Merge branch '23589-open-issue-for-mr' into 'master'

Create an issue for all unresolved discussions in an MR

See merge request !7180

app/controllers/projects/discussions_controller.rb

@@ -5,9 +5,7 @@ class Projects::DiscussionsController < Projects::ApplicationController
   before_action :authorize_resolve_discussion!
 
   def resolve
-    discussion.resolve!(current_user)
-
-    MergeRequests::ResolvedDiscussionNotificationService.new(project, current_user).execute(merge_request)
+    Discussions::ResolveService.new(project, current_user, merge_request: merge_request).execute(discussion)
 
     render json: {
       resolved_by: discussion.resolved_by.try(:name),

app/controllers/projects/issues_controller.rb

@@ -46,8 +46,9 @@ class Projects::IssuesController < Projects::ApplicationController
     params[:issue] ||= ActionController::Parameters.new(
       assignee_id: ""
     )
+    build_params = issue_params.merge(merge_request_for_resolving_discussions: merge_request_for_resolving_discussions)
+    @issue = @noteable = Issues::BuildService.new(project, current_user, build_params).execute
 
-    @issue = @noteable = @project.issues.new(issue_params)
     respond_with(@issue)
   end
 
@@ -75,7 +76,9 @@ class Projects::IssuesController < Projects::ApplicationController
   end
 
   def create
-    @issue = Issues::CreateService.new(project, current_user, issue_params.merge(request: request)).execute
+    extra_params = { request: request,
+                     merge_request_for_resolving_discussions: merge_request_for_resolving_discussions }
+    @issue = Issues::CreateService.new(project, current_user, issue_params.merge(extra_params)).execute
 
     respond_to do |format|
       format.html do
@@ -169,6 +172,14 @@ class Projects::IssuesController < Projects::ApplicationController
   alias_method :awardable, :issue
   alias_method :spammable, :issue
 
+  def merge_request_for_resolving_discussions
+    return unless merge_request_iid = params[:merge_request_for_resolving_discussions]
+
+    @merge_request_for_resolving_discussions ||= MergeRequestsFinder.new(current_user, project_id: project.id).
+                                                   execute.
+                                                   find_by(iid: merge_request_iid)
+  end
+
   def authorize_read_issue!
     return render_404 unless can?(current_user, :read_issue, @issue)
   end

app/models/discussion.rb

@@ -88,6 +88,10 @@ class Discussion
     @first_note ||= @notes.first
   end
 
+  def first_note_to_resolve
+    @first_note_to_resolve ||= notes.detect(&:to_be_resolved?)
+  end
+
   def last_note
     @last_note ||= @notes.last
   end

app/models/merge_request.rb

@@ -476,6 +476,14 @@ class MergeRequest < ActiveRecord::Base
     @diff_discussions ||= self.notes.diff_notes.discussions
   end
 
+  def resolvable_discussions
+    @resolvable_discussions ||= diff_discussions.select(&:to_be_resolved?)
+  end
+
+  def discussions_can_be_resolved_by?(user)
+    resolvable_discussions.all? { |discussion| discussion.can_resolve?(user) }
+  end
+
   def find_diff_discussion(discussion_id)
     notes = self.notes.diff_notes.where(discussion_id: discussion_id).fresh.to_a
     return if notes.empty?

app/models/note.rb

@@ -99,7 +99,7 @@ class Note < ActiveRecord::Base
     end
 
     def discussions
-      Discussion.for_notes(all)
+      Discussion.for_notes(fresh)
     end
 
     def grouped_diff_discussions

app/services/discussions/base_service.rb

+module Discussions
+  class BaseService < ::BaseService
+  end
+end

app/services/discussions/resolve_service.rb

+module Discussions
+  class ResolveService < Discussions::BaseService
+    def execute(one_or_more_discussions)
+      Array(one_or_more_discussions).each { |discussion| resolve_discussion(discussion) }
+    end
+
+    def resolve_discussion(discussion)
+      return unless discussion.can_resolve?(current_user)
+
+      discussion.resolve!(current_user)
+
+      MergeRequests::ResolvedDiscussionNotificationService.new(project, current_user).execute(merge_request)
+      SystemNoteService.discussion_continued_in_issue(discussion, project, current_user, follow_up_issue) if follow_up_issue
+    end
+
+    def merge_request
+      params[:merge_request]
+    end
+
+    def follow_up_issue
+      params[:follow_up_issue]
+    end
+  end
+end

app/services/issuable_base_service.rb

@@ -122,7 +122,8 @@ class IssuableBaseService < BaseService
       SlashCommands::InterpretService.new(project, current_user).
         execute(params[:description], issuable)
 
-    params[:description] = description
+    # Avoid a description already set on an issuable to be overwritten by a nil
+    params[:description] = description if params.has_key?(:description)
 
     params.merge!(command_params)
   end

app/services/issues/base_service.rb

 module Issues
   class BaseService < ::IssuableBaseService
+    attr_reader :merge_request_for_resolving_discussions
+
+    def initialize(*args)
+      super
+
+      @merge_request_for_resolving_discussions ||= params.delete(:merge_request_for_resolving_discussions)
+    end
+
     def hook_data(issue, action)
       issue_data = issue.to_hook_data(current_user)
       issue_url = Gitlab::UrlBuilder.build(issue)

app/services/issues/build_service.rb

+module Issues
+  class BuildService < Issues::BaseService
+    def execute
+      @issue = project.issues.new(issue_params)
+    end
+
+    def issue_params_with_info_from_merge_request
+      return {} unless merge_request_for_resolving_discussions
+
+      { title: title_from_merge_request, description: description_from_merge_request }
+    end
+
+    def title_from_merge_request
+      "Follow-up from \"#{merge_request_for_resolving_discussions.title}\""
+    end
+
+    def description_from_merge_request
+      if merge_request_for_resolving_discussions.resolvable_discussions.empty?
+        return "There are no unresolved discussions. "\
+               "Review the conversation in #{merge_request_for_resolving_discussions.to_reference}"
+      end
+
+      description = "The following discussions from #{merge_request_for_resolving_discussions.to_reference} should be addressed:"
+      [description, *items_for_discussions].join("\n\n")
+    end
+
+    def items_for_discussions
+      merge_request_for_resolving_discussions.resolvable_discussions.map { |discussion| item_for_discussion(discussion) }
+    end
+
+    def item_for_discussion(discussion)
+      first_note = discussion.first_note_to_resolve
+      other_note_count = discussion.notes.size - 1
+      creation_time = first_note.created_at.to_s(:medium)
+      note_url = Gitlab::UrlBuilder.build(first_note)
+
+      discussion_info = "- [ ] #{first_note.author.to_reference} commented in a discussion on [#{creation_time}](#{note_url}): "
+      discussion_info << " (+#{other_note_count} #{'comment'.pluralize(other_note_count)})" if other_note_count > 0
+
+      note_without_block_quotes = Banzai::Filter::BlockquoteFenceFilter.new(first_note.note).call
+      quote = ">>>\n#{note_without_block_quotes}\n>>>"
+
+      [discussion_info, quote].join("\n\n")
+    end
+
+    def issue_params
+      @issue_params ||= issue_params_with_info_from_merge_request.merge(params.slice(:title, :description))
+    end
+  end
+end

app/services/issues/create_service.rb

@@ -4,7 +4,8 @@ module Issues
       @request = params.delete(:request)
       @api = params.delete(:api)
 
-      @issue = project.issues.new
+      issue_attributes = params.merge(merge_request_for_resolving_discussions: merge_request_for_resolving_discussions)
+      @issue = BuildService.new(project, current_user, issue_attributes).execute
 
       create(@issue)
     end
@@ -18,6 +19,17 @@ module Issues
       notification_service.new_issue(issuable, current_user)
       todo_service.new_issue(issuable, current_user)
       user_agent_detail_service.create
+
+      if merge_request_for_resolving_discussions.try(:discussions_can_be_resolved_by?, current_user)
+        resolve_discussions_in_merge_request(issuable)
+      end
+    end
+
+    def resolve_discussions_in_merge_request(issue)
+      Discussions::ResolveService.new(project, current_user,
+                                      merge_request: merge_request_for_resolving_discussions,
+                                      follow_up_issue: issue).
+          execute(merge_request_for_resolving_discussions.resolvable_discussions)
     end
 
     private

app/services/system_note_service.rb

@@ -163,6 +163,14 @@ module SystemNoteService
     create_note(noteable: merge_request, project: project, author: author, note: body)
   end
 
+  def discussion_continued_in_issue(discussion, project, author, issue)
+    body = "Added #{issue.to_reference} to continue this discussion"
+    note_attributes = discussion.reply_attributes.merge(project: project, author: author, note: body)
+    note_attributes[:type] = note_attributes.delete(:note_type)
+
+    create_note(note_attributes)
+  end
+
   # Called when the title of a Noteable is changed
   #
   # noteable  - Noteable object that responds to `title`

app/views/projects/merge_requests/widget/open/_unresolved_discussions.html.haml

@@ -3,4 +3,8 @@
   This merge request has unresolved discussions
 
 %p
-  Please resolve these discussions to allow this merge request to be merged.
\ No newline at end of file
+  Please resolve these discussions
+  - if @project.issues_enabled? && can?(current_user, :create_issue, @project)
+    or
+    = link_to "open an issue to resolve them later", new_namespace_project_issue_path(@project.namespace, @project, merge_request_for_resolving_discussions: @merge_request.iid)
+  to allow this merge request to be merged.

app/views/shared/issuable/_form.html.haml

@@ -42,6 +42,21 @@
 
 = render 'shared/issuable/form/branch_chooser', issuable: issuable, form: form
 
+- if @merge_request_for_resolving_discussions
+  .form-group
+    .col-sm-10.col-sm-offset-2
+      - if @merge_request_for_resolving_discussions.discussions_can_be_resolved_by?(current_user)
+        = icon('exclamation-triangle')
+        Creating this issue will mark all discussions in
+        = link_to @merge_request_for_resolving_discussions.to_reference, merge_request_path(@merge_request_for_resolving_discussions)
+        as resolved.
+        = hidden_field_tag 'merge_request_for_resolving_discussions', @merge_request_for_resolving_discussions.iid
+      - else
+        = icon('exclamation-triangle')
+        You can't automatically mark all discussions in
+        = link_to @merge_request_for_resolving_discussions.to_reference, merge_request_path(@merge_request_for_resolving_discussions)
+        as resolved. Ask someone with sufficient rights to resolve the them.
+
 - is_footer = !(issuable.is_a?(MergeRequest) && issuable.new_record?)
 .row-content-block{class: (is_footer ? "footer-block" : "middle-block")}
   - if issuable.new_record?

changelogs/unreleased/23589-open-issue-for-mr.yml

+---
+title: Resolve all discussions in a merge request by creating an issue collecting
+  them
+merge_request: 7180
+author: Bob Van Landuyt

doc/api/issues.md

@@ -330,6 +330,7 @@ POST /projects/:id/issues
 | `labels`        | string  | no  | Comma-separated label names for an issue  |
 | `created_at`    | string  | no  | Date time string, ISO 8601 formatted, e.g. `2016-03-11T03:45:40Z` (requires admin or project owner rights) |
 | `due_date`      | string  | no  | Date time string in the format YEAR-MONTH-DAY, e.g. `2016-03-11` |
+| `merge_request_for_resolving_discussions` | integer | no       | The IID of a merge request in which to resolve all issues. This will fill the issue with a default description and mark all discussions as resolved. When passing a description or title, these values will take precedence over the default values. |
 
 ```bash
 curl --request POST --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/projects/4/issues?title=Issues%20with%20auth&labels=bug

doc/user/project/merge_requests/merge_request_discussion_resolution.md

@@ -37,7 +37,8 @@ resolved discussions tracker.
 
 > [Introduced][ce-7125] in GitLab 8.14.
 
-You can prevent merge requests from being merged until all discussions are resolved.
+You can prevent merge requests from being merged until all discussions are
+resolved.
 
 Navigate to your project's settings page, select the
 **Only allow merge requests to be merged if all discussions are resolved** check
@@ -50,8 +51,26 @@ are resolved.
 
 ![Only allow merge if all the discussions are resolved message](img/only_allow_merge_if_all_discussions_are_resolved_msg.png)
 
+### Move all unresolved discussions in a merge request to an issue
+
+> [Introduced][ce-7180] (Currently on Backlog)
+
+To delegate unresolved discussions to a new issue you can click the link **open
+an issue to resolve them later**.
+
+This will prepare an issue with content referring to the merge request and
+discussions.
+
+![Issue mentioning discussions in a merge request](img/preview_issue_for_discussions.png)
+
+Hitting **Submit issue** will cause all discussions to be marked as resolved and
+add a note referring to the newly created issue.
+
+You can now proceed to merge the merge request from the UI.
+
 [ce-5022]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5022
 [ce-7125]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7125
+[ce-7180]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7180
 [resolve-discussion-button]: img/resolve_discussion_button.png
 [resolve-comment-button]: img/resolve_comment_button.png
 [discussion-view]: img/discussion_view.png

lib/api/issues.rb

@@ -28,6 +28,14 @@ module API
 
         new_params
       end
+
+      def merge_request_for_resolving_discussions
+        return unless merge_request_iid = params[:merge_request_for_resolving_discussions]
+
+        @merge_request_for_resolving_discussions ||= MergeRequestsFinder.new(current_user, project_id: user_project.id).
+                                                       execute.
+                                                       find_by(iid: merge_request_iid)
+      end
     end
 
     resource :issues do
@@ -160,15 +168,19 @@ module API
       #   created_at (optional)                              - Date time string, ISO 8601 formatted
       #   due_date (optional)                                - Date time string in the format YEAR-MONTH-DAY
       #   confidential (optional)                            - Boolean parameter if the issue should be confidential
+      #   merge_request_for_resolving_discussions (optional) - The IID of a merge request for which to resolve discussions
       # Example Request:
       #   POST /projects/:id/issues
       post ':id/issues' do
         required_attributes! [:title]
 
-        keys = [:title, :description, :assignee_id, :milestone_id, :due_date, :confidential, :labels]
+        keys = [:title, :description, :assignee_id, :milestone_id, :due_date, :confidential, :labels, :merge_request_for_resolving_discussions]
         keys << :created_at if current_user.admin? || user_project.owner == current_user
         attrs = attributes_for_keys(keys)
 
+        attrs[:labels] = params[:labels] if params[:labels]
+        attrs[:merge_request_for_resolving_discussions] = merge_request_for_resolving_discussions if params[:merge_request_for_resolving_discussions]
+
         # Convert and filter out invalid confidential flags
         attrs['confidential'] = to_boolean(attrs['confidential'])
         attrs.delete('confidential') if attrs['confidential'].nil?

spec/controllers/projects/issues_controller_spec.rb

@@ -55,6 +55,30 @@ describe Projects::IssuesController do
   end
 
   describe 'GET #new' do
+    context 'internal issue tracker' do
+      before do
+        sign_in(user)
+        project.team << [user, :developer]
+      end
+
+      it 'builds a new issue' do
+        get :new, namespace_id: project.namespace.path, project_id: project
+
+        expect(assigns(:issue)).to be_a_new(Issue)
+      end
+
+      it 'fills in an issue for a merge request' do
+        project_with_repository = create(:project)
+        project_with_repository.team << [user, :developer]
+        mr = create(:merge_request_with_diff_notes, source_project: project_with_repository)
+
+        get :new, namespace_id: project_with_repository.namespace.path, project_id: project_with_repository, merge_request_for_resolving_discussions: mr.iid
+
+        expect(assigns(:issue).title).not_to be_empty
+        expect(assigns(:issue).description).not_to be_empty
+      end
+    end
+
     context 'external issue tracker' do
       it 'redirects to the external issue tracker' do
         external = double(new_issue_path: 'https://example.com/issues/new')
@@ -272,6 +296,42 @@ describe Projects::IssuesController do
   end
 
   describe 'POST #create' do
+    context 'resolving discussions in MergeRequest' do
+      let(:discussion) { Discussion.for_diff_notes([create(:diff_note_on_merge_request)]).first }
+      let(:merge_request) { discussion.noteable }
+      let(:project) { merge_request.source_project }
+
+      before do
+        project.team << [user, :master]
+        sign_in user
+      end
+
+      let(:merge_request_params) do
+        { merge_request_for_resolving_discussions: merge_request.iid }
+      end
+
+      def post_issue(issue_params)
+        post :create, namespace_id: project.namespace.to_param, project_id: project.to_param, issue: issue_params, merge_request_for_resolving_discussions: merge_request.iid
+      end
+
+      it 'creates an issue for the project' do
+        expect { post_issue({ title: 'Hello' }) }.to change { project.issues.reload.size }.by(1)
+      end
+
+      it "doesn't overwrite given params" do
+        post_issue(description: 'Manually entered description')
+
+        expect(assigns(:issue).description).to eq('Manually entered description')
+      end
+
+      it 'resolves the discussion in the merge_request' do
+        post_issue(title: 'Hello')
+        discussion.first_note.reload
+
+        expect(discussion.resolved?).to eq(true)
+      end
+    end
+
     context 'Akismet is enabled' do
       before do
         allow_any_instance_of(SpamService).to receive(:check_for_spam?).and_return(true)

spec/features/issues/create_issue_for_discussions_in_merge_request_spec.rb

+require 'rails_helper'
+
+feature 'Resolving all open discussions in a merge request from an issue', feature: true do
+  let(:user) { create(:user) }
+  let(:project) { create(:project, only_allow_merge_if_all_discussions_are_resolved: true) }
+  let(:merge_request) { create(:merge_request, source_project: project) }
+  let!(:discussion) { Discussion.for_diff_notes([create(:diff_note_on_merge_request, noteable: merge_request, project: project)]).first }
+
+  before do
+    project.team << [user, :master]
+    login_as user
+  end
+
+  context 'with the internal tracker disabled' do
+    before do
+      project.project_feature.update_attribute(:issues_access_level, ProjectFeature::DISABLED)
+      visit namespace_project_merge_request_path(project.namespace, project, merge_request)
+    end
+
+    it 'does not show a link to create a new issue' do
+      expect(page).not_to have_link 'open an issue to resolve them later'
+    end
+  end
+
+  context 'merge request has discussions that need to be resolved' do
+    before do
+      visit namespace_project_merge_request_path(project.namespace, project, merge_request)
+    end
+
+    it 'shows a warning that the merge request contains unresolved discussions' do
+      expect(page).to have_content 'This merge request has unresolved discussions'
+    end
+
+    it 'has a link to resolve all discussions by creating an issue' do
+      page.within '.mr-widget-body' do
+        expect(page).to have_link 'open an issue to resolve them later', href: new_namespace_project_issue_path(project.namespace, project, merge_request_for_resolving_discussions: merge_request.iid)
+      end
+    end
+
+    context 'creating an issue for discussions' do
+      before do
+        page.click_link 'open an issue to resolve them later', href: new_namespace_project_issue_path(project.namespace, project, merge_request_for_resolving_discussions: merge_request.iid)
+      end
+
+      it 'shows an issue with the title filled in' do
+        title_field = page.find_field('issue[title]')
+
+        expect(title_field.value).to include(merge_request.title)
+      end
+
+      it 'has a mention of the discussion in the description'  do
+        description_field = page.find_field('issue[description]')
+
+        expect(description_field.value).to include(discussion.first_note.note)
+      end
+
+      it 'has a hidden field for the merge request' do
+        merge_request_field = find('#merge_request_for_resolving_discussions', visible: false)
+
+        expect(merge_request_field.value).to eq(merge_request.iid.to_s)
+      end
+
+      it 'can create a new issue for the project' do
+        expect { click_button 'Submit issue' }.to change { project.issues.reload.size }.by(1)
+      end
+
+      it 'resolves the discussion in the merge request' do
+        click_button 'Submit issue'
+
+        discussion.first_note.reload
+
+        expect(discussion.resolved?).to eq(true)
+      end
+    end
+  end
+end

spec/models/discussion_spec.rb

@@ -521,6 +521,15 @@ describe Discussion, model: true do
     end
   end
 
+  describe "#first_note_to_resolve" do
+    it "returns the first not that still needs to be resolved" do
+      allow(first_note).to receive(:to_be_resolved?).and_return(false)
+      allow(second_note).to receive(:to_be_resolved?).and_return(true)
+
+      expect(subject.first_note_to_resolve).to eq(second_note)
+    end
+  end
+
   describe "#collapsed?" do
     context "when a diff discussion" do
       before do

spec/models/merge_request_spec.rb

@@ -1127,6 +1127,46 @@ describe MergeRequest, models: true do
       allow(subject).to receive(:diff_discussions).and_return([first_discussion, second_discussion, third_discussion])
     end
 
+    describe '#resolvable_discussions' do
+      before do
+        allow(first_discussion).to receive(:to_be_resolved?).and_return(true)
+        allow(second_discussion).to receive(:to_be_resolved?).and_return(false)
+        allow(third_discussion).to receive(:to_be_resolved?).and_return(false)
+      end
+
+      it 'includes only discussions that need to be resolved' do
+        expect(subject.resolvable_discussions).to eq([first_discussion])
+      end
+    end
+
+    describe '#discussions_can_be_resolved_by? user' do
+      let(:user) { build(:user) }
+
+      context 'all discussions can be resolved by the user' do
+        before do
+          allow(first_discussion).to receive(:can_resolve?).with(user).and_return(true)
+          allow(second_discussion).to receive(:can_resolve?).with(user).and_return(true)
+          allow(third_discussion).to receive(:can_resolve?).with(user).and_return(true)
+        end
+
+        it 'allows a user to resolve the discussions' do
+          expect(subject.discussions_can_be_resolved_by?(user)).to be(true)
+        end
+      end
+
+      context 'one discussion cannot be resolved by the user' do
+        before do
+          allow(first_discussion).to receive(:can_resolve?).with(user).and_return(true)
+          allow(second_discussion).to receive(:can_resolve?).with(user).and_return(true)
+          allow(third_discussion).to receive(:can_resolve?).with(user).and_return(false)
+        end
+
+        it 'allows a user to resolve the discussions' do
+          expect(subject.discussions_can_be_resolved_by?(user)).to be(false)
+        end
+      end
+    end
+
     describe "#discussions_resolvable?" do
       context "when all discussions are unresolvable" do
         before do

spec/requests/api/issues_spec.rb

@@ -692,6 +692,32 @@ describe API::Issues, api: true  do
       ])
     end
 
+    context 'resolving issues in a merge request' do
+      let(:discussion) { Discussion.for_diff_notes([create(:diff_note_on_merge_request)]).first }
+      let(:merge_request) { discussion.noteable }
+      let(:project) { merge_request.source_project }
+      before do
+        project.team << [user, :master]
+        post api("/projects/#{project.id}/issues", user),
+             title: 'New Issue',
+             merge_request_for_resolving_discussions: merge_request.iid
+      end
+
+      it 'creates a new project issue' do
+        expect(response).to have_http_status(:created)
+      end
+
+      it 'resolves the discussions in a merge request' do
+        discussion.first_note.reload
+
+        expect(discussion.resolved?).to be(true)
+      end
+
+      it 'assigns a description to the issue mentioning the merge request' do
+        expect(json_response['description']).to include(merge_request.to_reference)
+      end
+    end
+
     context 'with due date' do
       it 'creates a new project issue' do
         due_date = 2.weeks.from_now.strftime('%Y-%m-%d')

spec/services/discussions/resolve_service_spec.rb

+require 'spec_helper'
+
+describe Discussions::ResolveService do
+  describe '#execute' do
+    let(:discussion) { Discussion.for_diff_notes([create(:diff_note_on_merge_request)]).first }
+    let(:project) { merge_request.project }
+    let(:merge_request) { discussion.noteable }
+    let(:user) { create(:user) }
+    let(:service) { described_class.new(discussion.noteable.project, user, merge_request: merge_request) }
+
+    before do
+      project.team << [user, :master]
+    end
+
+    it "doesn't resolve discussions the user can't resolve" do
+      expect(discussion).to receive(:can_resolve?).with(user).and_return(false)
+
+      service.execute(discussion)
+
+      expect(discussion.resolved?).to be(false)
+    end
+
+    it 'resolves the discussion' do
+      service.execute(discussion)
+
+      expect(discussion.resolved?).to be(true)
+    end
+
+    it 'executes the notification service' do
+      expect_any_instance_of(MergeRequests::ResolvedDiscussionNotificationService).to receive(:execute).with(discussion.noteable)
+
+      service.execute(discussion)
+    end
+
+    it 'adds a system note to the discussion' do
+      issue = create(:issue, project: project)
+
+      expect(SystemNoteService).to receive(:discussion_continued_in_issue).with(discussion, project, user, issue)
+      service = described_class.new(project, user, merge_request: merge_request, follow_up_issue: issue)
+      service.execute(discussion)
+    end
+
+    it 'can resolve multiple discussions at once' do
+      other_discussion = Discussion.for_diff_notes([create(:diff_note_on_merge_request, noteable: discussion.noteable, project: discussion.noteable.source_project)]).first
+
+      service.execute([discussion, other_discussion])
+
+      expect(discussion.resolved?).to be(true)
+      expect(other_discussion.resolved?).to be(true)
+    end
+  end
+end

spec/services/issues/build_service_spec.rb

+require 'spec_helper.rb'
+
+describe Issues::BuildService, services: true do
+  let(:project) { create(:project) }
+  let(:user) { create(:user) }
+
+  before do
+    project.team << [user, :developer]
+  end
+
+  context 'for discussions in a merge request' do
+    let(:merge_request) { create(:merge_request_with_diff_notes, source_project: project) }
+    let(:issue) { described_class.new(project, user, merge_request_for_resolving_discussions: merge_request).execute }
+
+    def position_on_line(line_number)
+      Gitlab::Diff::Position.new(
+        old_path: "files/ruby/popen.rb",
+        new_path: "files/ruby/popen.rb",
+        old_line: nil,
+        new_line: line_number,
+        diff_refs: merge_request.diff_refs
+      )
+    end
+
+    describe '#items_for_discussions' do
+      it 'has an item for each discussion' do
+        create(:diff_note_on_merge_request, noteable: merge_request, project: merge_request.source_project, position: position_on_line(13))
+        service = described_class.new(project, user, merge_request_for_resolving_discussions: merge_request)
+
+        service.execute
+
+        expect(service.items_for_discussions.size).to eq(2)
+      end
+    end
+
+    describe '#item_for_discussion' do
+      let(:service) { described_class.new(project, user, merge_request_for_resolving_discussions: merge_request) }
+
+      it 'mentions the author of the note' do
+        discussion = Discussion.new([create(:diff_note_on_merge_request, author: create(:user, username: 'author'))])
+        expect(service.item_for_discussion(discussion)).to include('@author')
+      end
+
+      it 'wraps the note in a blockquote' do
+        note_text = "This is a string\n"\
+                    ">>>\n"\
+                    "with a blockquote\n"\
+                    "> That has a quote\n"\
+                    ">>>\n"
+        note_result = "This is a string\n"\
+                    "> with a blockquote\n"\
+                    "> > That has a quote\n"
+        discussion = Discussion.new([create(:diff_note_on_merge_request, note: note_text)])
+        expect(service.item_for_discussion(discussion)).to include(">>>\n#{note_result}\n>>>")
+      end
+    end
+
+    describe '#execute' do
+      it 'has the merge request reference in the title' do
+        expect(issue.title).to include(merge_request.title)
+      end
+
+      it 'has the reference of the merge request in the description' do
+        expect(issue.description).to include(merge_request.to_reference)
+      end
+
+      it 'does not assign title when a title was given' do
+        issue = described_class.new(project, user,
+                                    merge_request_for_resolving_discussions: merge_request,
+                                    title: 'What an issue').execute
+
+        expect(issue.title).to eq('What an issue')
+      end
+
+      it 'does not assign description when a description was given' do
+        issue = described_class.new(project, user,
+                                    merge_request_for_resolving_discussions: merge_request,
+                                    description: 'Fix at your earliest conveignance').execute
+
+        expect(issue.description).to eq('Fix at your earliest conveignance')
+      end
+
+      describe 'with multiple discussions' do
+        before do
+          create(:diff_note_on_merge_request, noteable: merge_request, project: merge_request.target_project, position: position_on_line(15))
+        end
+
+        it 'mentions all the authors in the description' do
+          authors = merge_request.diff_discussions.map(&:author)
+
+          expect(issue.description).to include(*authors.map(&:to_reference))
+        end
+
+        it 'has a link for each unresolved discussion in the description' do
+          notes = merge_request.diff_discussions.map(&:first_note)
+          links = notes.map { |note| Gitlab::UrlBuilder.build(note) }
+
+          expect(issue.description).to include(*links)
+        end
+
+        it 'mentions additional notes' do
+          create_list(:diff_note_on_merge_request, 2, noteable: merge_request, project: merge_request.target_project, position: position_on_line(15))
+
+          expect(issue.description).to include('(+2 comments)')
+        end
+      end
+    end
+  end
+
+  context 'For a merge request without discussions' do
+    let(:merge_request) { create(:merge_request, source_project: project) }
+
+    describe '#execute' do
+      it 'mentions the merge request in the description' do
+        issue = described_class.new(project, user, merge_request_for_resolving_discussions: merge_request).execute
+
+        expect(issue.description).to include("Review the conversation in #{merge_request.to_reference}")
+      end
+    end
+  end
+
+  describe '#execute' do
+    it 'builds a new issues with given params' do
+      issue = described_class.new(project, user, title: 'Issue #1', description: 'Issue description').execute
+
+      expect(issue.title).to eq('Issue #1')
+      expect(issue.description).to eq('Issue description')
+    end
+  end
+end

spec/services/issues/create_service_spec.rb

@@ -136,5 +136,48 @@ describe Issues::CreateService, services: true do
     end
 
     it_behaves_like 'new issuable record that supports slash commands'
+
+    context 'for a merge request' do
+      let(:discussion) { Discussion.for_diff_notes([create(:diff_note_on_merge_request)]).first }
+      let(:merge_request) { discussion.noteable }
+      let(:project) { merge_request.source_project }
+      let(:opts) { { merge_request_for_resolving_discussions: merge_request } }
+
+      before do
+        project.team << [user, :master]
+      end
+
+      it 'resolves the discussion for the merge request' do
+        described_class.new(project, user, opts).execute
+        discussion.first_note.reload
+
+        expect(discussion.resolved?).to be(true)
+      end
+
+      it 'added a system note to the discussion' do
+        described_class.new(project, user, opts).execute
+
+        reloaded_discussion = MergeRequest.find(merge_request.id).discussions.first
+
+        expect(reloaded_discussion.last_note.system).to eq(true)
+      end
+
+      it 'assigns the title and description for the issue' do
+        issue = described_class.new(project, user, opts).execute
+
+        expect(issue.title).not_to be_nil
+        expect(issue.description).not_to be_nil
+      end
+
+      it 'can set nil explicityly to the title and description' do
+        issue = described_class.new(project, user,
+                                    merge_request_for_resolving_discussions: merge_request,
+                                    description: nil,
+                                    title: nil).execute
+
+        expect(issue.description).to be_nil
+        expect(issue.title).to be_nil
+      end
+    end
   end
 end

spec/services/system_note_service_spec.rb

@@ -712,4 +712,32 @@ describe SystemNoteService, services: true do
       end
     end
   end
+
+  describe '.discussion_continued_in_issue' do
+    let(:discussion) { Discussion.for_diff_notes([create(:diff_note_on_merge_request)]).first }
+    let(:merge_request) { discussion.noteable }
+    let(:project) { merge_request.source_project }
+    let(:issue) { create(:issue, project: project) }
+    let(:user) { create(:user) }
+
+    def reloaded_merge_request
+      MergeRequest.find(merge_request.id)
+    end
+
+    before do
+      project.team << [user, :developer]
+    end
+
+    it 'creates a new note in the discussion' do
+      # we need to completely rebuild the merge request object, or the `@discussions` on the merge request are not reloaded.
+      expect { SystemNoteService.discussion_continued_in_issue(discussion, project, user, issue) }.
+        to change { reloaded_merge_request.discussions.first.notes.size }.by(1)
+    end
+
+    it 'mentions the created issue in the system note' do
+      note = SystemNoteService.discussion_continued_in_issue(discussion, project, user, issue)
+
+      expect(note.note).to include(issue.to_reference)
+    end
+  end
 end