Add email for milestone change

16 files changed, 139 insertions, 2 deletions

diff --git a/app/mailers/emails/issues.rb b/app/mailers/emails/issues.rb
index 602e5afe26b..93b51fb1774 100644
--- a/app/mailers/emails/issues.rb
+++ b/app/mailers/emails/issues.rb
@@ -45,6 +45,20 @@ module Emails
       mail_answer_thread(@issue, issue_thread_options(updated_by_user_id, recipient_id, reason))
     end
 
+    def removed_milestone_issue_email(recipient_id, issue_id, updated_by_user_id, reason = nil)
+      setup_issue_mail(issue_id, recipient_id)
+
+      mail_answer_thread(@issue, issue_thread_options(updated_by_user_id, recipient_id, reason))
+    end
+
+    def changed_milestone_issue_email(recipient_id, issue_id, milestone, updated_by_user_id, reason = nil)
+      setup_issue_mail(issue_id, recipient_id)
+
+      @milestone = milestone
+      @milestone_url = milestone_url(@milestone)
+      mail_answer_thread(@issue, issue_thread_options(updated_by_user_id, recipient_id, reason))
+    end
+
     def issue_status_changed_email(recipient_id, issue_id, status, updated_by_user_id, reason = nil)
       setup_issue_mail(issue_id, recipient_id)
 
diff --git a/app/mailers/emails/merge_requests.rb b/app/mailers/emails/merge_requests.rb
index be085496731..6524d0c2087 100644
--- a/app/mailers/emails/merge_requests.rb
+++ b/app/mailers/emails/merge_requests.rb
@@ -40,6 +40,20 @@ module Emails
       mail_answer_thread(@merge_request, merge_request_thread_options(updated_by_user_id, recipient_id, reason))
     end
 
+    def removed_milestone_merge_request_email(recipient_id, merge_request_id, updated_by_user_id, reason = nil)
+      setup_merge_request_mail(merge_request_id, recipient_id)
+
+      mail_answer_thread(@merge_request, merge_request_thread_options(updated_by_user_id, recipient_id, reason))
+    end
+
+    def changed_milestone_merge_request_email(recipient_id, merge_request_id, milestone, updated_by_user_id, reason = nil)
+      setup_merge_request_mail(merge_request_id, recipient_id)
+
+      @milestone = milestone
+      @milestone_url = milestone_url(@milestone)
+      mail_answer_thread(@merge_request, merge_request_thread_options(updated_by_user_id, recipient_id, reason))
+    end
+
     def closed_merge_request_email(recipient_id, merge_request_id, updated_by_user_id, reason = nil)
       setup_merge_request_mail(merge_request_id, recipient_id)
 
diff --git a/app/mailers/previews/notify_preview.rb b/app/mailers/previews/notify_preview.rb
index 2f5b5483e9d..e7e8d96eca4 100644
--- a/app/mailers/previews/notify_preview.rb
+++ b/app/mailers/previews/notify_preview.rb
@@ -68,6 +68,14 @@ class NotifyPreview < ActionMailer::Preview
     Notify.issue_status_changed_email(user.id, issue.id, 'closed', user.id).message
   end
 
+  def removed_milestone_issue_email
+    Notify.removed_milestone_issue_email(user.id, issue.id, user.id)
+  end
+
+  def changed_milestone_issue_email
+    Notify.changed_milestone_issue_email(user.id, issue.id, milestone, user.id)
+  end
+
   def closed_merge_request_email
     Notify.closed_merge_request_email(user.id, issue.id, user.id).message
   end
@@ -80,6 +88,14 @@ class NotifyPreview < ActionMailer::Preview
     Notify.merged_merge_request_email(user.id, merge_request.id, user.id).message
   end
 
+  def removed_milestone_merge_request_email
+    Notify.removed_milestone_merge_request_email(user.id, merge_request.id, user.id)
+  end
+
+  def changed_milestone_merge_request_email
+    Notify.changed_milestone_merge_request_email(user.id, merge_request.id, milestone, user.id)
+  end
+
   def member_access_denied_email
     Notify.member_access_denied_email('project', project.id, user.id).message
   end
@@ -143,6 +159,10 @@ class NotifyPreview < ActionMailer::Preview
     @merge_request ||= project.merge_requests.first
   end
 
+  def milestone
+    @milestone ||= issue.milestone
+  end
+
   def pipeline
     @pipeline = Ci::Pipeline.last
   end
diff --git a/app/services/issuable_base_service.rb b/app/services/issuable_base_service.rb
index 3e8b9f84042..c388913ae65 100644
--- a/app/services/issuable_base_service.rb
+++ b/app/services/issuable_base_service.rb
@@ -3,6 +3,14 @@
 class IssuableBaseService < BaseService
   private
 
+  attr_accessor :params, :skip_milestone_email
+
+  def initialize(project, user = nil, params = {})
+    super
+
+    @skip_milestone_email = @params.delete(:skip_milestone_email)
+  end
+
   def filter_params(issuable)
     ability_name = :"admin_#{issuable.to_ability_name}"
 
diff --git a/app/services/issues/update_service.rb b/app/services/issues/update_service.rb
index b54b0bf6ef6..fba252b0bae 100644
--- a/app/services/issues/update_service.rb
+++ b/app/services/issues/update_service.rb
@@ -48,6 +48,8 @@ module Issues
         notification_service.async.relabeled_issue(issue, added_labels, current_user)
       end
 
+      handle_milestone_change(issue)
+
       added_mentions = issue.mentioned_users - old_mentioned_users
 
       if added_mentions.present?
@@ -91,6 +93,18 @@ module Issues
 
     private
 
+    def handle_milestone_change(issue)
+      return if skip_milestone_email
+
+      return unless issue.previous_changes.include?('milestone_id')
+
+      if issue.milestone.nil?
+        notification_service.async.removed_milestone_issue(issue, current_user)
+      else
+        notification_service.async.changed_milestone_issue(issue, issue.milestone, current_user)
+      end
+    end
+
     # rubocop: disable CodeReuse/ActiveRecord
     def get_issue_if_allowed(id, board_group_id = nil)
       return unless id
diff --git a/app/services/merge_requests/update_service.rb b/app/services/merge_requests/update_service.rb
index b112edbce7f..aacaf10d09c 100644
--- a/app/services/merge_requests/update_service.rb
+++ b/app/services/merge_requests/update_service.rb
@@ -58,6 +58,8 @@ module MergeRequests
         merge_request.mark_as_unchecked
       end
 
+      handle_milestone_change(merge_request)
+
       added_labels = merge_request.labels - old_labels
       if added_labels.present?
         notification_service.async.relabeled_merge_request(
@@ -105,6 +107,18 @@ module MergeRequests
 
     private
 
+    def handle_milestone_change(merge_request)
+      return if skip_milestone_email
+
+      return unless merge_request.previous_changes.include?('milestone_id')
+
+      if merge_request.milestone.nil?
+        notification_service.async.removed_milestone_merge_request(merge_request, current_user)
+      else
+        notification_service.async.changed_milestone_merge_request(merge_request, merge_request.milestone, current_user)
+      end
+    end
+
     def create_branch_change_note(issuable, branch_type, old_branch, new_branch)
       SystemNoteService.change_branch(
         issuable, issuable.project, current_user, branch_type,
diff --git a/app/services/milestones/destroy_service.rb b/app/services/milestones/destroy_service.rb
index 7cda802c120..87c7a282081 100644
--- a/app/services/milestones/destroy_service.rb
+++ b/app/services/milestones/destroy_service.rb
@@ -4,7 +4,7 @@ module Milestones
   class DestroyService < Milestones::BaseService
     def execute(milestone)
       Milestone.transaction do
-        update_params = { milestone: nil }
+        update_params = { milestone: nil, skip_milestone_email: true }
 
         milestone.issues.each do |issue|
           Issues::UpdateService.new(parent, current_user, update_params).execute(issue)
diff --git a/app/services/notification_service.rb b/app/services/notification_service.rb
index 50fa373025b..fb9c18ea75d 100644
--- a/app/services/notification_service.rb
+++ b/app/services/notification_service.rb
@@ -129,6 +129,14 @@ class NotificationService
     relabeled_resource_email(issue, added_labels, current_user, :relabeled_issue_email)
   end
 
+  def removed_milestone_issue(issue, current_user)
+    removed_milestone_resource_email(issue, current_user, :removed_milestone_issue_email)
+  end
+
+  def changed_milestone_issue(issue, new_milestone, current_user)
+    changed_milestone_resource_email(issue, new_milestone, current_user, :changed_milestone_issue_email)
+  end
+
   # When create a merge request we should send an email to:
   #
   #  * mr author
@@ -138,7 +146,6 @@ class NotificationService
   #  * users with custom level checked with "new merge request"
   #
   # In EE, approvers of the merge request are also included
-  #
   def new_merge_request(merge_request, current_user)
     new_resource_email(merge_request, :new_merge_request_email)
   end
@@ -208,6 +215,14 @@ class NotificationService
     relabeled_resource_email(merge_request, added_labels, current_user, :relabeled_merge_request_email)
   end
 
+  def removed_milestone_merge_request(merge_request, current_user)
+    removed_milestone_resource_email(merge_request, current_user, :removed_milestone_merge_request_email)
+  end
+
+  def changed_milestone_merge_request(merge_request, new_milestone, current_user)
+    changed_milestone_resource_email(merge_request, new_milestone, current_user, :changed_milestone_merge_request_email)
+  end
+
   def close_mr(merge_request, current_user)
     close_resource_email(merge_request, current_user, :closed_merge_request_email)
   end
@@ -500,6 +515,30 @@ class NotificationService
     end
   end
 
+  def removed_milestone_resource_email(target, current_user, method)
+    recipients = NotificationRecipientService.build_recipients(
+      target,
+      current_user,
+      action: 'removed_milestone'
+    )
+
+    recipients.each do |recipient|
+      mailer.send(method, recipient.user.id, target.id, current_user.id).deliver_later
+    end
+  end
+
+  def changed_milestone_resource_email(target, milestone, current_user, method)
+    recipients = NotificationRecipientService.build_recipients(
+      target,
+      current_user,
+      action: 'changed_milestone'
+    )
+
+    recipients.each do |recipient|
+      mailer.send(method, recipient.user.id, target.id, milestone, current_user.id).deliver_later
+    end
+  end
+
   def reopen_resource_email(target, current_user, method, status)
     recipients = NotificationRecipientService.build_recipients(target, current_user, action: "reopen")
 
diff --git a/app/views/notify/changed_milestone_issue_email.html.haml b/app/views/notify/changed_milestone_issue_email.html.haml
new file mode 100644
index 00000000000..7d5425fc72d
--- /dev/null
+++ b/app/views/notify/changed_milestone_issue_email.html.haml
@@ -0,0 +1,3 @@
+%p
+  Milestone changed to
+  %strong= link_to(@milestone.name, @milestone_url)
diff --git a/app/views/notify/changed_milestone_issue_email.text.erb b/app/views/notify/changed_milestone_issue_email.text.erb
new file mode 100644
index 00000000000..c5fc0b61518
--- /dev/null
+++ b/app/views/notify/changed_milestone_issue_email.text.erb
@@ -0,0 +1 @@
+Milestone changed to <%= @milestone.name %> ( <%= @milestone_url %> )
diff --git a/app/views/notify/changed_milestone_merge_request_email.html.haml b/app/views/notify/changed_milestone_merge_request_email.html.haml
new file mode 100644
index 00000000000..7d5425fc72d
--- /dev/null
+++ b/app/views/notify/changed_milestone_merge_request_email.html.haml
@@ -0,0 +1,3 @@
+%p
+  Milestone changed to
+  %strong= link_to(@milestone.name, @milestone_url)
diff --git a/app/views/notify/changed_milestone_merge_request_email.text.erb b/app/views/notify/changed_milestone_merge_request_email.text.erb
new file mode 100644
index 00000000000..c5fc0b61518
--- /dev/null
+++ b/app/views/notify/changed_milestone_merge_request_email.text.erb
@@ -0,0 +1 @@
+Milestone changed to <%= @milestone.name %> ( <%= @milestone_url %> )
diff --git a/app/views/notify/removed_milestone_issue_email.html.haml b/app/views/notify/removed_milestone_issue_email.html.haml
new file mode 100644
index 00000000000..7e9205b6491
--- /dev/null
+++ b/app/views/notify/removed_milestone_issue_email.html.haml
@@ -0,0 +1,2 @@
+%p
+  Milestone removed
diff --git a/app/views/notify/removed_milestone_issue_email.text.erb b/app/views/notify/removed_milestone_issue_email.text.erb
new file mode 100644
index 00000000000..0b83ed7a4c5
--- /dev/null
+++ b/app/views/notify/removed_milestone_issue_email.text.erb
@@ -0,0 +1 @@
+Milestone removed
diff --git a/app/views/notify/removed_milestone_merge_request_email.html.haml b/app/views/notify/removed_milestone_merge_request_email.html.haml
new file mode 100644
index 00000000000..7e9205b6491
--- /dev/null
+++ b/app/views/notify/removed_milestone_merge_request_email.html.haml
@@ -0,0 +1,2 @@
+%p
+  Milestone removed
diff --git a/app/views/notify/removed_milestone_merge_request_email.text.erb b/app/views/notify/removed_milestone_merge_request_email.text.erb
new file mode 100644
index 00000000000..0b83ed7a4c5
--- /dev/null
+++ b/app/views/notify/removed_milestone_merge_request_email.text.erb
@@ -0,0 +1 @@
+Milestone removed