(users).each do |user|
+        @mails << ActionMailer::MessageDelivery.new(Mailer, @action, user, *@args)
+      end
+      self
+    end
+
+    def deliver_later(options = {})
+      enqueue_delivery :deliver_now, options
+    end
+
+    def deliver_later!(options = {})
+      enqueue_delivery :deliver_now!, options
+    end
+
+    def processed?
+      @mails.any?(&:processed?)
+    end
+
+    # @return [Object] the delivery method of the first mail.
+    #   Usually, this is the very same value for all mails and matches the
+    #   default value of the Mailer class
+    def delivery_method
+      (@mails.first || ActionMailer::Base::NullMail.new).delivery_method
+    end
+
+    # @return [ActionMailer::Base] the delivery handler of the first mail. This
+    #   is always the `Mailer` class.
+    def delivery_handler
+      (@mails.first || ActionMailer::Base::NullMail.new).delivery_handler
+    end
+
+    private
+
+    def method_missing(method, *args, &block)
+      if method =~ /\Adeliver([_!?]|\z)/
+        @mails.each do |mail|
+          mail.public_send(method, *args, &block)
+        end
+      else
+        super
+      end
+    end
+
+    def respond_to_missing(method, *args)
+      method =~ /\Adeliver([_!?]|\z)/ || method == 'processed?' || super
+    end
+
+    # This method is slightly adapted from ActionMailer::MessageDelivery
+    def enqueue_delivery(delivery_method, options = {})
+      if processed?
+        ::Kernel.raise "You've accessed the message before asking to " \
+          "deliver it later, so you may have made local changes that would " \
+          "be silently lost if we enqueued a job to deliver it. Why? Only " \
+          "the mailer method *arguments* are passed with the delivery job! " \
+          "Do not access the message in any way if you mean to deliver it " \
+          "later. Workarounds: 1. don't touch the message before calling " \
+          "#deliver_later, 2. only touch the message *within your mailer " \
+          "method*, or 3. use a custom Active Job instead of #deliver_later."
+      else
+        args = 'Mailer', @action.to_s, delivery_method.to_s, *@args
+        ::ActionMailer::DeliveryJob.set(options).perform_later(*args)
+      end
+    end
+  end
+
+  def process(action, *args)
+    user = args.shift
+    raise ArgumentError, "First argument has to be a user, was #{user.inspect}" unless user.is_a?(User)
+
+    initial_user = User.current
+    initial_language = ::I18n.locale
+    begin
+      User.current = user
+
+      lang = find_language(user.language) if user.logged?
+      lang ||= Setting.default_language
+      set_language_if_valid(lang)
+
+      super(action, *args)
+    ensure
+      User.current = initial_user
+      ::I18n.locale = initial_language
+    end
+  end
+
+
   def self.default_url_options
     options = {:protocol => Setting.protocol}
     if Setting.host_name.to_s =~ /\A(https?\:\/\/)?(.+?)(\:(\d+))?(\/.+)?\z/i
@@ -39,8 +146,11 @@ class Mailer < ActionMailer::Base
     options
   end
 
-  # Builds a mail for notifying to_users and cc_users about a new issue
-  def issue_add(issue, to_users, cc_users)
+  # Builds a mail for notifying the current user about a new issue
+  #
+  # Example:
+  #   issue_add(issue) => Mail::Message object
+  def issue_add(issue)
     redmine_headers 'Project' => issue.project.identifier,
                     'Issue-Id' => issue.id,
                     'Issue-Author' => issue.author.login
@@ -49,24 +159,34 @@ class Mailer < ActionMailer::Base
     references issue
     @author = issue.author
     @issue = issue
-    @users = to_users + cc_users
+    @users = [User.current]
     @issue_url = url_for(:controller => 'issues', :action => 'show', :id => issue)
-    mail :to => to_users,
-      :cc => cc_users,
+    mail :to => User.current,
       :subject => "[#{issue.project.name} - #{issue.tracker.name} ##{issue.id}] (#{issue.status.name}) #{issue.subject}"
   end
 
   # Notifies users about a new issue
-  def self.deliver_issue_add(issue)
-    to = issue.notified_users
-    cc = issue.notified_watchers - to
-    issue.each_notification(to + cc) do |users|
-      issue_add(issue, to & users, cc & users).deliver
-    end
+  #
+  # Example:
+  #   Mailer.issue_add(journal).deliver => sends emails to the project's recipients
+  def self.issue_add(issue)
+    users = issue.notified_users | issue.notified_watchers
+    MultiMessage.new(:issue_add, issue).for(users)
   end
 
-  # Builds a mail for notifying to_users and cc_users about an issue update
-  def issue_edit(journal, to_users, cc_users)
+  # Notifies users about a new issue
+  #
+  # Example:
+  #   Mailer.deliver_issue_add(issue) => sends emails to the project's recipients
+  def self.deliver_issue_add(issue)
+    issue_add(issue).deliver
+  end
+
+  # Builds a mail for notifying the current user about an issue update
+  #
+  # Example:
+  #   issue_edit(journal) => Mail::Message object
+  def issue_edit(journal)
     issue = journal.journalized
     redmine_headers 'Project' => issue.project.identifier,
                     'Issue-Id' => issue.id,
@@ -79,57 +199,88 @@ class Mailer < ActionMailer::Base
     s << "(#{issue.status.name}) " if journal.new_value_for('status_id')
     s << issue.subject
     @issue = issue
-    @users = to_users + cc_users
+    @users = [User.current]
     @journal = journal
-    @journal_details = journal.visible_details(@users.first)
+    @journal_details = journal.visible_details
     @issue_url = url_for(:controller => 'issues', :action => 'show', :id => issue, :anchor => "change-#{journal.id}")
-    mail :to => to_users,
-      :cc => cc_users,
+
+    mail :to => User.current,
       :subject => s
   end
 
-  # Notifies users about an issue update
-  def self.deliver_issue_edit(journal)
-    issue = journal.journalized.reload
-    to = journal.notified_users
-    cc = journal.notified_watchers - to
-    journal.each_notification(to + cc) do |users|
-      issue.each_notification(users) do |users2|
-        issue_edit(journal, to & users2, cc & users2).deliver
-      end
+  # Build a MultiMessage to notify users about an issue update
+  #
+  # Example:
+  #   Mailer.issue_edit(journal).deliver => sends emails to the project's recipients
+  def self.issue_edit(journal)
+    users  = journal.notified_users
+    users |= journal.notified_watchers
+    users.select! do |user|
+      journal.notes? || journal.visible_details(user).any?
     end
+    MultiMessage.new(:issue_edit, journal).for(users)
   end
 
-  def reminder(user, issues, days)
-    set_language_if_valid user.language
+  # Notifies users about an issue update
+  #
+  # Example:
+  #   Mailer.deliver_issue_edit(journal) => sends emails to the project's recipients
+  def self.deliver_issue_edit(journal)
+    issue_edit(journal).deliver
+  end
+
+  # Builds a Mail::Message object used to send en email reminder to the current
+  # user about their due issues.
+  #
+  # Example:
+  #   reminder(issues, days) => Mail::Message object
+  def reminder(issues, days)
     @issues = issues
     @days = days
     @issues_url = url_for(:controller => 'issues', :action => 'index',
-                                :set_filter => 1, :assigned_to_id => user.id,
+                                :set_filter => 1, :assigned_to_id => User.current.id,
                                 :sort => 'due_date:asc')
-    mail :to => user,
+    mail :to => User.current,
       :subject => l(:mail_subject_reminder, :count => issues.size, :days => days)
   end
 
-  # Builds a Mail::Message object used to email users belonging to the added document's project.
+  # Builds a Mail::Message object used to email the given user about their due
+  # issues
   #
   # Example:
-  #   document_added(document) => Mail::Message object
-  #   Mailer.document_added(document).deliver => sends an email to the document's project recipients
-  def document_added(document)
+  #   Mailer.reminder(user, issues, days, author).deliver => sends an email to the user
+  def self.reminder(user, issues, days)
+    MultiMessage.new(:reminder, issues, days).for(user)
+  end
+
+  # Builds a Mail::Message object used to email the current user that a document
+  # was added.
+  #
+  # Example:
+  #   document_added(document, author) => Mail::Message object
+  def document_added(document, author)
     redmine_headers 'Project' => document.project.identifier
-    @author = User.current
+    @author = author
     @document = document
     @document_url = url_for(:controller => 'documents', :action => 'show', :id => document)
-    mail :to => document.notified_users,
+    mail :to => User.current,
       :subject => "[#{document.project.name}] #{l(:label_document_new)}: #{document.title}"
   end
 
-  # Builds a Mail::Message object used to email recipients of a project when an attachements are added.
+  # Build a MultiMessage to notify users about an added document.
+  #
+  # Example:
+  #   Mailer.document_added(document).deliver => sends emails to the document's project recipients
+  def self.document_added(document)
+    users = document.notified_users
+    MultiMessage.new(:document_added, document, User.current).for(users)
+  end
+
+  # Builds a Mail::Message object used to email the current user when
+  # attachements are added.
   #
   # Example:
   #   attachments_added(attachments) => Mail::Message object
-  #   Mailer.attachments_added(attachments).deliver => sends an email to the project's recipients
   def attachments_added(attachments)
     container = attachments.first.container
     added_to = ''
@@ -139,29 +290,42 @@ class Mailer < ActionMailer::Base
     when 'Project'
       added_to_url = url_for(:controller => 'files', :action => 'index', :project_id => container)
       added_to = "#{l(:label_project)}: #{container}"
-      recipients = container.project.notified_users.select {|user| user.allowed_to?(:view_files, container.project)}
     when 'Version'
       added_to_url = url_for(:controller => 'files', :action => 'index', :project_id => container.project)
       added_to = "#{l(:label_version)}: #{container.name}"
-      recipients = container.project.notified_users.select {|user| user.allowed_to?(:view_files, container.project)}
     when 'Document'
       added_to_url = url_for(:controller => 'documents', :action => 'show', :id => container.id)
       added_to = "#{l(:label_document)}: #{container.title}"
-      recipients = container.notified_users
     end
     redmine_headers 'Project' => container.project.identifier
     @attachments = attachments
     @added_to = added_to
     @added_to_url = added_to_url
-    mail :to => recipients,
+    mail :to => User.current,
       :subject => "[#{container.project.name}] #{l(:label_attachment_new)}"
   end
 
-  # Builds a Mail::Message object used to email recipients of a news' project when a news item is added.
+  # Build a MultiMessage to notify users about an added attachment
+  #
+  # Example:
+  #   Mailer.attachments_added(attachments).deliver => sends emails to the project's recipients
+  def self.attachments_added(attachments)
+    container = attachments.first.container
+    case container.class.name
+    when 'Project', 'Version'
+      users = container.project.notified_users.select {|user| user.allowed_to?(:view_files, container.project)}
+    when 'Document'
+      users = container.notified_users
+    end
+
+    MultiMessage.new(:attachments_added, attachments).for(users)
+  end
+
+  # Builds a Mail::Message object used to email the current user when a news
+  # item is added.
   #
   # Example:
   #   news_added(news) => Mail::Message object
-  #   Mailer.news_added(news).deliver => sends an email to the news' project recipients
   def news_added(news)
     redmine_headers 'Project' => news.project.identifier
     @author = news.author
@@ -169,16 +333,24 @@ class Mailer < ActionMailer::Base
     references news
     @news = news
     @news_url = url_for(:controller => 'news', :action => 'show', :id => news)
-    mail :to => news.notified_users,
-      :cc => news.notified_watchers_for_added_news,
+    mail :to => User.current,
       :subject => "[#{news.project.name}] #{l(:label_news)}: #{news.title}"
   end
 
-  # Builds a Mail::Message object used to email recipients of a news' project when a news comment is added.
+  # Build a MultiMessage to notify users about a new news item
+  #
+  # Example:
+  #   Mailer.news_added(news).deliver => sends emails to the news' project recipients
+  def self.news_added(news)
+    users = news.notified_users | news.notified_watchers_for_added_news
+    MultiMessage.new(:news_added, news).for(users)
+  end
+
+  # Builds a Mail::Message object used to email the current user when a news
+  # comment is added.
   #
   # Example:
   #   news_comment_added(comment) => Mail::Message object
-  #   Mailer.news_comment_added(comment) => sends an email to the news' project recipients
   def news_comment_added(comment)
     news = comment.commented
     redmine_headers 'Project' => news.project.identifier
@@ -188,64 +360,87 @@ class Mailer < ActionMailer::Base
     @news = news
     @comment = comment
     @news_url = url_for(:controller => 'news', :action => 'show', :id => news)
-    mail :to => news.notified_users,
-     :cc => news.notified_watchers,
+    mail :to => User.current,
      :subject => "Re: [#{news.project.name}] #{l(:label_news)}: #{news.title}"
   end
 
-  # Builds a Mail::Message object used to email the recipients of the specified message that was posted.
+  # Build a MultiMessage to notify users about a new news comment
+  #
+  # Example:
+  #   Mailer.news_comment_added(comment).deliver => sends emails to the news' project recipients
+  def self.news_comment_added(comment)
+    news = comment.commented
+    users = news.notified_users | news.notified_watchers
+
+    MultiMessage.new(:news_comment_added, comment).for(users)
+  end
+
+  # Builds a Mail::Message object used to email the current user that the
+  # specified message was posted.
   #
   # Example:
   #   message_posted(message) => Mail::Message object
-  #   Mailer.message_posted(message).deliver => sends an email to the recipients
   def message_posted(message)
     redmine_headers 'Project' => message.project.identifier,
                     'Topic-Id' => (message.parent_id || message.id)
     @author = message.author
     message_id message
     references message.root
-    recipients = message.notified_users
-    cc = ((message.root.notified_watchers + message.board.notified_watchers).uniq - recipients)
     @message = message
     @message_url = url_for(message.event_url)
-    mail :to => recipients,
-      :cc => cc,
+    mail :to => User.current,
       :subject => "[#{message.board.project.name} - #{message.board.name} - msg#{message.root.id}] #{message.subject}"
   end
 
-  # Builds a Mail::Message object used to email the recipients of a project of the specified wiki content was added.
+  # Build a MultiMessage to notify users about a new forum message
+  #
+  # Example:
+  #   Mailer.message_posted(message).deliver => sends emails to the recipients
+  def self.message_posted(message)
+    users  = message.notified_users
+    users |= message.root.notified_watchers
+    users |= message.board.notified_watchers
+
+    MultiMessage.new(:message_posted, message).for(users)
+  end
+
+  # Builds a Mail::Message object used to email the current user that the
+  # specified wiki content was added.
   #
   # Example:
   #   wiki_content_added(wiki_content) => Mail::Message object
-  #   Mailer.wiki_content_added(wiki_content).deliver => sends an email to the project's recipients
   def wiki_content_added(wiki_content)
     redmine_headers 'Project' => wiki_content.project.identifier,
                     'Wiki-Page-Id' => wiki_content.page.id
     @author = wiki_content.author
     message_id wiki_content
-    recipients = wiki_content.notified_users
-    cc = wiki_content.page.wiki.notified_watchers - recipients
     @wiki_content = wiki_content
     @wiki_content_url = url_for(:controller => 'wiki', :action => 'show',
                                       :project_id => wiki_content.project,
                                       :id => wiki_content.page.title)
-    mail :to => recipients,
-      :cc => cc,
+    mail :to => User.current,
       :subject => "[#{wiki_content.project.name}] #{l(:mail_subject_wiki_content_added, :id => wiki_content.page.pretty_title)}"
   end
 
-  # Builds a Mail::Message object used to email the recipients of a project of the specified wiki content was updated.
+  # Build a MultiMessage to notify users about added wiki content
+  #
+  # Example:
+  #   Mailer.wiki_content_added(wiki_content).deliver => send emails to the project's recipients
+  def self.wiki_content_added(wiki_content)
+    users = wiki_content.notified_users | wiki_content.page.wiki.notified_watchers
+    MultiMessage.new(:wiki_content_added, wiki_content).for(users)
+  end
+
+  # Builds a Mail::Message object used to email the current user about an update
+  # of the specified wiki content.
   #
   # Example:
   #   wiki_content_updated(wiki_content) => Mail::Message object
-  #   Mailer.wiki_content_updated(wiki_content).deliver => sends an email to the project's recipients
   def wiki_content_updated(wiki_content)
     redmine_headers 'Project' => wiki_content.project.identifier,
                     'Wiki-Page-Id' => wiki_content.page.id
     @author = wiki_content.author
     message_id wiki_content
-    recipients = wiki_content.notified_users
-    cc = wiki_content.page.wiki.notified_watchers + wiki_content.page.notified_watchers - recipients
     @wiki_content = wiki_content
     @wiki_content_url = url_for(:controller => 'wiki', :action => 'show',
                                       :project_id => wiki_content.project,
@@ -253,56 +448,92 @@ class Mailer < ActionMailer::Base
     @wiki_diff_url = url_for(:controller => 'wiki', :action => 'diff',
                                    :project_id => wiki_content.project, :id => wiki_content.page.title,
                                    :version => wiki_content.version)
-    mail :to => recipients,
-      :cc => cc,
+    mail :to => User.current,
       :subject => "[#{wiki_content.project.name}] #{l(:mail_subject_wiki_content_updated, :id => wiki_content.page.pretty_title)}"
   end
 
-  # Builds a Mail::Message object used to email the specified user their account information.
+  # Build a MultiMessage to notify users about the update of the specified wiki content
   #
   # Example:
-  #   account_information(user, password) => Mail::Message object
-  #   Mailer.account_information(user, password).deliver => sends account information to the user
-  def account_information(user, password)
-    set_language_if_valid user.language
-    @user = user
+  #   Mailer.wiki_content_updated(wiki_content).deliver => sends an email to the project's recipients
+  def self.wiki_content_updated(wiki_content)
+    users  = wiki_content.notified_users
+    users |= wiki_content.page.notified_watchers
+    users |= wiki_content.page.wiki.notified_watchers
+
+    MultiMessage.new(:wiki_content_updated, wiki_content).for(users)
+  end
+
+  # Builds a Mail::Message object used to email the current user their account information.
+  #
+  # Example:
+  #   account_information(password) => Mail::Message object
+  def account_information(password)
+    @user = User.current
     @password = password
     @login_url = url_for(:controller => 'account', :action => 'login')
-    mail :to => user.mail,
+    mail :to => User.current.mail,
       :subject => l(:mail_subject_register, Setting.app_title)
   end
 
-  # Builds a Mail::Message object used to email all active administrators of an account activation request.
+  # Build a MultiMessage to mail a user their account information
+  #
+  # Example:
+  #   Mailer.account_information(user, password).deliver => sends account information to the user
+  def self.account_information(user, password)
+    MultiMessage.new(:account_information, password).for(user)
+  end
+
+  # Builds a Mail::Message object used to email the current user about an account activation request.
   #
   # Example:
   #   account_activation_request(user) => Mail::Message object
-  #   Mailer.account_activation_request(user).deliver => sends an email to all active administrators
   def account_activation_request(user)
-    # Send the email to all active administrators
-    recipients = User.active.where(:admin => true)
     @user = user
     @url = url_for(:controller => 'users', :action => 'index',
                          :status => User::STATUS_REGISTERED,
                          :sort_key => 'created_on', :sort_order => 'desc')
-    mail :to => recipients,
+    mail :to => User.current,
       :subject => l(:mail_subject_account_activation_request, Setting.app_title)
   end
 
-  # Builds a Mail::Message object used to email the specified user that their account was activated by an administrator.
+  # Build a MultiMessage to email all active administrators of an account activation request.
   #
   # Example:
-  #   account_activated(user) => Mail::Message object
-  #   Mailer.account_activated(user).deliver => sends an email to the registered user
-  def account_activated(user)
-    set_language_if_valid user.language
-    @user = user
+  #   Mailer.account_activation_request(user).deliver => sends an email to all active administrators
+  def self.account_activation_request(user)
+    # Send the email to all active administrators
+    users = User.active.where(:admin => true)
+    MultiMessage.new(:account_activation_request, user).for(users)
+  end
+
+  # Builds a Mail::Message object used to email the account of the current user
+  # was activated by an administrator.
+  #
+  # Example:
+  #   account_activated => Mail::Message object
+  def account_activated
+    @user = User.current
     @login_url = url_for(:controller => 'account', :action => 'login')
-    mail :to => user.mail,
+    mail :to => User.current.mail,
       :subject => l(:mail_subject_register, Setting.app_title)
   end
 
+  # Build a MultiMessage to email the specified user that their account was
+  # activated by an administrator.
+  #
+  # Example:
+  #   Mailer.account_activated(user).deliver => sends an email to the registered user
+  def self.account_activated(user)
+    MultiMessage.new(:account_activated).for(user)
+  end
+
+  # Builds a Mail::Message object used to email the lost password token to the
+  # token's user (or a different recipient).
+  #
+  # Example:
+  #   lost_password(token) => Mail::Message object
   def lost_password(token, recipient=nil)
-    set_language_if_valid(token.user.language)
     recipient ||= token.user.mail
     @token = token
     @url = url_for(:controller => 'account', :action => 'lost_password', :token => token.value)
@@ -310,6 +541,15 @@ class Mailer < ActionMailer::Base
       :subject => l(:mail_subject_lost_password, Setting.app_title)
   end
 
+  # Build a MultiMessage to email the token's user (or a different recipient)
+  # the lost password token for the token's user.
+  #
+  # Example:
+  #   Mailer.lost_password(token).deliver => sends an email to the user
+  def self.lost_password(token, recipient=nil)
+    MultiMessage.new(:lost_password, token, recipient).for(token.user)
+  end
+
   # Notifies user that his password was updated
   def self.password_updated(user, options={})
     # Don't send a notification to the dummy email address when changing the password
@@ -326,39 +566,92 @@ class Mailer < ActionMailer::Base
     ).deliver
   end
 
+  # Builds a Mail::Message object used to email the user activation link to the
+  # token's user.
+  #
+  # Example:
+  #   register(token) => Mail::Message object
   def register(token)
-    set_language_if_valid(token.user.language)
     @token = token
     @url = url_for(:controller => 'account', :action => 'activate', :token => token.value)
     mail :to => token.user.mail,
       :subject => l(:mail_subject_register, Setting.app_title)
   end
 
-  def security_notification(recipients, options={})
-    @user = Array(recipients).detect{|r| r.is_a? User }
-    set_language_if_valid(@user.try :language)
+  # Build a MultiMessage to email the user activation link to the token's user.
+  #
+  # Example:
+  #   Mailer.register(token).deliver => sends an email to the token's user
+  def self.register(token)
+    MultiMessage.new(:register, token).for(token.user)
+  end
+
+  # Build a Mail::Message object to email the current user and the additional
+  # recipients given in options[:recipients] about a security related event.
+  #
+  # Example:
+  #   security_notification(users,
+  #     message: :mail_body_security_notification_add,
+  #     field: :field_mail,
+  #     value: address
+  #   ) => Mail::Message object
+  def security_notification(sender, options={})
+    @sender = sender
+    redmine_headers 'Sender' => sender.login
     @message = l(options[:message],
       field: (options[:field] && l(options[:field])),
       value: options[:value]
     )
     @title = options[:title] && l(options[:title])
-    @originator = options[:originator] || User.current
+    @originator = options[:originator] || sender
     @remote_ip = options[:remote_ip] || @originator.remote_ip
     @url = options[:url] && (options[:url].is_a?(Hash) ? url_for(options[:url]) : options[:url])
     redmine_headers 'Sender' => @originator.login
     redmine_headers 'Url' => @url
-    mail :to => recipients,
+    mail :to => [User.current, *options[:recipients]].uniq,
       :subject => "[#{Setting.app_title}] #{l(:mail_subject_security_notification)}"
   end
 
-  def settings_updated(recipients, changes)
-    redmine_headers 'Sender' => User.current.login
+  # Build a MultiMessage to email the given users about a security related event.
+  #
+  # You can specify additional recipients in options[:recipients]. These will be
+  # added to all generated mails for all given users. Usually, you'll want to
+  # give only a single user when setting the additional recipients.
+  #
+  # Example:
+  #   Mailer.security_notification(users,
+  #     message: :mail_body_security_notification_add,
+  #     field: :field_mail,
+  #     value: address
+  #   ).deliver => sends a security notification to the given user(s)
+  def self.security_notification(users, options={})
+    sender = User.current
+    MultiMessage.new(:security_notification, sender, options).for(users)
+  end
+
+  # Build a Mail::Message object to email the current user about an updated
+  # setting.
+  #
+  # Example:
+  #   settings_updated(sender, [:host_name]) => Mail::Message object
+  def settings_updated(sender, changes)
+    @sender = sender
+    redmine_headers 'Sender' => sender.login
     @changes = changes
     @url = url_for(controller: 'settings', action: 'index')
-    mail :to => recipients,
+    mail :to => User.current,
       :subject => "[#{Setting.app_title}] #{l(:mail_subject_security_notification)}"
   end
 
+  # Build a MultiMessage to email the given users about an update of a setting.
+  #
+  # Example:
+  #   Mailer.settings_updated(users, [:host_name]).deliver => sends emails to the given user(s) about the update
+  def self.settings_updated(users, changes)
+    sender = User.current
+    MultiMessage.new(:settings_updated, sender, changes).for(users)
+  end
+  
   # Notifies admins about settings changes
   def self.security_settings_updated(changes)
     return unless changes.present?
@@ -367,13 +660,24 @@ class Mailer < ActionMailer::Base
     settings_updated(users, changes).deliver
   end
 
-  def test_email(user)
-    set_language_if_valid(user.language)
+  # Build a Mail::Message object with a test email for the current user
+  #
+  # Example:
+  #   test_email => Mail::Message object
+  def test_email
     @url = url_for(:controller => 'welcome')
-    mail :to => user.mail,
+    mail :to => User.current.mail,
       :subject => 'Redmine test'
   end
 
+  # Build a MultiMessage to send a test email the given user
+  #
+  # Example:
+  #   Mailer.test_email(user).deliver => send an email to the given user
+  def self.test_email(user)
+    MultiMessage.new(:test_email).for(user)
+  end
+
   # Sends reminders to issue assignees
   # Available options:
   # * :days     => how many days in the future to remind about (defaults to 7)
@@ -483,7 +787,7 @@ class Mailer < ActionMailer::Base
       headers[:references] = @references_objects.collect {|o| "<#{self.class.references_for(o)}>"}.join(' ')
     end
 
-    m = if block_given?
+    if block_given?
       super headers, &block
     else
       super headers do |format|
@@ -491,15 +795,6 @@ class Mailer < ActionMailer::Base
         format.html unless Setting.plain_text_mail?
       end
     end
-    set_language_if_valid @initial_language
-
-    m
-  end
-
-  def initialize(*args)
-    @initial_language = current_language
-    set_language_if_valid Setting.default_language
-    super
   end
 
   def self.deliver_mail(mail)
@@ -521,6 +816,8 @@ class Mailer < ActionMailer::Base
     if m = method.to_s.match(%r{^deliver_(.+)$})
       ActiveSupport::Deprecation.warn "Mailer.deliver_#{m[1]}(*args) is deprecated. Use Mailer.#{m[1]}(*args).deliver instead."
       send(m[1], *args).deliver
+    elsif action_methods.include?(method.to_s)
+      MultiMessage.new(method, *args).for(User.current)
     else
       super
     end

app/views/mailer/security_notification.html.erb

@@ -9,5 +9,4 @@
 
 <p><%= l(:field_user) %>: <strong><%= @originator.login %></strong><br/>
 <%= l(:field_remote_ip) %>: <strong><%= @remote_ip %></strong><br/>
-<%= l(:label_date) %>: <strong><%= format_time Time.now, true, @user %></strong></p>
-
+<%= l(:label_date) %>: <strong><%= format_time Time.now, true %></strong></p>

app/views/mailer/security_notification.text.erb

@@ -4,5 +4,4 @@
 
 <%= l(:field_user) %>: <%= @originator.login %>
 <%= l(:field_remote_ip) %>: <%= @remote_ip %>
-<%= l(:label_date) %>: <%= format_time Time.now, true, @user %>
-
+<%= l(:label_date) %>: <%= format_time Time.now, true %>

app/views/mailer/settings_updated.html.erb

@@ -8,7 +8,7 @@
 
 <%= link_to @url, @url %>
 
-<p><%= l(:field_user) %>: <strong><%= User.current.login %></strong><br/>
-<%= l(:field_remote_ip) %>: <strong><%= User.current.remote_ip %></strong><br/>
+<p><%= l(:field_user) %>: <strong><%= @sender.login %></strong><br/>
+<%= l(:field_remote_ip) %>: <strong><%= @sender.remote_ip %></strong><br/>
 <%= l(:label_date) %>: <strong><%= format_time Time.now, true %></strong></p>
 

app/views/mailer/settings_updated.text.erb

@@ -6,7 +6,7 @@
 
 <%= @url %>
 
-<%= l(:field_user) %>: <%= User.current.login %>
-<%= l(:field_remote_ip) %>: <%= User.current.remote_ip %>
+<%= l(:field_user) %>: <%= @sender.login %>
+<%= l(:field_remote_ip) %>: <%= @sender.remote_ip %>
 <%= l(:label_date) %>: <%= format_time Time.now, true %>
 

test/functional/documents_controller_test.rb

@@ -132,7 +132,7 @@ LOREM
     assert_equal Enumeration.find(2), document.category
     assert_equal 1, document.attachments.size
     assert_equal 'testfile.txt', document.attachments.first.filename
-    assert_equal 1, ActionMailer::Base.deliveries.size
+    assert_equal 2, ActionMailer::Base.deliveries.size
   end
 
   def test_create_with_failure

test/functional/issues_controller_test.rb

@@ -3483,7 +3483,7 @@ class IssuesControllerTest < Redmine::ControllerTest
       end
       assert_redirected_to :controller => 'issues', :action => 'show', :id => Issue.last.id
 
-      assert_equal 1, ActionMailer::Base.deliveries.size
+      assert_equal 2, ActionMailer::Base.deliveries.size
     end
   end
 
@@ -5103,7 +5103,7 @@ class IssuesControllerTest < Redmine::ControllerTest
 
           }
         }
-      assert_equal 1, ActionMailer::Base.deliveries.size
+      assert_equal 2, ActionMailer::Base.deliveries.size
     end
   end
 
@@ -5585,7 +5585,7 @@ class IssuesControllerTest < Redmine::ControllerTest
     assert_not_equal "Bulk should fail", Journal.last.notes
   end
 
-  def test_bullk_update_should_send_a_notification
+  def test_bulk_update_should_send_a_notification
     @request.session[:user_id] = 2
     ActionMailer::Base.deliveries.clear
     with_settings :notified_events => %w(issue_updated) do
@@ -5599,7 +5599,7 @@ class IssuesControllerTest < Redmine::ControllerTest
           }
         }
       assert_response 302
-      assert_equal 2, ActionMailer::Base.deliveries.size
+      assert_equal 5, ActionMailer::Base.deliveries.size
     end
   end
 

test/functional/issues_custom_fields_visibility_test.rb

@@ -285,7 +285,8 @@ class IssuesCustomFieldsVisibilityTest < Redmine::ControllerTest
         assert_response 302
       end
     end
-    assert_equal users_to_test.values.uniq.size, ActionMailer::Base.deliveries.size
+
+    assert_equal users_to_test.keys.size, ActionMailer::Base.deliveries.size
     # tests that each user receives 1 email with the custom fields he is allowed to see only
     users_to_test.each do |user, fields|
       mails = ActionMailer::Base.deliveries.select {|m| m.bcc.include? user.mail}
@@ -322,7 +323,7 @@ class IssuesCustomFieldsVisibilityTest < Redmine::ControllerTest
         }
       assert_response 302
     end
-    assert_equal users_to_test.values.uniq.size, ActionMailer::Base.deliveries.size
+    assert_equal users_to_test.keys.size, ActionMailer::Base.deliveries.size
     # tests that each user receives 1 email with the custom fields he is allowed to see only
     users_to_test.each do |user, fields|
       mails = ActionMailer::Base.deliveries.select {|m| m.bcc.include? user.mail}

test/functional/messages_controller_test.rb

@@ -136,14 +136,17 @@ class MessagesControllerTest < Redmine::ControllerTest
     assert_equal 2, message.author_id
     assert_equal 1, message.board_id
 
-    mail = ActionMailer::Base.deliveries.last
-    assert_not_nil mail
+    mails = ActionMailer::Base.deliveries
+    assert_not_empty mails
+    mails.each do |mail|
       assert_equal "[#{message.board.project.name} - #{message.board.name} - msg#{message.root.id}] Test created message", mail.subject
       assert_mail_body_match 'Message body', mail
+    end
+
     # author
-    assert mail.bcc.include?('jsmith@somenet.foo')
+    assert_equal ['jsmith@somenet.foo'], mails[0].bcc
     # project member
-    assert mail.bcc.include?('dlopper@somenet.foo')
+    assert_equal ['dlopper@somenet.foo'], mails[1].bcc
   end
 
   def test_get_edit

test/functional/news_controller_test.rb

@@ -127,7 +127,7 @@ class NewsControllerTest < Redmine::ControllerTest
     assert_equal 'This is the description', news.description
     assert_equal User.find(2), news.author
     assert_equal Project.find(1), news.project
-    assert_equal 1, ActionMailer::Base.deliveries.size
+    assert_equal 2, ActionMailer::Base.deliveries.size
   end
 
   def test_post_create_with_attachment

test/unit/changeset_test.rb

@@ -46,7 +46,7 @@ class ChangesetTest < ActiveSupport::TestCase
     fixed = Issue.find(1)
     assert fixed.closed?
     assert_equal 90, fixed.done_ratio
-    assert_equal 1, ActionMailer::Base.deliveries.size
+    assert_equal 2, ActionMailer::Base.deliveries.size
   end
 
   def test_ref_keywords

test/unit/comment_test.rb

@@ -36,7 +36,7 @@ class CommentTest < ActiveSupport::TestCase
     Watcher.create!(:watchable => @news, :user => @jsmith)
 
     with_settings :notified_events => %w(news_comment_added) do
-      assert_difference 'ActionMailer::Base.deliveries.size' do
+      assert_difference 'ActionMailer::Base.deliveries.size', 2 do
         Comment.create!(:commented => @news, :author => @jsmith, :comments => "my comment")
       end
     end

test/unit/document_test.rb

@@ -41,7 +41,7 @@ class DocumentTest < ActiveSupport::TestCase
       doc = Document.new(:project => Project.find(1), :title => 'New document', :category => Enumeration.find_by_name('User documentation'))
       assert doc.save
     end
-    assert_equal 1, ActionMailer::Base.deliveries.size
+    assert_equal 2, ActionMailer::Base.deliveries.size
   end
 
   def test_create_with_default_category

test/unit/issue_test.rb

@@ -2529,7 +2529,7 @@ class IssueTest < ActiveSupport::TestCase
                       :subject => 'test_create', :estimated_hours => '1:30')
     with_settings :notified_events => %w(issue_added) do
       assert issue.save
-      assert_equal 1, ActionMailer::Base.deliveries.size
+      assert_equal 2, ActionMailer::Base.deliveries.size
     end
   end
 
@@ -2541,7 +2541,7 @@ class IssueTest < ActiveSupport::TestCase
                       :subject => 'test_create', :estimated_hours => '1:30')
     with_settings :notified_events => %w(issue_added issue_updated) do
       assert issue.save
-      assert_equal 1, ActionMailer::Base.deliveries.size
+      assert_equal 2, ActionMailer::Base.deliveries.size
     end
   end
 
@@ -2568,7 +2568,8 @@ class IssueTest < ActiveSupport::TestCase
       issue.init_journal User.find(1)
       issue.assigned_to = nil
       issue.save!
-      assert_include user.mail, ActionMailer::Base.deliveries.last.bcc
+
+      assert_include [user.mail], ActionMailer::Base.deliveries.map(&:bcc)
     end
   end
 
@@ -2581,7 +2582,7 @@ class IssueTest < ActiveSupport::TestCase
     issue.subject = 'Subjet update'
     with_settings :notified_events => %w(issue_updated) do
       assert issue.save
-      assert_equal 1, ActionMailer::Base.deliveries.size
+      assert_equal 2, ActionMailer::Base.deliveries.size
       ActionMailer::Base.deliveries.clear
 
       stale.init_journal(User.find(1))

test/unit/journal_observer_test.rb

@@ -36,7 +36,7 @@ class JournalObserverTest < ActiveSupport::TestCase
     with_settings :notified_events => %w(issue_updated) do
       assert journal.save
     end
-    assert_equal 1, ActionMailer::Base.deliveries.size
+    assert_equal 2, ActionMailer::Base.deliveries.size
   end
 
   def test_create_should_not_send_email_notification_with_notify_set_to_false
@@ -71,7 +71,7 @@ class JournalObserverTest < ActiveSupport::TestCase
     with_settings :notified_events => %w(issue_note_added) do
       assert journal.save
     end
-    assert_equal 1, ActionMailer::Base.deliveries.size
+    assert_equal 2, ActionMailer::Base.deliveries.size
   end
 
   def test_create_should_not_send_email_notification_without_issue_note_added
@@ -95,7 +95,7 @@ class JournalObserverTest < ActiveSupport::TestCase
     with_settings :notified_events => %w(issue_status_updated) do
       assert issue.save
     end
-    assert_equal 1, ActionMailer::Base.deliveries.size
+    assert_equal 2, ActionMailer::Base.deliveries.size
   end
 
   def test_create_should_not_send_email_notification_without_issue_status_updated
@@ -132,7 +132,7 @@ class JournalObserverTest < ActiveSupport::TestCase
     with_settings :notified_events => %w(issue_assigned_to_updated) do
       assert issue.save
     end
-    assert_equal 1, ActionMailer::Base.deliveries.size
+    assert_equal 2, ActionMailer::Base.deliveries.size
   end
 
   def test_create_should_not_send_email_notification_without_issue_assignee_updated
@@ -157,7 +157,7 @@ class JournalObserverTest < ActiveSupport::TestCase
     with_settings :notified_events => %w(issue_priority_updated) do
       assert issue.save
     end
-    assert_equal 1, ActionMailer::Base.deliveries.size
+    assert_equal 2, ActionMailer::Base.deliveries.size
   end
 
   def test_create_should_not_send_email_notification_without_issue_priority_updated

test/unit/journal_test.rb

@@ -50,7 +50,7 @@ class JournalTest < ActiveSupport::TestCase
     journal = issue.init_journal(user, issue)
 
     assert journal.save
-    assert_equal 1, ActionMailer::Base.deliveries.size
+    assert_equal 2, ActionMailer::Base.deliveries.size
   end
 
   def test_should_not_save_journal_with_blank_notes_and_no_details

test/unit/mail_handler_test.rb

@@ -440,11 +440,12 @@ class MailHandlerTest < ActiveSupport::TestCase
       )
     end
 
-    # only 1 email for the new issue notification
-    assert_equal 1, ActionMailer::Base.deliveries.size
-    email = ActionMailer::Base.deliveries.first
+    # only 2 emails for the new issue notification
+    assert_equal 2, ActionMailer::Base.deliveries.size
+    ActionMailer::Base.deliveries.each do |email|
       assert_include 'Ticket by unknown user', email.subject
     end
+  end
 
   def test_created_user_should_have_mail_notification_to_none_with_no_notification_option
     assert_difference 'User.count' do
@@ -877,7 +878,7 @@ class MailHandlerTest < ActiveSupport::TestCase
   def test_update_issue_should_send_email_notification
     journal = submit_email('ticket_reply.eml')
     assert journal.is_a?(Journal)
-    assert_equal 1, ActionMailer::Base.deliveries.size
+    assert_equal 3, ActionMailer::Base.deliveries.size
   end
 
   def test_update_issue_should_not_set_defaults

test/unit/mailer_test.rb

@@ -412,11 +412,15 @@ class MailerTest < ActiveSupport::TestCase
     journal.save!
 
     Role.find(2).add_permission! :view_private_notes
+    assert_difference 'ActionMailer::Base.deliveries.size', 2 do
       Mailer.deliver_issue_edit(journal)
-    assert_equal %w(dlopper@somenet.foo jsmith@somenet.foo), ActionMailer::Base.deliveries.last.bcc.sort
+    end
+    assert_equal %w(dlopper@somenet.foo jsmith@somenet.foo), ActionMailer::Base.deliveries.last(2).flat_map(&:bcc).sort
 
     Role.find(2).remove_permission! :view_private_notes
+    assert_difference 'ActionMailer::Base.deliveries.size', 1 do
       Mailer.deliver_issue_edit(journal)
+    end
     assert_equal %w(jsmith@somenet.foo), ActionMailer::Base.deliveries.last.bcc.sort
   end
 
@@ -534,7 +538,7 @@ class MailerTest < ActiveSupport::TestCase
   def test_wiki_content_added
     content = WikiContent.find(1)
     with_each_language_as_default do
-      assert_difference 'ActionMailer::Base.deliveries.size' do
+      assert_difference 'ActionMailer::Base.deliveries.size', 2 do
         assert Mailer.wiki_content_added(content).deliver
         assert_select_email do
           assert_select 'a[href=?]',
@@ -548,7 +552,7 @@ class MailerTest < ActiveSupport::TestCase
   def test_wiki_content_updated
     content = WikiContent.find(1)
     with_each_language_as_default do
-      assert_difference 'ActionMailer::Base.deliveries.size' do
+      assert_difference 'ActionMailer::Base.deliveries.size', 2 do
         assert Mailer.wiki_content_updated(content).deliver
         assert_select_email do
           assert_select 'a[href=?]',

test/unit/news_test.rb

@@ -34,7 +34,7 @@ class NewsTest < ActiveSupport::TestCase
     with_settings :notified_events => %w(news_added) do
       assert news.save
     end
-    assert_equal 1, ActionMailer::Base.deliveries.size
+    assert_equal 2, ActionMailer::Base.deliveries.size
   end
 
   def test_should_include_news_for_projects_with_news_enabled

test/unit/repository_test.rb

@@ -262,14 +262,15 @@ class RepositoryTest < ActiveSupport::TestCase
     assert_equal User.find_by_login('dlopper'), journal.user
     assert_equal 'Applied in changeset r2.', journal.notes
 
-    # 2 email notifications
-    assert_equal 2, ActionMailer::Base.deliveries.size
-    mail = ActionMailer::Base.deliveries.first
+    # 5 email notifications, 2 for #1, 3 for #2
+    assert_equal 5, ActionMailer::Base.deliveries.size
+    ActionMailer::Base.deliveries.first(2).each do |mail|
       assert_not_nil mail
       assert mail.subject.starts_with?(
           "[#{fixed_issue.project.name} - #{fixed_issue.tracker.name} ##{fixed_issue.id}]")
       assert_mail_body_match(
           "Status changed from #{old_status} to #{fixed_issue.status}", mail)
+    end
 
     # ignoring commits referencing an issue of another project
     assert_equal [], Issue.find(4).changesets

test/unit/wiki_content_test.rb

@@ -53,8 +53,10 @@ class WikiContentTest < ActiveSupport::TestCase
       assert page.save
     end
 
-    assert_equal 1, ActionMailer::Base.deliveries.size
-    assert_include 'wiki page has been added', mail_body(ActionMailer::Base.deliveries.last)
+    assert_equal 2, ActionMailer::Base.deliveries.size
+    ActionMailer::Base.deliveries.each do |mail|
+      assert_include 'wiki page has been added', mail_body(mail)
+    end
   end
 
   def test_update_should_be_versioned
@@ -100,8 +102,10 @@ class WikiContentTest < ActiveSupport::TestCase
       assert content.save
     end
 
-    assert_equal 1, ActionMailer::Base.deliveries.size
-    assert_include 'wiki page has been updated', mail_body(ActionMailer::Base.deliveries.last)
+    assert_equal 2, ActionMailer::Base.deliveries.size
+    ActionMailer::Base.deliveries.each do |mail|
+      assert_include 'wiki page has been updated', mail_body(mail)
+    end
   end
 
   def test_fetch_history