Add label type to group and project labels lists

app/assets/stylesheets/pages/labels.scss

@@ -69,6 +69,20 @@
     }
   }
 
+  .label-type {
+    display: block;
+    margin-bottom: 10px;
+    margin-left: 50px;
+
+    @media (min-width: $screen-sm-min) {
+      display: inline-block;
+      width: 100px;
+      margin-left: 10px;
+      margin-bottom: 0;
+      vertical-align: middle;
+    }
+  }
+
   .label-description {
     display: block;
     margin-bottom: 10px;

app/views/groups/labels/index.html.haml

@@ -2,7 +2,7 @@
 
 .top-area.adjust
   .nav-text
-    Labels can be applied to issues and merge requests.
+    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)

app/views/shared/_label_row.html.haml

@@ -10,6 +10,8 @@
         = icon('star')
   %span.label-name
     = link_to_label(label, subject: @project, tooltip: false)
+  %span.label-type
+    = label.model_name.human.titleize
   - if label.description
     %span.label-description
       = markdown_field(label, :description)

db/migrate/20161017125927_add_unique_index_to_labels.rb

+class AddUniqueIndexToLabels < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = true
+  DOWNTIME_REASON = 'This migration removes duplicated labels.'
+
+  disable_ddl_transaction!
+
+  def up
+    select_all('SELECT title, COUNT(id) as cnt FROM labels GROUP BY project_id, title HAVING COUNT(id) > 1').each do |label|
+      label_title = quote_string(label['title'])
+      duplicated_ids = select_all("SELECT id FROM labels WHERE title = '#{label_title}' ORDER BY id ASC").map{ |label| label['id'] }
+      label_id = duplicated_ids.first
+      duplicated_ids.delete(label_id)
+
+      execute("UPDATE label_links SET label_id = #{label_id} WHERE label_id IN(#{duplicated_ids.join(",")})")
+      execute("DELETE FROM labels WHERE id IN(#{duplicated_ids.join(",")})")
+    end
+
+    remove_index :labels, column: :project_id if index_exists?(:labels, :project_id)
+    remove_index :labels, column: :title if index_exists?(:labels, :title)
+
+    add_concurrent_index :labels, [:group_id, :project_id, :title], unique: true
+  end
+
+  def down
+    remove_index :labels, column: [:group_id, :project_id, :title] if index_exists?(:labels, [:group_id, :project_id, :title], unique: true)
+
+    add_concurrent_index :labels, :project_id
+    add_concurrent_index :labels, :title
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20161017095000) do
+ActiveRecord::Schema.define(version: 20161017125927) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -543,9 +543,8 @@ ActiveRecord::Schema.define(version: 20161017095000) do
     t.integer "group_id"
   end
 
+  add_index "labels", ["group_id", "project_id", "title"], name: "index_labels_on_group_id_and_project_id_and_title", unique: true, using: :btree
   add_index "labels", ["group_id"], name: "index_labels_on_group_id", using: :btree
-  add_index "labels", ["project_id"], name: "index_labels_on_project_id", using: :btree
-  add_index "labels", ["title"], name: "index_labels_on_title", using: :btree
 
   create_table "lfs_objects", force: :cascade do |t|
     t.string "oid", null: false