Merge branch '20968-add-setting-to-check-unresolved-discussion' into 'master'

Add setting to only allow merge requests to be merged when all discussions are resolved

_Originally opened at !6385 by @rodolfoasantos._

- - -

## What does this MR do?
Based on #20968 this merge request adds setting only to allow merge requests to be merged when all discussions are resolved. 

## Are there points in the code the reviewer needs to double check?
Check if there are other points to add the resolved discussion setting

## Why was this MR needed?
Add the possibility to configure the project to only accept merge request when all discussions are resolved

## Screenshots

![only_allow_merge_if_all_discussions_are_resolved](/uploads/9388db9421da0214590ffab6fb29f985/only_allow_merge_if_all_discussions_are_resolved.png)

![only_allow_merge_if_all_discussions_are_resolved_msg](/uploads/b1bba0c72ad67d3a1b34718baa08526e/only_allow_merge_if_all_discussions_are_resolved_msg.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #20968

See merge request !7125

5 files changed, 21 insertions, 1 deletions

diff --git a/app/controllers/projects_controller.rb b/app/controllers/projects_controller.rb
index bce5e29d8d8..6988527a3be 100644
--- a/app/controllers/projects_controller.rb
+++ b/app/controllers/projects_controller.rb
@@ -335,6 +335,7 @@ class ProjectsController < Projects::ApplicationController
       :visibility_level, :import_url, :last_activity_at, :namespace_id, :avatar,
       :build_allow_git_fetch, :build_timeout_in_minutes, :build_coverage_regex,
       :public_builds, :only_allow_merge_if_build_succeeds, :request_access_enabled,
+      :only_allow_merge_if_all_discussions_are_resolved,
       :lfs_enabled, project_feature_attributes
     )
   end
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 6b8ac3fb48b..d76feb9680e 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -425,6 +425,7 @@ class MergeRequest < ActiveRecord::Base
     return false if work_in_progress?
     return false if broken?
     return false unless skip_ci_check || mergeable_ci_state?
+    return false unless mergeable_discussions_state?
 
     true
   end
@@ -493,6 +494,12 @@ class MergeRequest < ActiveRecord::Base
     discussions_resolvable? && diff_discussions.none?(&:to_be_resolved?)
   end
 
+  def mergeable_discussions_state?
+    return true unless project.only_allow_merge_if_all_discussions_are_resolved?
+
+    discussions_resolved?
+  end
+
   def hook_attrs
     attrs = {
       source: source_project.try(:hook_attrs),
diff --git a/app/views/projects/_merge_request_settings.html.haml b/app/views/projects/_merge_request_settings.html.haml
index 80053dd501b..6e143c4b570 100644
--- a/app/views/projects/_merge_request_settings.html.haml
+++ b/app/views/projects/_merge_request_settings.html.haml
@@ -12,3 +12,7 @@
           %span.descr
             Builds need to be configured to enable this feature.
             = link_to icon('question-circle'), help_page_path('user/project/merge_requests/merge_when_build_succeeds', anchor: 'only-allow-merge-requests-to-be-merged-if-the-build-succeeds')
+      .checkbox
+        = f.label :only_allow_merge_if_all_discussions_are_resolved do
+          = f.check_box :only_allow_merge_if_all_discussions_are_resolved
+          %strong Only allow merge requests to be merged if all discussions are resolved
diff --git a/app/views/projects/merge_requests/widget/_open.html.haml b/app/views/projects/merge_requests/widget/_open.html.haml
index 842b6df310d..01314eb37d0 100644
--- a/app/views/projects/merge_requests/widget/_open.html.haml
+++ b/app/views/projects/merge_requests/widget/_open.html.haml
@@ -23,8 +23,10 @@
       = render 'projects/merge_requests/widget/open/merge_when_build_succeeds'
     - elsif !@merge_request.can_be_merged_by?(current_user)
       = render 'projects/merge_requests/widget/open/not_allowed'
-    - elsif !@merge_request.mergeable_ci_state? && @pipeline && @pipeline.failed?
+    - elsif !@merge_request.mergeable_ci_state?
       = render 'projects/merge_requests/widget/open/build_failed'
+    - elsif !@merge_request.mergeable_discussions_state?
+      = render 'projects/merge_requests/widget/open/unresolved_discussions'
     - elsif @merge_request.can_be_merged? || resolved_conflicts
       = render 'projects/merge_requests/widget/open/accept'
 
diff --git a/app/views/projects/merge_requests/widget/open/_unresolved_discussions.html.haml b/app/views/projects/merge_requests/widget/open/_unresolved_discussions.html.haml
new file mode 100644
index 00000000000..35d5677ee37
--- /dev/null
+++ b/app/views/projects/merge_requests/widget/open/_unresolved_discussions.html.haml
@@ -0,0 +1,6 @@
+%h4
+  = icon('exclamation-triangle')
+  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