Merge branch 'feature/group-level-labels' into 'master'

Add group level labels

## What does this MR do?

Add group level labels.

## Are there points in the code the reviewer needs to double check?

* `LabelsFinder`
* `Gitlab::Gfm::ReferenceRewriter`
* `Banzai::Filter::LabelReferenceFilter`

## Why was this MR needed?

We'll be adding more feature that allow you to do cross-project management of issues.

## Screenshots (if relevant)

* Group Labels
    ![Group Labels](/uploads/2244c06ad68eae4fb246fb4c81bf8060/2.png)

* Project Labels
    ![Project Labels](/uploads/c5839516d2282b51f7418d9dadbeceb4/1.png)

* Expanded references for group labels when moving issue to another project
    ![Expanded references for group labels when moving issue to another project](/uploads/0c9ab248a8420d4978d59349ae3d42e5/3.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [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
- [ ] 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)
- [ ] 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?

#19997

See merge request !6425

19 files changed, 120 insertions, 73 deletions

diff --git a/app/views/groups/labels/destroy.js.haml b/app/views/groups/labels/destroy.js.haml
new file mode 100644
index 00000000000..3dfbfc77c0d
--- /dev/null
+++ b/app/views/groups/labels/destroy.js.haml
@@ -0,0 +1,2 @@
+- if @group.labels.empty?
+  $('.labels').load(document.URL + ' .nothing-here-block').hide().fadeIn(1000)
diff --git a/app/views/groups/labels/edit.html.haml b/app/views/groups/labels/edit.html.haml
new file mode 100644
index 00000000000..836981fc6fd
--- /dev/null
+++ b/app/views/groups/labels/edit.html.haml
@@ -0,0 +1,7 @@
+- page_title 'Edit', @label.name, 'Labels'
+
+%h3.page-title
+  Edit Label
+%hr
+
+= render 'shared/labels/form', url: group_label_path(@group, @label), back_path: @previous_labels_path
diff --git a/app/views/groups/labels/index.html.haml b/app/views/groups/labels/index.html.haml
new file mode 100644
index 00000000000..70783a63409
--- /dev/null
+++ b/app/views/groups/labels/index.html.haml
@@ -0,0 +1,20 @@
+- page_title 'Labels'
+
+.top-area.adjust
+  .nav-text
+    Labels can be applied to issues and merge requests. Group labels are available for any project within the group.
+
+  .nav-controls
+    - if can?(current_user, :admin_label, @group)
+      = link_to new_group_label_path(@group), class: "btn btn-new" do
+        New label
+
+.labels
+  .other-labels
+    - if @labels.present?
+      %ul.content-list.manage-labels-list.js-other-labels
+        = render partial: 'shared/label', collection: @labels, as: :label
+        = paginate @labels, theme: 'gitlab'
+    - else
+      .nothing-here-block
+        No labels created yet.
diff --git a/app/views/groups/labels/new.html.haml b/app/views/groups/labels/new.html.haml
new file mode 100644
index 00000000000..2be87460b1d
--- /dev/null
+++ b/app/views/groups/labels/new.html.haml
@@ -0,0 +1,8 @@
+- page_title 'New Label'
+- header_title group_title(@group, 'Labels', group_labels_path(@group))
+
+%h3.page-title
+  New Label
+%hr
+
+= render 'shared/labels/form', url: group_labels_path, back_path: @previous_labels_path
diff --git a/app/views/layouts/nav/_group.html.haml b/app/views/layouts/nav/_group.html.haml
index 27ac1760166..f7edb47b666 100644
--- a/app/views/layouts/nav/_group.html.haml
+++ b/app/views/layouts/nav/_group.html.haml
@@ -13,6 +13,10 @@
       = link_to activity_group_path(@group), title: 'Activity' do
         %span
           Activity
+    = nav_link(controller: [:group, :labels]) do
+      = link_to group_labels_path(@group), title: 'Labels' do
+        %span
+          Labels
     = nav_link(controller: [:group, :milestones]) do
       = link_to group_milestones_path(@group), title: 'Milestones' do
         %span
diff --git a/app/views/projects/issues/_issue.html.haml b/app/views/projects/issues/_issue.html.haml
index 8b1a8a8a2d9..c80210d6ff4 100644
--- a/app/views/projects/issues/_issue.html.haml
+++ b/app/views/projects/issues/_issue.html.haml
@@ -50,7 +50,7 @@
     - if issue.labels.any?
        
       - issue.labels.each do |label|
-        = link_to_label(label, project: issue.project)
+        = link_to_label(label, subject: issue.project)
     - if issue.tasks?
        
       %span.task-status
diff --git a/app/views/projects/labels/_label.html.haml b/app/views/projects/labels/_label.html.haml
deleted file mode 100644
index 71f7f354d72..00000000000
--- a/app/views/projects/labels/_label.html.haml
+++ /dev/null
@@ -1,50 +0,0 @@
-- label_css_id = dom_id(label)
-%li{id: label_css_id, data: { id: label.id } }
-  = render "shared/label_row", label: label
-
-  .visible-xs.visible-sm-inline-block.visible-md-inline-block.dropdown
-    %button.btn.btn-default.label-options-toggle{ data: { toggle: "dropdown" } }
-      Options
-      = icon('caret-down')
-    .dropdown-menu.dropdown-menu-align-right
-      %ul
-        %li
-          = link_to_label(label, type: :merge_request) do
-            = pluralize label.open_merge_requests_count, 'merge request'
-        %li
-          = link_to_label(label) do
-            = pluralize label.open_issues_count(current_user), 'open issue'
-        - if current_user
-          %li.label-subscription{ data: { url: toggle_subscription_namespace_project_label_path(@project.namespace, @project, label) } }
-            %a.js-subscribe-button.label-subscribe-button.subscription-status{ role: "button", href: "#", data: { toggle: "tooltip", status: label_subscription_status(label) } }
-              %span= label_subscription_toggle_button_text(label)
-        - if can? current_user, :admin_label, @project
-          %li
-            = link_to "Edit", edit_namespace_project_label_path(@project.namespace, @project, label)
-          %li
-            = link_to "Delete", namespace_project_label_path(@project.namespace, @project, label), title: "Delete", method: :delete, remote: true, data: {confirm: "Remove this label? Are you sure?"}
-
-  .pull-right.hidden-xs.hidden-sm.hidden-md
-    = link_to_label(label, type: :merge_request, css_class: 'btn btn-transparent btn-action') do
-      = pluralize label.open_merge_requests_count, 'merge request'
-    = link_to_label(label, css_class: 'btn btn-transparent btn-action') do
-      = pluralize label.open_issues_count(current_user), 'open issue'
-
-    - if current_user
-      .label-subscription.inline{ data: { url: toggle_subscription_namespace_project_label_path(@project.namespace, @project, label) } }
-        %button.js-subscribe-button.label-subscribe-button.btn.btn-transparent.btn-action.subscription-status{ type: "button", title: label_subscription_toggle_button_text(label), data: { toggle: "tooltip", status: label_subscription_status(label) } }
-          %span.sr-only= label_subscription_toggle_button_text(label)
-          = icon('eye', class: 'label-subscribe-button-icon')
-          = icon('spinner spin', class: 'label-subscribe-button-loading')
-
-    - if can? current_user, :admin_label, @project
-      = link_to edit_namespace_project_label_path(@project.namespace, @project, label), title: "Edit", class: 'btn btn-transparent btn-action', data: {toggle: "tooltip"} do
-        %span.sr-only Edit
-        = icon('pencil-square-o')
-      = link_to namespace_project_label_path(@project.namespace, @project, label), title: "Delete", class: 'btn btn-transparent btn-action remove-row', method: :delete, remote: true, data: {confirm: "Remove this label? Are you sure?", toggle: "tooltip"} do
-        %span.sr-only Delete
-        = icon('trash-o')
-
-  - if current_user
-    :javascript
-      new Subscription('##{dom_id(label)} .label-subscription');
diff --git a/app/views/projects/labels/destroy.js.haml b/app/views/projects/labels/destroy.js.haml
index d59563b122a..8d09e2bda11 100644
--- a/app/views/projects/labels/destroy.js.haml
+++ b/app/views/projects/labels/destroy.js.haml
@@ -1,2 +1,2 @@
-- if @project.labels.size == 0
+- if @labels.empty?
   $('.labels').load(document.URL + ' .nothing-here-block').hide().fadeIn(1000)
diff --git a/app/views/projects/labels/edit.html.haml b/app/views/projects/labels/edit.html.haml
index 52b187e7e58..a80a07b52e6 100644
--- a/app/views/projects/labels/edit.html.haml
+++ b/app/views/projects/labels/edit.html.haml
@@ -6,4 +6,4 @@
   %h3.page-title
     Edit Label
   %hr
-  = render 'form'
+  = render 'shared/labels/form', url: namespace_project_label_path(@project.namespace.becomes(Namespace), @project, @label), back_path: namespace_project_labels_path(@project.namespace, @project)
diff --git a/app/views/projects/labels/index.html.haml b/app/views/projects/labels/index.html.haml
index db66a0edbd8..f135bf6f6b4 100644
--- a/app/views/projects/labels/index.html.haml
+++ b/app/views/projects/labels/index.html.haml
@@ -16,21 +16,22 @@
   .labels
     - if can?(current_user, :admin_label, @project)
       -# Only show it in the first page
-      - hide = @project.labels.empty? || (params[:page].present? && params[:page] != '1')
+      - hide = @available_labels.empty? || (params[:page].present? && params[:page] != '1')
       .prioritized-labels{ class: ('hide' if hide) }
         %h5 Prioritized Labels
         %ul.content-list.manage-labels-list.js-prioritized-labels{ "data-url" => set_priorities_namespace_project_labels_path(@project.namespace, @project) }
           %p.empty-message{ class: ('hidden' unless @prioritized_labels.empty?) } No prioritized labels yet
           - if @prioritized_labels.present?
-            = render @prioritized_labels
+            = render partial: 'shared/label', collection: @prioritized_labels, as: :label
+
     .other-labels
       - if can?(current_user, :admin_label, @project)
         %h5{ class: ('hide' if hide) } Other Labels
-      - if @labels.present?
-        %ul.content-list.manage-labels-list.js-other-labels
-          = render @labels
+      %ul.content-list.manage-labels-list.js-other-labels
+        - if @labels.present?
+          = render partial: 'shared/label', collection: @labels, as: :label
         = paginate @labels, theme: 'gitlab'
-      - else
+      - if @labels.blank?
         .nothing-here-block
           - if can?(current_user, :admin_label, @project)
             Create a label or #{link_to 'generate a default set of labels', generate_namespace_project_labels_path(@project.namespace, @project), method: :post}.
diff --git a/app/views/projects/labels/new.html.haml b/app/views/projects/labels/new.html.haml
index a1bb66cfb6c..f0d9be744d1 100644
--- a/app/views/projects/labels/new.html.haml
+++ b/app/views/projects/labels/new.html.haml
@@ -6,4 +6,4 @@
   %h3.page-title
     New Label
   %hr
-  = render 'form'
+  = render 'shared/labels/form', url: namespace_project_labels_path(@project.namespace.becomes(Namespace), @project), back_path: namespace_project_labels_path(@project.namespace, @project)
diff --git a/app/views/projects/merge_requests/_merge_request.html.haml b/app/views/projects/merge_requests/_merge_request.html.haml
index 68fb7d5a414..12408068834 100644
--- a/app/views/projects/merge_requests/_merge_request.html.haml
+++ b/app/views/projects/merge_requests/_merge_request.html.haml
@@ -62,7 +62,7 @@
     - if merge_request.labels.any?
        
       - merge_request.labels.each do |label|
-        = link_to_label(label, project: merge_request.project, type: 'merge_request')
+        = link_to_label(label, subject: merge_request.project, type: :merge_request)
     - if merge_request.tasks?
        
       %span.task-status
diff --git a/app/views/shared/_label.html.haml b/app/views/shared/_label.html.haml
new file mode 100644
index 00000000000..40c8d2af226
--- /dev/null
+++ b/app/views/shared/_label.html.haml
@@ -0,0 +1,53 @@
+- label_css_id = dom_id(label)
+- open_issues_count = label.open_issues_count(current_user, @project)
+- open_merge_requests_count = label.open_merge_requests_count(current_user, @project)
+
+%li{id: label_css_id, data: { id: label.id } }
+  = render "shared/label_row", label: label
+
+  .visible-xs.visible-sm-inline-block.visible-md-inline-block.dropdown
+    %button.btn.btn-default.label-options-toggle{ data: { toggle: "dropdown" } }
+      Options
+      = icon('caret-down')
+    .dropdown-menu.dropdown-menu-align-right
+      %ul
+        %li
+          = link_to_label(label, subject: @project, type: :merge_request) do
+            = pluralize open_merge_requests_count, 'merge request'
+        %li
+          = link_to_label(label, subject: @project) do
+            = pluralize open_issues_count, 'open issue'
+        - if current_user
+          %li.label-subscription{ data: toggle_subscription_data(label) }
+            %a.js-subscribe-button.label-subscribe-button.subscription-status{ role: "button", href: "#", data: { toggle: "tooltip", status: label_subscription_status(label) } }
+              %span= label_subscription_toggle_button_text(label)
+        - if can?(current_user, :admin_label, label)
+          %li
+            = link_to 'Edit', edit_label_path(label)
+          %li
+            = link_to 'Delete', destroy_label_path(label), title: 'Delete', method: :delete, remote: true, data: {confirm: 'Remove this label? Are you sure?'}
+
+  .pull-right.hidden-xs.hidden-sm.hidden-md
+    = link_to_label(label, subject: @project, type: :merge_request, css_class: 'btn btn-transparent btn-action') do
+      = pluralize open_merge_requests_count, 'merge request'
+    = link_to_label(label, subject: @project, css_class: 'btn btn-transparent btn-action') do
+      = pluralize open_issues_count, 'open issue'
+
+    - if current_user
+      .label-subscription.inline{ data: toggle_subscription_data(label) }
+        %button.js-subscribe-button.label-subscribe-button.btn.btn-transparent.btn-action.subscription-status{ type: "button", title: label_subscription_toggle_button_text(label), data: { toggle: "tooltip", status: label_subscription_status(label) } }
+          %span.sr-only= label_subscription_toggle_button_text(label)
+          = icon('eye', class: 'label-subscribe-button-icon', disabled: label.is_a?(GroupLabel))
+          = icon('spinner spin', class: 'label-subscribe-button-loading')
+
+    - if can?(current_user, :admin_label, label)
+      = link_to edit_label_path(label), title: "Edit", class: 'btn btn-transparent btn-action', data: {toggle: "tooltip"} do
+        %span.sr-only Edit
+        = icon('pencil-square-o')
+      = link_to destroy_label_path(label), title: "Delete", class: 'btn btn-transparent btn-action remove-row', method: :delete, remote: true, data: {confirm: label_deletion_confirm_text(label), toggle: "tooltip"} do
+        %span.sr-only Delete
+        = icon('trash-o')
+
+  - if current_user && label.is_a?(ProjectLabel)
+    :javascript
+      new Subscription('##{dom_id(label)} .label-subscription');
diff --git a/app/views/shared/_label_row.html.haml b/app/views/shared/_label_row.html.haml
index 6f593e8dff9..d28f9421ecf 100644
--- a/app/views/shared/_label_row.html.haml
+++ b/app/views/shared/_label_row.html.haml
@@ -3,13 +3,16 @@
     .draggable-handler
       = icon('bars')
     .js-toggle-priority.toggle-priority{ data: { url: remove_priority_namespace_project_label_path(@project.namespace, @project, label),
-      dom_id: dom_id(label) } }
+      dom_id: dom_id(label), type: label.type } }
       %button.add-priority.btn.has-tooltip{ title: 'Prioritize', :'data-placement' => 'top' }
         = icon('star-o')
       %button.remove-priority.btn.has-tooltip{ title: 'Remove priority', :'data-placement' => 'top' }
         = icon('star')
   %span.label-name
-    = link_to_label(label, tooltip: false)
+    = link_to_label(label, subject: @project, tooltip: false)
+  - if defined?(@project) && @project.group.present?
+    %span.label-type
+      = label.model_name.human.titleize
   - if label.description
     %span.label-description
       = markdown_field(label, :description)
diff --git a/app/views/shared/_labels_row.html.haml b/app/views/shared/_labels_row.html.haml
index e324d0e5203..21b37a7c9ae 100644
--- a/app/views/shared/_labels_row.html.haml
+++ b/app/views/shared/_labels_row.html.haml
@@ -1,5 +1,5 @@
 - labels.each do |label|
   %span.label-row.btn-group{ role: "group", aria: { label: label.name }, style: "color: #{text_color_for_bg(label.color)}" }
-    = link_to_label(label, css_class: 'btn btn-transparent')
+    = link_to_label(label, subject: @project, css_class: 'btn btn-transparent')
     %button.btn.btn-transparent.label-remove.js-label-filter-remove{ type: "button", style: "background-color: #{label.color};", data: { label: label.title } }
       = icon("times")
diff --git a/app/views/shared/issuable/_filter.html.haml b/app/views/shared/issuable/_filter.html.haml
index 6b43a76c404..ed93857e6d4 100644
--- a/app/views/shared/issuable/_filter.html.haml
+++ b/app/views/shared/issuable/_filter.html.haml
@@ -78,11 +78,10 @@
           = hidden_field_tag :state_event, params[:state_event]
           .filter-item.inline
             = button_tag "Update #{type.to_s.humanize(capitalize: false)}", class: "btn update_selected_issues btn-save"
-
-  - if !@labels.nil?
-    .row-content-block.second-block.filtered-labels{ class: ("hidden" if !@labels.any?) }
-      - if @labels.any?
-        = render "shared/labels_row", labels: @labels
+  - has_labels = @labels && @labels.any?
+  .row-content-block.second-block.filtered-labels{ class: ("hidden" unless has_labels) }
+    - if has_labels
+      = render 'shared/labels_row', labels: @labels
 
 :javascript
   new UsersSelect();
diff --git a/app/views/shared/issuable/_form.html.haml b/app/views/shared/issuable/_form.html.haml
index ee5c21f0762..d410755cad1 100644
--- a/app/views/shared/issuable/_form.html.haml
+++ b/app/views/shared/issuable/_form.html.haml
@@ -95,7 +95,7 @@
           .issuable-form-select-holder
             = render "shared/issuable/milestone_dropdown", selected: issuable.milestone, name: "#{issuable.class.model_name.param_key}[milestone_id]", show_any: false, show_upcoming: false, extra_class: "js-issuable-form-dropdown js-dropdown-keep-input", dropdown_title: "Select milestone"
       .form-group
-        - has_labels = issuable.project.labels.any?
+        - has_labels = @labels && @labels.any?
         = f.label :label_ids, "Labels", class: "control-label #{"col-lg-4" if has_due_date}"
         = f.hidden_field :label_ids, multiple: true, value: ''
         .col-sm-10{ class: "#{"col-lg-8" if has_due_date} #{'issuable-form-padding-top' if !has_labels}" }
diff --git a/app/views/shared/issuable/_sidebar.html.haml b/app/views/shared/issuable/_sidebar.html.haml
index ba9f0c27661..7363ead09ff 100644
--- a/app/views/shared/issuable/_sidebar.html.haml
+++ b/app/views/shared/issuable/_sidebar.html.haml
@@ -107,7 +107,7 @@
                   = dropdown_content do
                     .js-due-date-calendar
 
-      - if issuable.project.labels.any?
+      - if @labels && @labels.any?
         - selected_labels = issuable.labels
         .block.labels
           .sidebar-collapsed-icon.js-sidebar-labels-tooltip{ title: issuable_labels_tooltip(issuable.labels_array), data: { placement: "left", container: "body" } }
diff --git a/app/views/projects/labels/_form.html.haml b/app/views/shared/labels/_form.html.haml
index 6ab6ae50389..647e05e5ff7 100644
--- a/app/views/projects/labels/_form.html.haml
+++ b/app/views/shared/labels/_form.html.haml
@@ -1,4 +1,4 @@
-= form_for [@project.namespace.becomes(Namespace), @project, @label], html: { class: 'form-horizontal label-form js-quick-submit js-requires-input' } do |f|
+= form_for @label, as: :label, url: url, html: { class: 'form-horizontal label-form js-quick-submit js-requires-input' } do |f|
   = form_errors(@label)
 
   .form-group
@@ -30,4 +30,4 @@
       = f.submit 'Save changes', class: 'btn btn-save js-save-button'
     - else
       = f.submit 'Create Label', class: 'btn btn-create js-save-button'
-    = link_to "Cancel", namespace_project_labels_path(@project.namespace, @project), class: 'btn btn-cancel'
+    = link_to 'Cancel', back_path, class: 'btn btn-cancel'