Merge branch 'multiple_assignees_review' into 'multiple-assignees-fe-issues-list'

# Conflicts:
#   app/serializers/issuable_entity.rb
#   app/views/projects/issues/_issue.html.haml

app/assets/javascripts/boards/components/modal/filters.js

@@ -15,7 +15,7 @@ export default {
     this.filteredSearch = new FilteredSearchBoards(this.store);
     this.filteredSearch.removeTokens();
   },
-  beforeDestroy() {
+  destroyed() {
     this.filteredSearch.cleanup();
     FilteredSearchContainer.container = document;
     this.store.path = '';

app/assets/javascripts/boards/components/modal/index.js

@@ -65,8 +65,15 @@ require('./empty_state');
       },
       filter: {
         handler() {
-          this.page = 1;
-          this.loadIssues(true);
+          if (this.$el.tagName) {
+            this.page = 1;
+            this.filterLoading = true;
+
+            this.loadIssues(true)
+              .then(() => {
+                this.filterLoading = false;
+              });
+          }
         },
         deep: true,
       },
@@ -140,14 +147,14 @@ require('./empty_state');
             :image="blankStateImage"
             :issue-link-base="issueLinkBase"
             :root-path="rootPath"
-            v-if="!loading && showList"></modal-list>
+            v-if="!loading && showList && !filterLoading"></modal-list>
           <empty-state
             v-if="showEmptyState"
             :image="blankStateImage"
             :new-issue-path="newIssuePath"></empty-state>
           <section
             class="add-issues-list text-center"
-            v-if="loading">
+            v-if="loading || filterLoading">
             <div class="add-issues-list-loading">
               <i class="fa fa-spinner fa-spin"></i>
             </div>

app/assets/javascripts/boards/stores/modal_store.js

@@ -15,6 +15,7 @@
         searchTerm: '',
         loading: false,
         loadingNewPage: false,
+        filterLoading: false,
         page: 1,
         perPage: 50,
         filter: {

app/assets/javascripts/weight_select.js

@@ -30,9 +30,9 @@
             $loading.fadeOut();
             $selectbox.hide();
             if (data.weight != null) {
-              $value.html(data.weight);
+              $value.html(`<strong>${data.weight}</strong>`);
             } else {
-              $value.html('None');
+              $value.html('<span class="no-value">None</span>');
             }
             return $sidebarCollapsedValue.html(data.weight);
           });

app/assets/stylesheets/framework/buttons.scss

@@ -68,23 +68,19 @@
 }
 
 @mixin btn-green {
-  @include btn-color($green-light, $border-green-light, $green-normal, $border-green-normal, $green-dark, $border-green-dark, $white-light);
+  @include btn-color($green-500, $green-600, $green-600, $green-700, $green-700, $green-800, $white-light);
 }
 
 @mixin btn-blue {
-  @include btn-color($blue-light, $border-blue-light, $blue-normal, $border-blue-normal, $blue-dark, $border-blue-dark, $white-light);
-}
-
-@mixin btn-blue-medium {
-  @include btn-color($blue-medium-light, $border-blue-light, $blue-medium, $border-blue-normal, $blue-medium-dark, $border-blue-dark, $white-light);
+  @include btn-color($blue-500, $blue-600, $blue-600, $blue-700, $blue-700, $blue-800, $white-light);
 }
 
 @mixin btn-orange {
-  @include btn-color($orange-light, $border-orange-light, $orange-normal, $border-orange-normal, $orange-dark, $border-orange-dark, $white-light);
+  @include btn-color($orange-500, $orange-600, $orange-600, $orange-700, $orange-700, $orange-800, $white-light);
 }
 
 @mixin btn-red {
-  @include btn-color($red-light, $border-red-light, $red-normal, $border-red-normal, $red-dark, $border-red-dark, $white-light);
+  @include btn-color($red-500, $red-600, $red-600, $red-700, $red-700, $red-800, $white-light);
 }
 
 @mixin btn-gray {
@@ -145,11 +141,11 @@
     &.btn-new,
     &.btn-create,
     &.btn-save {
-      @include btn-outline($white-light, $border-green-light, $border-green-light, $green-light, $white-light, $border-green-light, $green-normal, $border-green-normal);
+      @include btn-outline($white-light, $green-600, $green-500, $green-500, $white-light, $green-600, $green-600, $green-700);
     }
 
     &.btn-remove {
-      @include btn-outline($white-light, $border-red-light, $border-red-light, $red-light, $white-light, $border-red-light, $red-normal, $border-red-normal);
+      @include btn-outline($white-light, $red-500, $red-500, $red-500, $white-light, $red-600, $red-600, $red-700);
     }
   }
 
@@ -157,11 +153,8 @@
     @include btn-gray;
   }
 
-  &.btn-primary {
-    @include btn-blue-medium;
-  }
-
   &.btn-info,
+  &.btn-primary,
   &.btn-register {
     @include btn-blue;
   }
@@ -171,11 +164,11 @@
   }
 
   &.btn-close {
-    @include btn-outline($white-light, $border-orange-light, $border-orange-light, $orange-light, $white-light, $border-orange-light, $orange-normal, $border-orange-normal);
+    @include btn-outline($white-light, $orange-600, $orange-500, $orange-500, $white-light, $orange-600, $orange-600, $orange-700);
   }
 
   &.btn-spam {
-    @include btn-outline($white-light, $border-red-light, $border-red-light, $red-light, $white-light, $border-red-light, $red-normal, $border-red-normal);
+    @include btn-outline($white-light, $red-500, $red-500, $red-500, $white-light, $red-600, $red-600, $red-700);
   }
 
   &.btn-danger,
@@ -360,7 +353,7 @@
 
 .btn-inverted {
   &-secondary {
-    @include btn-outline($white-light, $border-blue-light, $border-blue-light, $blue-light, $white-light, $border-blue-light, $blue-normal, $border-blue-normal);
+    @include btn-outline($white-light, $blue-500, $blue-500, $blue-500, $white-light, $blue-600, $blue-600, $blue-700);
   }
 }
 

app/assets/stylesheets/framework/dropdowns.scss

@@ -199,7 +199,7 @@
       text-decoration: none;
 
       .badge {
-        background-color: darken($row-hover, 5%);
+        background-color: darken($dropdown-link-hover-bg, 5%);
       }
     }
 

app/assets/stylesheets/framework/forms.scss

@@ -177,34 +177,34 @@ label {
 }
 
 .gl-field-error {
-  color: $red-normal;
+  color: $red-500;
 }
 
 .gl-show-field-errors {
   .gl-field-success-outline {
-    border: 1px solid $green-normal;
+    border: 1px solid $green-600;
 
     &:focus {
-      box-shadow: 0 0 0 1px $green-normal inset, 0 1px 1px $gl-field-focus-shadow inset, 0 0 4px 0 $green-normal;
+      box-shadow: 0 0 0 1px $green-600 inset, 0 1px 1px $gl-field-focus-shadow inset, 0 0 4px 0 $green-600;
       border: 0 none;
     }
   }
 
   .gl-field-error-outline {
-    border: 1px solid $red-normal;
+    border: 1px solid $red-500;
 
     &:focus {
-      box-shadow: 0 0 0 1px $red-normal inset, 0 1px 1px $gl-field-focus-shadow inset, 0 0 4px 0 $gl-field-focus-shadow-error;
+      box-shadow: 0 0 0 1px $red-500 inset, 0 1px 1px $gl-field-focus-shadow inset, 0 0 4px 0 $gl-field-focus-shadow-error;
       border: 0 none;
     }
   }
 
   .gl-field-success-message {
-    color: $green-normal;
+    color: $green-600;
   }
 
   .gl-field-error-message {
-    color: $red-normal;
+    color: $red-500;
   }
 
   .gl-field-hint {

app/assets/stylesheets/framework/header.scss

@@ -265,7 +265,7 @@ header {
   }
 
   .impersonation i {
-    color: $red-normal;
+    color: $red-500;
   }
 }
 

app/assets/stylesheets/framework/icons.scss

 .ci-status-icon-success {
-  color: $gl-success;
+  color: $green-500;
 
   svg {
-    fill: $gl-success;
+    fill: $green-500;
   }
 }
 
@@ -17,18 +17,18 @@
 .ci-status-icon-pending,
 .ci-status-icon-failed_with_warnings,
 .ci-status-icon-success_with_warnings {
-  color: $gl-warning;
+  color: $orange-500;
 
   svg {
-    fill: $gl-warning;
+    fill: $orange-500;
   }
 }
 
 .ci-status-icon-running {
-  color: $blue-normal;
+  color: $blue-400;
 
   svg {
-    fill: $blue-normal;
+    fill: $blue-400;
   }
 }
 

app/assets/stylesheets/framework/issue_box.scss

@@ -33,7 +33,7 @@
   }
 
   &.status-box-open {
-    background-color: $green-light;
+    background-color: $green-500;
   }
 
   &.status-box-expired {

app/assets/stylesheets/framework/layout.scss

@@ -76,28 +76,28 @@ body {
   /* Stripe the background colors so that adjacent alert-warnings are distinct from one another */
   .alert-warning {
     transition: background-color 0.15s, border-color 0.15s;
-    background-color: lighten($gl-warning, 4%);
-    border-color: lighten($gl-warning, 4%);
+    background-color: $orange-500;
+    border-color: $orange-500;
   }
 
   .alert-warning + .alert-warning {
-    background-color: $gl-warning;
-    border-color: $gl-warning;
+    background-color: $orange-600;
+    border-color: $orange-600;
   }
 
   .alert-warning + .alert-warning + .alert-warning {
-    background-color: darken($gl-warning, 4%);
-    border-color: darken($gl-warning, 4%);
+    background-color: $orange-700;
+    border-color: $orange-700;
   }
 
   .alert-warning + .alert-warning + .alert-warning + .alert-warning {
-    background-color: darken($gl-warning, 8%);
-    border-color: darken($gl-warning, 8%);
+    background-color: $orange-800;
+    border-color: $orange-800;
   }
 
   .alert-warning:only-of-type {
-    background-color: $gl-warning;
-    border-color: $gl-warning;
+    background-color: $orange-500;
+    border-color: $orange-500;
   }
 }
 

app/assets/stylesheets/framework/lists.scss

@@ -122,7 +122,7 @@ ul.content-list {
     }
 
     .member-group-link {
-      color: $blue-normal;
+      color: $blue-600;
     }
 
     .description {

app/assets/stylesheets/framework/tw_bootstrap_variables.scss

@@ -31,6 +31,7 @@ $border-radius-small: 3px !default;
 //
 $text-color: $gl-text-color;
 $link-color: $gl-link-color;
+$link-hover-color: $gl-link-hover-color;
 
 
 //== Typography
@@ -73,7 +74,7 @@ $pagination-hover-color: $gl-text-color;
 $pagination-hover-bg: $row-hover;
 $pagination-hover-border: $border-color;
 
-$pagination-active-color: $blue-dark;
+$pagination-active-color: $blue-600;
 $pagination-active-bg: $white-light;
 $pagination-active-border: $border-color;
 
@@ -135,8 +136,8 @@ $well-border: #eee;
 //
 //##
 
-$code-color: #c7254e;
-$code-bg: #f9f2f4;
+$code-color: $red-600;
+$code-bg: lighten($red-50, 2%);
 
 $kbd-color: $white-light;
 $kbd-bg: #333;

app/assets/stylesheets/pages/boards.scss

@@ -536,9 +536,9 @@
   right: -3px;
   top: -3px;
   width: 17px;
-  background-color: $blue-light;
+  background-color: $blue-500;
   color: $white-light;
-  border: 1px solid $border-blue-light;
+  border: 1px solid $blue-600;
   font-size: 9px;
   line-height: 15px;
   border-radius: 50%;

app/assets/stylesheets/pages/environments.scss

@@ -239,18 +239,18 @@
   margin: 1px;
 
   &-finished {
-    background-color: lighten($green-light, 25%);
-    border-color: $green-light;
+    background-color: $green-100;
+    border-color: $green-400;
   }
 
   &-deploying {
-    background-color: lighten($green-light, 40%);
-    border-color: $green-light;
+    background-color: $green-50;
+    border-color: $green-400;
   }
 
   &-failed {
-    background-color: lighten($red-light, 20%);
-    border-color: $red-normal;
+    background-color: $red-200;
+    border-color: $red-500;
   }
 
   &-ready {

app/assets/stylesheets/pages/issuable.scss

@@ -530,12 +530,12 @@
 
     &.over_estimate {
       .meter-fill {
-        background: $red-light;
+        background: $red-500;
       }
 
       .time-remaining,
       .compare-value.spent {
-        color: $red-light;
+        color: $red-500;
       }
     }
   }

app/assets/stylesheets/pages/issues.scss

@@ -69,21 +69,17 @@ ul.related-merge-requests > li {
   height: 20px;
   border-radius: 3px;
   line-height: 18px;
-  border: 1px solid;
 
   &.merged {
-    border-color: darken($blue-normal, 10%);
-    background: $blue-normal;
+    background: $blue-500;
   }
 
   &.closed {
-    border-color: darken($red-normal, 10%);
-    background: $red-normal;
+    background: $red-500;
   }
 
   &.open {
-    border: 1px solid darken($green-normal, 10%);
-    background: $green-normal;
+    background: $green-500;
   }
 }
 
@@ -143,7 +139,7 @@ ul.related-merge-requests > li {
   }
 
   .export-checkmark {
-    color: $green-light;
+    color: $green-400;
   }
 }
 

app/assets/stylesheets/pages/login.scss

@@ -85,11 +85,11 @@
       }
 
       .username .validation-success {
-        color: $green-normal;
+        color: $green-600;
       }
 
       .username .validation-error {
-        color: $red-normal;
+        color: $red-500;
       }
     }
   }

app/assets/stylesheets/pages/members.scss

@@ -158,7 +158,7 @@
   > p {
     float: left;
     margin-bottom: 10px;
-    color: $orange-normal;
+    color: $orange-600;
 
     @media (min-width: $screen-sm-min) {
       padding-left: 55px;

app/assets/stylesheets/pages/merge_conflicts.scss

@@ -255,7 +255,7 @@ $colors: (
 
     &.saved {
       .editor {
-        border-top: solid 2px $border-green-extra-light;
+        border-top: solid 2px $green-200;
       }
     }
 

app/assets/stylesheets/pages/merge_requests.scss

@@ -535,7 +535,7 @@
   }
 
   .fa-info-circle {
-    color: $orange-normal;
+    color: $orange-500;
     padding-right: 5px;
   }
 }

app/assets/stylesheets/pages/milestone.scss

@@ -63,7 +63,7 @@
   }
 
   .remaining-days {
-    color: $orange-light;
+    color: $orange-600;
   }
 
   .milestone-stats-and-buttons {

app/assets/stylesheets/pages/notes.scss

@@ -462,17 +462,18 @@ ul.notes {
   background: $white-light;
   padding: 1px 5px;
   font-size: 12px;
-  color: $gl-link-color;
+  color: $blue-500;
   margin-left: -55px;
   position: absolute;
   z-index: 10;
   width: 23px;
   height: 23px;
-  border: 1px solid $border-color;
+  border: 1px solid $blue-500;
   transition: transform .1s ease-in-out;
 
   &:hover {
-    background: $gl-info;
+    background: $blue-500;
+    border-color: $blue-600;
     color: $white-light;
     transform: scale(1.15);
   }

app/assets/stylesheets/pages/pipelines.scss

@@ -671,51 +671,71 @@
 
   // Dropdown button animation in mini pipeline graph
   &.ci-status-icon-success {
-    border-color: $gl-success;
-    color: $gl-success;
+    border-color: $green-500;
+    color: $green-500;
 
     &:hover,
     &:focus,
     &:active {
-      background-color: rgba($gl-success, 0.1);
-      border-color: $gl-success;
+      background-color: $green-50;
+      border-color: $green-600;
+      color: $green-600;
+
+      svg {
+        fill: $green-600;
+      }
     }
   }
 
   &.ci-status-icon-failed {
-    border-color: $gl-danger;
-    color: $gl-danger;
+    border-color: $red-500;
+    color: $red-500;
 
     &:hover,
     &:focus,
     &:active {
-      background-color: rgba($gl-danger, 0.1);
-      border-color: $gl-danger;
+      background-color: $red-50;
+      border-color: $red-600;
+      color: $red-600;
+
+      svg {
+        fill: $red-600;
+      }
     }
   }
 
   &.ci-status-icon-pending,
   &.ci-status-icon-success_with_warnings {
-    border-color: $gl-warning;
-    color: $gl-warning;
+    border-color: $orange-500;
+    color: $orange-500;
 
     &:hover,
     &:focus,
     &:active {
-      background-color: rgba($gl-warning, 0.1);
-      border-color: $gl-warning;
+      background-color: $orange-50;
+      border-color: $orange-600;
+      color: $orange-600;
+
+      svg {
+        fill: $orange-600;
+      }
     }
   }
 
   &.ci-status-icon-running {
-    border-color: $blue-normal;
-    color: $blue-normal;
+    border-color: $blue-400;
+    color: $blue-400;
 
     &:hover,
     &:focus,
     &:active {
-      background-color: rgba($blue-normal, 0.1);
-      border-color: $blue-normal;
+      background-color: $blue-50;
+      border-color: $blue-600;
+      color: $blue-600;
+
+      svg {
+        fill: $blue-600;
+      }
     }
   }
 

app/assets/stylesheets/pages/profile.scss

@@ -74,7 +74,6 @@
   display: inline;
 
   a {
-    color: $blue-dark;
     text-decoration: none;
   }
 }

app/assets/stylesheets/pages/sherlock.scss

@@ -28,6 +28,6 @@ table .sherlock-code {
 }
 
 .sherlock-line-samples-table .slow {
-  color: $red-light;
+  color: $red-500;
   font-weight: bold;
 }

app/assets/stylesheets/pages/status.scss

@@ -21,42 +21,41 @@
 
     &.ci-failed,
     &.ci-failed_with_warnings {
-      color: $gl-danger;
-      border-color: $gl-danger;
+      color: $red-500;
+      border-color: $red-500;
 
       &:not(span):hover {
-        background-color: rgba($gl-danger, .07);
+        background-color: $red-50;
+        color: $red-600;
+        border-color: $red-600;
+
+        svg {
+          fill: $red-600;
+        }
       }
 
       svg {
-        fill: $gl-danger;
+        fill: $red-500;
       }
     }
 
     &.ci-success,
     &.ci-success_with_warnings {
-      color: $gl-success;
-      border-color: $gl-success;
+      color: $green-600;
+      border-color: $green-500;
 
       &:not(span):hover {
-        background-color: rgba($gl-success, .07);
-      }
-
-      svg {
-        fill: $gl-success;
-      }
-    }
-
-    &.ci-info {
-      color: $gl-info;
-      border-color: $gl-info;
+        background-color: $green-50;
+        color: $green-700;
+        border-color: $green-600;
 
-      &:not(span):hover {
-        background-color: rgba($gl-info, .07);
+        svg {
+          fill: $green-600;
+        }
       }
 
       svg {
-        fill: $gl-info;
+        fill: $green-500;
       }
     }
 
@@ -75,28 +74,41 @@
     }
 
     &.ci-pending {
-      color: $gl-warning;
-      border-color: $gl-warning;
+      color: $orange-600;
+      border-color: $orange-500;
 
       &:not(span):hover {
-        background-color: rgba($gl-warning, .07);
+        background-color: $orange-50;
+        color: $orange-700;
+        border-color: $orange-600;
+
+        svg {
+          fill: $orange-600;
+        }
       }
 
       svg {
-        fill: $gl-warning;
+        fill: $orange-500;
       }
     }
 
+    &.ci-info,
     &.ci-running {
-      color: $blue-normal;
-      border-color: $blue-normal;
+      color: $blue-500;
+      border-color: $blue-500;
 
       &:not(span):hover {
-        background-color: rgba($blue-normal, .07);
+        background-color: $blue-50;
+        color: $blue-600;
+        border-color: $blue-600;
+
+        svg {
+          fill: $blue-600;
+        }
       }
 
       svg {
-        fill: $blue-normal;
+        fill: $blue-500;
       }
     }
 

app/controllers/concerns/issuable_collections.rb

@@ -40,7 +40,7 @@ module IssuableCollections
   end
 
   def issues_collection
-    issues_finder.execute.preload(:project, :author, :assignee, :labels, :milestone, project: :namespace)
+    issues_finder.execute.preload(:project, :author, :labels, :milestone, project: :namespace)
   end
 
   def merge_requests_collection

app/controllers/groups/analytics_controller.rb

@@ -4,7 +4,7 @@ class Groups::AnalyticsController < Groups::ApplicationController
   layout 'group'
 
   def show
-    @users = @group.users
+    @users = @group.users.select(:id, :name, :username)
     @start_date = params[:start_date] || Date.today - 1.week
     @events = Event.contributions
       .where("created_at > ?", @start_date)
@@ -12,16 +12,21 @@ class Groups::AnalyticsController < Groups::ApplicationController
 
     @stats = {}
 
-    @stats[:merge_requests] = @users.map do |user|
-      @events.merge_requests.created.where(author_id: user).count
-    end
+    @stats[:total_events] = count_by_user(@events.totals_by_author)
+    @stats[:push] = count_by_user(@events.code_push.totals_by_author)
+    @stats[:merge_requests_created] = count_by_user(@events.merge_requests.created.totals_by_author)
+    @stats[:merge_requests_merged] = count_by_user(@events.merge_requests.merged.totals_by_author)
+    @stats[:issues_created] = count_by_user(@events.issues.created.totals_by_author)
+    @stats[:issues_closed] = count_by_user(@events.issues.closed.totals_by_author)
+  end
+
+  private
 
-    @stats[:issues] = @users.map do |user|
-      @events.issues.closed.where(author_id: user).count
-    end
+  def count_by_user(data)
+    user_ids.map { |id| data.fetch(id, 0) }
+  end
 
-    @stats[:push] = @users.map do |user|
-      @events.code_push.where(author_id: user).count
-    end
+  def user_ids
+    @user_ids ||= @users.map(&:id)
   end
 end

app/controllers/projects/boards/issues_controller.rb

@@ -82,7 +82,7 @@ module Projects
           labels: true,
           only: [:id, :iid, :title, :confidential, :due_date, :relative_position],
           include: {
-            assignee: { only: [:id, :name, :username], methods: [:avatar_url] },
+            assignees: { only: [:id, :name, :username], methods: [:avatar_url] },
             milestone: { only: [:id, :title] }
           },
           user: current_user

app/controllers/projects/issues_controller.rb

@@ -65,7 +65,7 @@ class Projects::IssuesController < Projects::ApplicationController
 
   def new
     params[:issue] ||= ActionController::Parameters.new(
-      assignee_id: ""
+      assignee_ids: ""
     )
     build_params = issue_params.merge(
       merge_request_to_resolve_discussions_of: params[:merge_request_to_resolve_discussions_of],

app/finders/issues_finder.rb

@@ -26,17 +26,31 @@ class IssuesFinder < IssuableFinder
     IssuesFinder.not_restricted_by_confidentiality(current_user)
   end
 
+  def by_assignee(items)
+    if assignee
+      items = items.where("issue_assignees.user_id = ?", assignee.id)
+    elsif no_assignee?
+      items = items.where("issue_assignees.user_id is NULL")
+    elsif assignee_id? || assignee_username? # assignee not found
+      items = items.none
+    end
+
+    items
+  end
+
   def self.not_restricted_by_confidentiality(user)
-    return Issue.where('issues.confidential IS NULL OR issues.confidential IS FALSE') if user.blank?
+    issues = Issue.with_assignees
+
+    return issues.where('issues.confidential IS NULL OR issues.confidential IS FALSE') if user.blank?
 
-    return Issue.all if user.admin_or_auditor?
+    return issues.all if user.admin_or_auditor?
 
-    Issue.where('
+    issues.where('
       issues.confidential IS NULL
       OR issues.confidential IS FALSE
       OR (issues.confidential = TRUE
         AND (issues.author_id = :user_id
-          OR issues.assignee_id = :user_id
+          OR issue_assignees.user_id = :user_id
           OR issues.project_id IN(:project_ids)))',
       user_id: user.id,
       project_ids: user.authorized_projects(Gitlab::Access::REPORTER).select(:id))

app/mailers/emails/issues.rb

@@ -11,10 +11,12 @@ module Emails
       mail_answer_thread(@issue, issue_thread_options(updated_by_user_id, recipient_id))
     end
 
-    def reassigned_issue_email(recipient_id, issue_id, previous_assignee_id, updated_by_user_id)
+    def reassigned_issue_email(recipient_id, issue_id, previous_assignee_ids, updated_by_user_id)
       setup_issue_mail(issue_id, recipient_id)
 
-      @previous_assignee = User.find_by(id: previous_assignee_id) if previous_assignee_id
+      @previous_assignees = []
+      @previous_assignees = User.where(id: previous_assignee_ids) if previous_assignee_ids.any?
+
       mail_answer_thread(@issue, issue_thread_options(updated_by_user_id, recipient_id))
     end
 

app/models/concerns/issuable.rb

@@ -25,7 +25,6 @@ module Issuable
     cache_markdown_field :description
 
     belongs_to :author, class_name: "User"
-    belongs_to :assignee, class_name: "User"
     belongs_to :updated_by, class_name: "User"
     belongs_to :milestone
     has_many :notes, as: :noteable, inverse_of: :noteable, dependent: :destroy do
@@ -94,7 +93,6 @@ module Issuable
     attr_mentionable :description
 
     participant :author
-    participant :assignee
     participant :notes_with_associations
 
     strip_attributes :title
@@ -285,7 +283,11 @@ module Issuable
       # DEPRECATED
       repository: project.hook_attrs.slice(:name, :url, :description, :homepage)
     }
-    hook_data[:assignee] = assignee.hook_attrs if assignee
+    if self.is_a?(Issue)
+      hook_data[:assignees] = assignees.map(&:hook_attrs) if assignees.any?
+    else
+      hook_data[:assignee] = assignee.hook_attrs if assignee
+    end
 
     hook_data
   end
@@ -319,14 +321,6 @@ module Issuable
     @human_class_name ||= self.class.name.titleize.downcase
   end
 
-  # Returns a Hash of attributes to be used for Twitter card metadata
-  def card_attributes
-    {
-      'Author'   => author.try(:name),
-      'Assignee' => assignee.try(:name)
-    }
-  end
-
   def notes_with_associations
     # If A has_many Bs, and B has_many Cs, and you do
     # `A.includes(b: :c).each { |a| a.b.includes(:c) }`, sadly ActiveRecord
@@ -358,11 +352,6 @@ module Issuable
     false
   end
 
-  def assignee_or_author?(user)
-    # We're comparing IDs here so we don't need to load any associations.
-    author_id == user.id || assignee_id == user.id
-  end
-
   def record_metrics
     metrics = self.metrics || create_metrics
     metrics.record!

app/models/event.rb

@@ -46,6 +46,7 @@ class Event < ActiveRecord::Base
   scope :created, -> { where(action: CREATED) }
   scope :closed, -> { where(action: CLOSED) }
   scope :merged, -> { where(action: MERGED) }
+  scope :totals_by_author, -> { group(:author_id).count }
 
   class << self
     # Update Gitlab::ContributionsCalendar#activity_dates if this changes

app/models/issue.rb

@@ -29,11 +29,14 @@ class Issue < ActiveRecord::Base
 
   has_many :merge_requests_closing_issues, class_name: 'MergeRequestsClosingIssues', dependent: :delete_all
 
+  has_and_belongs_to_many :assignees, class_name: "User", join_table: :issue_assignees
+
   validates :project, presence: true
 
-  scope :cared, ->(user) { where(assignee_id: user) }
+  scope :cared, ->(user) { with_assignees.where("issue_assignees.user_id IN(?)", user.id) }
   scope :open_for, ->(user) { opened.assigned_to(user) }
   scope :in_projects, ->(project_ids) { where(project_id: project_ids) }
+  scope :with_assignees, -> { joins('LEFT JOIN issue_assignees ON issue_id = issues.id') }
 
   scope :without_due_date, -> { where(due_date: nil) }
   scope :due_before, ->(date) { where('issues.due_date < ?', date) }
@@ -51,6 +54,8 @@ class Issue < ActiveRecord::Base
   attr_spammable :title, spam_title: true
   attr_spammable :description, spam_description: true
 
+  participant :assignees
+
   state_machine :state, initial: :opened do
     event :close do
       transition [:reopened, :opened] => :closed
@@ -127,6 +132,28 @@ class Issue < ActiveRecord::Base
               "id DESC")
   end
 
+  # Returns a Hash of attributes to be used for Twitter card metadata
+  def card_attributes
+    {
+      'Author'   => author.try(:name),
+      'Assignee' => assignee_list
+    }
+  end
+
+  def assignee_or_author?(user)
+    author_id == user.id || assignees.exists?(user.id)
+  end
+
+  def assignee_list
+    assignees.map(&:name).to_sentence
+  end
+
+  # TODO: This method will help us to find some silent failures.
+  # We should remove it before merging to master
+  def assignee_id
+    raise "assignee_id is deprecated"
+  end
+
   # `from` argument can be a Namespace or Project.
   def to_reference(from = nil, full: false)
     reference = "#{self.class.reference_prefix}#{iid}"
@@ -261,7 +288,7 @@ class Issue < ActiveRecord::Base
       true
     elsif confidential?
       author == user ||
-        assignee == user ||
+        assignees.include?(user) ||
         project.team.member?(user, Gitlab::Access::REPORTER)
     else
       project.public? ||

app/models/license.rb

@@ -2,7 +2,7 @@ class License < ActiveRecord::Base
   include ActionView::Helpers::NumberHelper
 
   validate :valid_license
-  validate :active_user_count, if: :new_record?, unless: :validate_with_trueup?
+  validate :check_users_limit, if: :new_record?, unless: :validate_with_trueup?
   validate :check_trueup, unless: :persisted?, if: :validate_with_trueup?
   validate :not_expired, unless: :persisted?
 
@@ -99,6 +99,10 @@ class License < ActiveRecord::Base
     restricted_attr(:previous_user_count)
   end
 
+  def current_active_users_count
+    @current_active_users_count ||= User.active.count
+  end
+
   def validate_with_trueup?
     [restricted_attr(:trueup_quantity),
      restricted_attr(:trueup_from),
@@ -127,37 +131,41 @@ class License < ActiveRecord::Base
     self.errors.add(:base, "The license key is invalid. Make sure it is exactly as you received it from GitLab Inc.")
   end
 
-  def historical_max(from, to)
+  def historical_max(from = nil, to = nil)
+    from ||= starts_at - 1.year
+    to   ||= starts_at
+
     HistoricalData.during(from..to).maximum(:active_user_count) || 0
   end
 
-  def active_user_count
+  def check_users_limit
     return unless restricted_user_count
 
-    historical_user_count = historical_max((starts_at - 1.year), starts_at)
-    overage               = historical_user_count - restricted_user_count
-
-    return if historical_user_count <= restricted_user_count
+    if previous_user_count && (historical_max <= previous_user_count)
+      return if restricted_user_count >= current_active_users_count
+    else
+      return if restricted_user_count >= historical_max
+    end
 
-    add_limit_error(user_count: historical_user_count, restricted_user_count: restricted_user_count, overage: overage)
+    overage = historical_max - restricted_user_count
+    add_limit_error(user_count: historical_max, restricted_user_count: restricted_user_count, overage: overage)
   end
 
   def check_trueup
     trueup_qty          = restrictions[:trueup_quantity]
     trueup_from         = Date.parse(restrictions[:trueup_from]) rescue (starts_at - 1.year)
     trueup_to           = Date.parse(restrictions[:trueup_to]) rescue starts_at
-    active_user_count   = User.active.count
     max_historical      = historical_max(trueup_from, trueup_to)
-    overage             = active_user_count - restricted_user_count
+    overage             = current_active_users_count - restricted_user_count
     expected_trueup_qty = if previous_user_count
                             max_historical - previous_user_count
                           else
-                            max_historical - active_user_count
+                            max_historical - current_active_users_count
                           end
 
     if trueup_qty >= expected_trueup_qty
-      if restricted_user_count < active_user_count
-        add_limit_error(trueup: true, user_count: active_user_count, restricted_user_count: restricted_user_count, overage: overage)
+      if restricted_user_count < current_active_users_count
+        add_limit_error(trueup: true, user_count: current_active_users_count, restricted_user_count: restricted_user_count, overage: overage)
       end
     else
       message = "You have applied a True-up for #{trueup_qty} #{"user".pluralize(trueup_qty)} "

app/models/merge_request.rb

@@ -22,6 +22,8 @@ class MergeRequest < ActiveRecord::Base
 
   has_many :merge_requests_closing_issues, class_name: 'MergeRequestsClosingIssues', dependent: :delete_all
 
+  belongs_to :assignee, class_name: "User"
+
   serialize :merge_params, Hash
 
   after_create :ensure_merge_request_diff, unless: :importing?
@@ -121,6 +123,7 @@ class MergeRequest < ActiveRecord::Base
   scope :references_project, -> { references(:target_project) }
 
   participant :approvers_left
+  participant :assignee
 
   after_save :keep_around_commit
 
@@ -182,6 +185,23 @@ class MergeRequest < ActiveRecord::Base
     work_in_progress?(title) ? title : "WIP: #{title}"
   end
 
+  # Returns a Hash of attributes to be used for Twitter card metadata
+  def card_attributes
+    {
+      'Author'   => author.try(:name),
+      'Assignee' => assignee.try(:name)
+    }
+  end
+
+  # This method is needed for compatibility with issues
+  def assignees
+    [assignee]
+  end
+
+  def assignee_or_author?(user)
+    author_id == user.id || assignee_id == user.id
+  end
+
   # `from` argument can be a Namespace or Project.
   def to_reference(from = nil, full: false)
     reference = "#{self.class.reference_prefix}#{iid}"

app/serializers/issuable_entity.rb

 class IssuableEntity < Grape::Entity
   expose :id
   expose :iid
-  expose :assignee_id
-  expose :assignees, using: UserEntity
   expose :author_id
   expose :description
   expose :lock_version
@@ -18,4 +16,4 @@ class IssuableEntity < Grape::Entity
   expose :total_time_spent
   expose :human_time_estimate
   expose :human_total_time_spent
-end
+end
\ No newline at end of file

app/serializers/issue_entity.rb

 class IssueEntity < IssuableEntity
   expose :branch_name
   expose :confidential
+  expose :assignee_ids
   expose :due_date
   expose :moved_to_id
   expose :project_id

app/serializers/merge_request_entity.rb

 class MergeRequestEntity < IssuableEntity
   expose :approvals_before_merge
+  expose :assignee_id
   expose :in_progress_merge_commit_sha
   expose :locked_at
   expose :merge_commit_sha

app/services/issuable_base_service.rb

 class IssuableBaseService < BaseService
   private
 
-  def create_assignee_note(issuable)
-    SystemNoteService.change_assignee(
-      issuable, issuable.project, current_user, issuable.assignee)
-  end
-
   def create_milestone_note(issuable)
     SystemNoteService.change_milestone(
       issuable, issuable.project, current_user, issuable.milestone)
@@ -53,7 +48,13 @@ class IssuableBaseService < BaseService
       params.delete(:add_label_ids)
       params.delete(:remove_label_ids)
       params.delete(:label_ids)
-      params.delete(:assignee_id)
+
+      if issuable.is_a?(Issue)
+        params.delete(:assignee_ids)
+      else
+        params.delete(:assignee_id)
+      end
+
       params.delete(:due_date)
     end
 
@@ -77,7 +78,7 @@ class IssuableBaseService < BaseService
   def assignee_can_read?(issuable, assignee_id)
     new_assignee = User.find_by_id(assignee_id)
 
-    return false unless new_assignee.present?
+    return false unless new_assignee
 
     ability_name = :"read_#{issuable.to_ability_name}"
     resource     = issuable.persisted? ? issuable : project
@@ -207,6 +208,7 @@ class IssuableBaseService < BaseService
     filter_params(issuable)
     old_labels = issuable.labels.to_a
     old_mentioned_users = issuable.mentioned_users.to_a
+    old_assignees = issuable.assignees.to_a
 
     label_ids = process_label_ids(params, existing_label_ids: issuable.label_ids)
     params[:label_ids] = label_ids if labels_changing?(issuable.label_ids, label_ids)
@@ -222,7 +224,13 @@ class IssuableBaseService < BaseService
           handle_common_system_notes(issuable, old_labels: old_labels)
         end
 
-        handle_changes(issuable, old_labels: old_labels, old_mentioned_users: old_mentioned_users)
+        handle_changes(
+          issuable,
+          old_labels: old_labels,
+          old_mentioned_users: old_mentioned_users,
+          old_assignees: old_assignees
+        )
+
         after_update(issuable)
         issuable.create_new_cross_references!(current_user)
         execute_hooks(issuable, 'update')

app/services/issues/base_service.rb

@@ -9,11 +9,28 @@ module Issues
 
     private
 
+    def create_assignee_note(issue)
+      SystemNoteService.change_issue_assignees(
+        issue, issue.project, current_user, issue.assignees)
+    end
+
     def execute_hooks(issue, action = 'open')
       issue_data  = hook_data(issue, action)
       hooks_scope = issue.confidential? ? :confidential_issue_hooks : :issue_hooks
       issue.project.execute_hooks(issue_data, hooks_scope)
       issue.project.execute_services(issue_data, hooks_scope)
     end
+
+    def filter_assignee(issuable)
+      return if params[:assignee_ids].blank?
+
+      assignee_ids = params[:assignee_ids].split(',').map(&:strip)
+
+      if assignee_ids == [ IssuableFinder::NONE ]
+        params[:assignee_ids] = ""
+      else
+        params.delete(:assignee_ids) unless assignee_ids.all?{ |assignee_id| assignee_can_read?(issuable, assignee_id)}
+      end
+    end
   end
 end

app/services/issues/export_csv_service.rb

@@ -21,7 +21,7 @@ module Issues
 
     def csv_builder
       @csv_builder ||=
-        CsvBuilder.new(@issues.includes(:author, :assignee), header_to_value_hash)
+        CsvBuilder.new(@issues.includes(:author), header_to_value_hash)
     end
 
     private
@@ -35,8 +35,8 @@ module Issues
        'Description' => 'description',
        'Author' => 'author_name',
        'Author Username' => -> (issue) { issue.author&.username },
-       'Assignee' => 'assignee_name',
-       'Assignee Username' => -> (issue) { issue.assignee&.username },
+       'Assignee' => -> (issue) { issue.assignees.pluck(:name).join(', ') },
+       'Assignee Username' => -> (issue) { issue.assignees.pluck(:username).join(', ') },
        'Confidential' => -> (issue) { issue.confidential? ? 'Yes' : 'No' },
        'Due Date' => -> (issue) { issue.due_date&.to_s(:csv) },
        'Created At (UTC)' => -> (issue) { issue.created_at&.to_s(:csv) },

app/services/issues/update_service.rb

@@ -12,7 +12,11 @@ module Issues
       spam_check(issue, current_user)
     end
 
-    def handle_changes(issue, old_labels: [], old_mentioned_users: [])
+    def handle_changes(issue, options)
+      old_labels = options[:old_labels] || []
+      old_mentioned_users = options[:old_mentioned_users] || []
+      old_assignees = options[:old_assignees] || []
+
       if has_changes?(issue, old_labels: old_labels)
         todo_service.mark_pending_todos_as_done(issue, current_user)
       end
@@ -26,9 +30,9 @@ module Issues
         create_milestone_note(issue)
       end
 
-      if issue.previous_changes.include?('assignee_id')
+      if issue.previous_changes.include?('assignee_ids')
         create_assignee_note(issue)
-        notification_service.reassigned_issue(issue, current_user)
+        notification_service.reassigned_issue(issue, current_user, old_assignees)
         todo_service.reassigned_issue(issue, current_user)
       end
 

app/services/merge_requests/assign_issues_service.rb

@@ -4,7 +4,7 @@ module MergeRequests
       @assignable_issues ||= begin
         if current_user == merge_request.author
           closes_issues.select do |issue|
-            !issue.is_a?(ExternalIssue) && !issue.assignee_id? && can?(current_user, :admin_issue, issue)
+            !issue.is_a?(ExternalIssue) && !issue.assignees.any? && can?(current_user, :admin_issue, issue)
           end
         else
           []
@@ -14,7 +14,7 @@ module MergeRequests
 
     def execute
       assignable_issues.each do |issue|
-        Issues::UpdateService.new(issue.project, current_user, assignee_id: current_user.id).execute(issue)
+        Issues::UpdateService.new(issue.project, current_user, assignee_ids: current_user.id.to_s).execute(issue)
       end
 
       {

app/services/merge_requests/base_service.rb

@@ -38,6 +38,11 @@ module MergeRequests
 
     private
 
+    def create_assignee_note(merge_request)
+      SystemNoteService.change_assignee(
+        merge_request, merge_request.project, current_user, merge_request.assignee)
+    end
+
     # Returns all origin and fork merge requests from `@project` satisfying passed arguments.
     def merge_requests_for(source_branch, mr_states: [:opened])
       MergeRequest

app/services/merge_requests/update_service.rb

@@ -31,7 +31,10 @@ module MergeRequests
       merge_request
     end
 
-    def handle_changes(merge_request, old_labels: [], old_mentioned_users: [])
+    def handle_changes(merge_request, options)
+      old_labels = options[:old_labels] || []
+      old_mentioned_users = options[:old_mentioned_users] || []
+
       if has_changes?(merge_request, old_labels: old_labels)
         todo_service.mark_pending_todos_as_done(merge_request, current_user)
       end

app/services/notification_recipient_service.rb

@@ -3,11 +3,12 @@
 #
 class NotificationRecipientService
   attr_reader :project
-  
+
   def initialize(project)
     @project = project
   end
 
+  # TODO: refactor this: previous_assignee argument can be a user object or an array which is not really nice
   def build_recipients(target, current_user, action: nil, previous_assignee: nil, skip_current_user: true)
     custom_action = build_custom_key(action, target)
 
@@ -23,9 +24,13 @@ class NotificationRecipientService
     # Re-assign is considered as a mention of the new assignee so we add the
     # new assignee to the list of recipients after we rejected users with
     # the "on mention" notification level
-    if [:reassign_merge_request, :reassign_issue].include?(custom_action)
+    case custom_action
+    when :reassign_merge_request
       recipients << previous_assignee if previous_assignee
       recipients << target.assignee
+    when :reassign_issue
+      recipients.concat(previous_assignee) if previous_assignee.any?
+      recipients.concat(target.assignees)
     end
 
     recipients = reject_muted_users(recipients)

app/services/notification_service.rb

@@ -66,8 +66,23 @@ class NotificationService
   #  * issue new assignee if their notification level is not Disabled
   #  * users with custom level checked with "reassign issue"
   #
-  def reassigned_issue(issue, current_user)
-    reassign_resource_email(issue, issue.project, current_user, :reassigned_issue_email)
+  def reassigned_issue(issue, current_user, previous_assignees = [])
+    recipients = NotificationRecipientService.new(issue.project).build_recipients(
+      issue,
+      current_user,
+      action: "reassign",
+      previous_assignee: previous_assignees
+    )
+
+    recipients.each do |recipient|
+      mailer.send(
+        :reassigned_issue_email,
+        recipient.id,
+        issue.id,
+        previous_assignees.map(&:id),
+        current_user.id
+      ).deliver_later
+    end
   end
 
   # When we add labels to an issue we should send an email to:
@@ -407,10 +422,10 @@ class NotificationService
   end
 
   def previous_record(object, attribute)
-    if object && attribute
-      if object.previous_changes.include?(attribute)
-        object.previous_changes[attribute].first
-      end
+    return unless object && attribute
+
+    if object.previous_changes.include?(attribute)
+      object.previous_changes[attribute].first
     end
   end
 end

app/services/system_note_service.rb

@@ -49,6 +49,42 @@ module SystemNoteService
     create_note(noteable: noteable, project: project, author: author, note: body)
   end
 
+  # Called when the assignees of an Issue is changed or removed
+  #
+  # issue - Issue object
+  # project  - Project owning noteable
+  # author   - User performing the change
+  # assignees - User being assigned, or nil
+  #
+  # Example Note text:
+  #
+  #   "removed all assignees"
+  #
+  #   "assigned to @user1 additionally to @user2"
+  #
+  #   "assigned to @user1, @user2 and @user3 and unassigned from @user4 and @user5"
+  #
+  #   "assigned to @user1 and @user2"
+  #
+  # Returns the created Note object
+  def change_issue_assignees(issue, project, author, assignees)
+    # TODO: basic implementation, should be improved before merging the MR
+    body =
+      if issue.assignees.any? && assignees.any?
+        unassigned_users = issue.assignees - assignees
+        added_users = assignees - issue.assignees
+
+        "assigned to #{added_users.map(&:to_reference).to_sentence} and unassigned #{unassigned_users.map(&:to_reference).to_sentence}"
+      elsif issue.assignees.any?
+        "removed all assignees"
+      elsif assignees.any?
+        "assigned to #{assignees.map(&:to_reference).to_sentence}"
+      end
+
+    create_note(noteable: issue, project: project, author: author, note: body)
+  end
+
+
   # Called when one or more labels on a Noteable are added and/or removed
   #
   # noteable       - Noteable object

app/services/todo_service.rb

@@ -264,13 +264,13 @@ class TodoService
   end
 
   def create_assignment_todo(issuable, author)
-    if issuable.assignee
+    if issuable.assignees.any?
       attributes = attributes_for_todo(issuable.project, issuable, author, Todo::ASSIGNED)
-      create_todos(issuable.assignee, attributes)
+      create_todos(issuable.assignees, attributes)
     end
   end
 
-  def create_mention_todos(project, target, author, note = nil)
+    def create_mention_todos(project, target, author, note = nil)
     # Create Todos for directly addressed users
     directly_addressed_users = filter_directly_addressed_users(project, note || target, author)
     attributes = attributes_for_todo(project, target, author, Todo::DIRECTLY_ADDRESSED, note)

app/views/groups/analytics/show.html.haml

@@ -60,7 +60,7 @@
   .col-md-8
     %div
       %p.light Merge requests created per group member
-      %canvas#merge_requests{ height: 250 }
+      %canvas#merge_requests_created{ height: 250 }
 
 %h3 Issues
 
@@ -77,7 +77,7 @@
   .col-md-8
     %div
       %p.light Issues closed per group member
-      %canvas#issues{ height: 250 }
+      %canvas#issues_closed{ height: 250 }
 
 .gray-content-block
   .oneline
@@ -109,21 +109,21 @@
           Total Contributions
           = icon('sort')
     %tbody
-      - @users.each do |user|
+      - @users.each_with_index do |user, index|
         %tr
           %td
             %strong
               = link_to user.name, user
-          %td= @events.code_push.where(author_id: user).count
-          %td= @events.issues.created.where(author_id: user).count
-          %td= @events.issues.closed.where(author_id: user).count
-          %td= @events.merge_requests.created.where(author_id: user).count
-          %td= @events.merge_requests.merged.where(author_id: user).count
-          %td= @events.where(author_id: user).count
+          %td= @stats[:push][index]
+          %td= @stats[:issues_created][index]
+          %td= @stats[:issues_closed][index]
+          %td= @stats[:merge_requests_created][index]
+          %td= @stats[:merge_requests_merged][index]
+          %td= @stats[:total_events][index]
 
 
 
-- [:push, :issues, :merge_requests].each do |scope|
+- [:push, :issues_closed, :merge_requests_created].each do |scope|
   :javascript
     var data = {
       labels : #{@users.map(&:name).to_json},

app/views/issues/_issue.atom.builder

@@ -23,10 +23,12 @@ xml.entry do
     end
   end
 
-  if issue.assignee
-    xml.assignee do
-      xml.name issue.assignee.name
-      xml.email issue.assignee_public_email
+  if issue.assignees.any?
+    xml.assignees do
+      issue.assignees.each do |assignee|
+        xml.name ssignee.name
+        xml.email assignee.assignee_public_email
+      end
     end
   end
 end

app/views/notify/_reassigned_issuable_email.text.erb

-Reassigned <%= issuable.class.model_name.human.titleize %> <%= issuable.iid %>
+Reassigned Issue <%= @issue.iid %>
 
-<%= url_for([issuable.project.namespace.becomes(Namespace), issuable.project, issuable, { only_path: false }]) %>
+<%= url_for([@issue.project.namespace.becomes(Namespace), @issue.project, @issue, { only_path: false }]) %>
 
-Assignee changed <%= "from #{@previous_assignee.name}" if @previous_assignee -%>
- to <%= "#{issuable.assignee_id ? issuable.assignee_name : 'Unassigned'}" %>
+Assignee changed <%= "from #{@previous_assignees.map(&:name).to_sentence}" if @previous_assignees.any? -%>
+ to <%= "#{@issue.assignees.any? ? @issue.assignee_list : 'Unassigned'}" %>

app/views/notify/new_issue_email.html.haml

@@ -4,6 +4,6 @@
 - if @issue.description
   = markdown(@issue.description, pipeline: :email, author: @issue.author)
 
-- if @issue.assignee_id.present?
+- if @issue.assignees.any?
   %p
-    Assignee: #{@issue.assignee_name}
+    Assignee: #{@issue.assignee_list}

app/views/notify/new_issue_email.text.erb

@@ -2,6 +2,6 @@ New Issue was created.
 
 Issue <%= @issue.iid %>: <%= url_for(namespace_project_issue_url(@issue.project.namespace, @issue.project, @issue)) %>
 Author:    <%= @issue.author_name %>
-Assignee:  <%= @issue.assignee_name %>
+Assignee:  <%= @issue.assignee_list %>
 
 <%= @issue.description %>

app/views/notify/new_mention_in_issue_email.html.haml

@@ -7,6 +7,6 @@
 - if @issue.description
   = markdown(@issue.description, pipeline: :email, author: @issue.author)
 
-- if @issue.assignee_id.present?
+- if @issue.assignees.any?
   %p
-    Assignee: #{@issue.assignee_name}
+    Assignee: #{@issue.assignee_list}

app/views/notify/new_mention_in_issue_email.text.erb

@@ -2,6 +2,6 @@ You have been mentioned in an issue.
 
 Issue <%= @issue.iid %>: <%= url_for(namespace_project_issue_url(@issue.project.namespace, @issue.project, @issue)) %>
 Author:    <%= @issue.author_name %>
-Assignee:  <%= @issue.assignee_name %>
+Assignee:  <%= @issue.assignee_list %>
 
 <%= @issue.description %>

app/views/notify/reassigned_issue_email.html.haml

-= render 'reassigned_issuable_email', issuable: @issue
+%p
+  Assignee changed
+  - if @previous_assignees.any?
+    from
+    %strong= @previous_assignees.map(&:name).to_sentence
+  to
+  - if @issue.assignees.any?
+    %strong= @issue.assignee_list
+  - else
+    %strong Unassigned
+

app/views/notify/reassigned_merge_request_email.text.erb

-<%= render 'reassigned_issuable_email', issuable: @merge_request %>
+Reassigned Merge Request <%= @merge_request.iid %>
+
+<%= url_for([@merge_request.project.namespace.becomes(Namespace), @merge_request.project, @merge_request, { only_path: false }]) %>
+
+Assignee changed <%= "from #{@previous_assignee.name}" if @previous_assignee -%>
+ to <%= "#{@merge_request.assignee_id ? @merge_request.assignee_name : 'Unassigned'}" %>

app/views/projects/issues/_issue.html.haml

@@ -13,7 +13,7 @@
             %li
               CLOSED
 
-          - if issue.assignee
+          - if issue.assignees.any?
             %li
               = render 'shared/issuable/assignees', project: @project, issue: issue
 
@@ -48,4 +48,4 @@
             = issue.weight
 
         .pull-right.issue-updated-at
-          %span updated #{time_ago_with_tooltip(issue.updated_at, placement: 'bottom', html_class: 'issue_update_ago')}
+          %span updated #{time_ago_with_tooltip(issue.updated_at, placement: 'bottom', html_class: 'issue_update_ago')}
\ No newline at end of file

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

@@ -22,36 +22,8 @@
           = icon('spin spinner', class: 'hidden js-issuable-todo-loading', 'aria-hidden': 'true')
 
     = form_for [@project.namespace.becomes(Namespace), @project, issuable], remote: true, format: :json, html: { class: 'issuable-context-form inline-update js-issuable-update' } do |f|
-      .block.assignee
-        .sidebar-collapsed-icon.sidebar-collapsed-user{ data: { toggle: "tooltip", placement: "left", container: "body" }, title: (issuable.assignee.name if issuable.assignee) }
-          - if issuable.assignee
-            = link_to_member(@project, issuable.assignee, size: 24)
-          - else
-            = icon('user', 'aria-hidden': 'true')
-        .title.hide-collapsed
-          Assignee
-          = icon('spinner spin', class: 'hidden block-loading', 'aria-hidden': 'true')
-          - if can_edit_issuable
-            = link_to 'Edit', '#', class: 'edit-link pull-right'
-        .value.hide-collapsed
-          - if issuable.assignee
-            = link_to_member(@project, issuable.assignee, size: 32, extra_class: 'bold') do
-              - if issuable.instance_of?(MergeRequest) && !issuable.can_be_merged_by?(issuable.assignee)
-                %span.pull-right.cannot-be-merged{ data: { toggle: 'tooltip', placement: 'left' }, title: 'Not allowed to merge' }
-                  = icon('exclamation-triangle', 'aria-hidden': 'true')
-              %span.username
-                = issuable.assignee.to_reference
-          - else
-            %span.assign-yourself.no-value
-              No assignee
-              - if can_edit_issuable
-                \-
-                %a.js-assign-yourself{ href: '#' }
-                  assign yourself
 
-        .selectbox.hide-collapsed
-          = f.hidden_field 'assignee_id', value: issuable.assignee_id, id: 'issue_assignee_id'
-          = dropdown_tag('Select assignee', options: { toggle_class: 'js-user-search js-author-search', title: 'Assign to', filter: true, dropdown_class: 'dropdown-menu-user dropdown-menu-selectable dropdown-menu-author', placeholder: 'Search users', data: { first_user: (current_user.username if current_user), current_user: true, project_id: (@project.id if @project), author_id: issuable.author_id, field_name: "#{issuable.to_ability_name}[assignee_id]", issue_update: issuable_json_path(issuable), ability_name: issuable.to_ability_name, null_user: true } })
+      = render "shared/issuable/form/#{issuable.model_name.singular}_assignee", can_edit_issuable: can_edit_issuable, issuable: issuable, f: f
 
       .block.milestone
         .sidebar-collapsed-icon
@@ -162,11 +134,11 @@
             = icon('spinner spin', class: 'block-loading')
             - if can?(current_user, :"admin_#{issuable.to_ability_name}", @project)
               = link_to 'Edit', '#', class: 'edit-link pull-right'
-          .value.bold.hide-collapsed
+          .value.hide-collapsed
             - if issuable.weight
-              = issuable.weight
+              %strong= issuable.weight
             - else
-              .light None
+              %span.no-value None
           .selectbox.hide-collapsed
             = weight_dropdown_tag(issuable, title: 'Change weight', data: { field_name: 'weight', issue_update: "#{issuable_json_path(issuable)}", ability_name: "#{issuable.to_ability_name}" }) do
               %ul

app/views/shared/issuable/form/_issue_assignee.html.haml

+- issue = issuable
+.block.assignee
+  .sidebar-collapsed-icon.sidebar-collapsed-user{ data: { toggle: "tooltip", placement: "left", container: "body" }, title: (issuable.assignee_list) }
+    - if issue.assignees.any?
+      - issue.assignees.each do |assignee|
+        = link_to_member(@project, assignee, size: 24)
+    - else
+      = icon('user', 'aria-hidden': 'true')
+  .title.hide-collapsed
+    Assignee
+    = icon('spinner spin', class: 'hidden block-loading', 'aria-hidden': 'true')
+    - if can_edit_issuable
+      = link_to 'Edit', '#', class: 'edit-link pull-right'
+  .value.hide-collapsed
+    - if issue.assignees.any?
+      - issue.assignees.each do |assignee|
+        = link_to_member(@project, assignee, size: 32, extra_class: 'bold') do
+          %span.username
+            = assignee.to_reference
+    - else
+      %span.assign-yourself.no-value
+        No assignee
+        - if can_edit_issuable
+          \-
+          %a.js-assign-yourself{ href: '#' }
+            assign yourself
+
+  .selectbox.hide-collapsed
+    = f.hidden_field 'assignee_ids', value: issuable.assignee_ids, id: 'issue_assignee_ids'
+    = dropdown_tag('Select assignee', options: { toggle_class: 'js-user-search js-author-search', title: 'Assign to', filter: true, dropdown_class: 'dropdown-menu-user dropdown-menu-selectable dropdown-menu-author', placeholder: 'Search users', data: { first_user: (current_user.username if current_user), current_user: true, project_id: (@project.id if @project), author_id: issuable.author_id, field_name: "#{issuable.to_ability_name}[assignee_id]", issue_update: issuable_json_path(issuable), ability_name: issuable.to_ability_name, null_user: true } })

app/views/shared/issuable/form/_merge_request_assignee.html.haml

+- merge_request = issuable
+.block.assignee
+  .sidebar-collapsed-icon.sidebar-collapsed-user{ data: { toggle: "tooltip", placement: "left", container: "body" }, title: (merge_request.assignee.name if merge_request.assignee) }
+    - if merge_request.assignee
+      = link_to_member(@project, merge_request.assignee, size: 24)
+    - else
+      = icon('user', 'aria-hidden': 'true')
+  .title.hide-collapsed
+    Assignee
+    = icon('spinner spin', class: 'hidden block-loading', 'aria-hidden': 'true')
+    - if can_edit_issuable
+      = link_to 'Edit', '#', class: 'edit-link pull-right'
+  .value.hide-collapsed
+    - if merge_request.assignee
+      = link_to_member(@project, merge_request.assignee, size: 32, extra_class: 'bold') do
+        - unless merge_request.can_be_merged_by?(merge_request.assignee)
+          %span.pull-right.cannot-be-merged{ data: { toggle: 'tooltip', placement: 'left' }, title: 'Not allowed to merge' }
+            = icon('exclamation-triangle', 'aria-hidden': 'true')
+        %span.username
+          = merge_request.assignee.to_reference
+    - else
+      %span.assign-yourself.no-value
+        No assignee
+        - if can_edit_issuable
+          \-
+          %a.js-assign-yourself{ href: '#' }
+            assign yourself
+
+  .selectbox.hide-collapsed
+    = f.hidden_field 'assignee_id', value: merge_request.assignee_id, id: 'issue_assignee_id'
+    = dropdown_tag('Select assignee', options: { toggle_class: 'js-user-search js-author-search', title: 'Assign to', filter: true, dropdown_class: 'dropdown-menu-user dropdown-menu-selectable dropdown-menu-author', placeholder: 'Search users', data: { first_user: (current_user.username if current_user), current_user: true, project_id: @project&.id, author_id: merge_request.author_id, field_name: 'merge_request[assignee_id]', issue_update: issuable_json_path(merge_request), ability_name: 'merge_request', null_user: true } })

app/views/shared/issuable/form/_metadata.html.haml

@@ -10,13 +10,24 @@
 .row
   %div{ class: (has_due_date ? "col-lg-6" : "col-sm-12") }
     .form-group.issue-assignee
-      = form.label :assignee_id, "Assignee", class: "control-label #{"col-lg-4" if has_due_date}"
-      .col-sm-10{ class: ("col-lg-8" if has_due_date) }
-        .issuable-form-select-holder
-          = form.hidden_field :assignee_id
-          = dropdown_tag(user_dropdown_label(issuable.assignee_id, "Assignee"), options: { toggle_class: "js-dropdown-keep-input js-user-search js-issuable-form-dropdown js-assignee-search", title: "Select assignee", filter: true, dropdown_class: "dropdown-menu-user dropdown-menu-selectable dropdown-menu-assignee js-filter-submit",
-            placeholder: "Search assignee", data: { first_user: current_user.try(:username), null_user: true, current_user: true, project_id: issuable.project.try(:id), selected: issuable.assignee_id, field_name: "#{issuable.class.model_name.param_key}[assignee_id]", default_label: "Assignee"} })
-        = link_to 'Assign to me', '#', class: "assign-to-me-link #{'hide' if issuable.assignee_id == current_user.id}"
+      - if issuable.is_a?(Issue)
+        = form.label :assignee_ids, "Assignee", class: "control-label #{"col-lg-4" if has_due_date}"
+        .col-sm-10{ class: ("col-lg-8" if has_due_date) }
+          .issuable-form-select-holder
+            = form.hidden_field :assignee_ids
+
+            = dropdown_tag(user_dropdown_label(issuable.assignee_ids, "Assignee"), options: { toggle_class: "js-dropdown-keep-input js-user-search js-issuable-form-dropdown js-assignee-search", title: "Select assignee", filter: true, dropdown_class: "dropdown-menu-user dropdown-menu-selectable dropdown-menu-assignee js-filter-submit",
+              placeholder: "Search assignee", data: { first_user: current_user.try(:username), null_user: true, current_user: true, project_id: issuable.project.try(:id), selected: issuable.assignee_ids, field_name: "#{issuable.class.model_name.param_key}[assignee_ids]", default_label: "Assignee"} })
+          = link_to 'Assign to me', '#', class: "assign-to-me-link #{'hide' if issuable.assignee_ids.split(', ').include?(current_user.id)}"
+      - else
+        = form.label :assignee_id, "Assignee", class: "control-label #{"col-lg-4" if has_due_date}"
+        .col-sm-10{ class: ("col-lg-8" if has_due_date) }
+          .issuable-form-select-holder
+            = form.hidden_field :assignee_id
+
+            = dropdown_tag(user_dropdown_label(issuable.assignee_id, "Assignee"), options: { toggle_class: "js-dropdown-keep-input js-user-search js-issuable-form-dropdown js-assignee-search", title: "Select assignee", filter: true, dropdown_class: "dropdown-menu-user dropdown-menu-selectable dropdown-menu-assignee js-filter-submit",
+              placeholder: "Search assignee", data: { first_user: current_user.try(:username), null_user: true, current_user: true, project_id: issuable.project.try(:id), selected: issuable.assignee_id, field_name: "#{issuable.class.model_name.param_key}[assignee_id]", default_label: "Assignee"} })
+          = link_to 'Assign to me', '#', class: "assign-to-me-link #{'hide' if issuable.assignee_id == current_user.id}"
     .form-group.issue-milestone
       = form.label :milestone_id, "Milestone", class: "control-label #{"col-lg-4" if has_due_date}"
       .col-sm-10{ class: ("col-lg-8" if has_due_date) }

changelogs/unreleased-ee/28614-harmonious-color-palette-ee.yml

+---
+title: Update color palette to a more harmonious and consistent one.
+merge_request: 1500
+author:

changelogs/unreleased-ee/sh-optimize-analytics-controller.yml

+---
+title: Remove N+1 queries for Groups::AnalyticsController
+merge_request:
+author:

changelogs/unreleased/28614-harmonious-color-palette.yml

+---
+title: Update color palette to a more harmonious and consistent one.
+merge_request: 10154
+author:

changelogs/unreleased/add-issue-modal-loading-indicator.yml

+---
+title: Shows loading icon in issue boards modal when changing filters
+merge_request:
+author:

db/fixtures/development/09_issues.rb

@@ -8,7 +8,7 @@ Gitlab::Seeder.quiet do
         description: FFaker::Lorem.sentence,
         state: ['opened', 'closed'].sample,
         milestone: project.milestones.sample,
-        assignee: project.team.users.sample
+        assignees: [project.team.users.sample]
       }
 
       Issues::CreateService.new(project, project.team.users.sample, issue_params).execute

db/migrate/20170320171632_create_issue_assignees_table.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class CreateIssueAssigneesTable < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  # When a migration requires downtime you **must** uncomment the following
+  # constant and define a short and easy to understand explanation as to why the
+  # migration requires downtime.
+  # DOWNTIME_REASON = ''
+
+  # When using the methods "add_concurrent_index" or "add_column_with_default"
+  # you must disable the use of transactions as these methods can not run in an
+  # existing transaction. When using "add_concurrent_index" make sure that this
+  # method is the _only_ method called in the migration, any other changes
+  # should go in a separate migration. This ensures that upon failure _only_ the
+  # index creation fails and can be retried or reverted easily.
+  #
+  # To disable transactions uncomment the following line and remove these
+  # comments:
+  # disable_ddl_transaction!
+
+  def change
+    create_table :issue_assignees do |t|
+      t.references :user, foreign_key: { on_delete: :cascade }, index: true, null: false
+      t.references :issue, foreign_key: { on_delete: :cascade }, null: false
+    end
+
+    add_index :issue_assignees, [:issue_id, :user_id], unique: true
+  end
+end

db/migrate/20170320173259_migrate_assignees.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class MigrateAssignees < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  # When a migration requires downtime you **must** uncomment the following
+  # constant and define a short and easy to understand explanation as to why the
+  # migration requires downtime.
+  # DOWNTIME_REASON = ''
+
+  # When using the methods "add_concurrent_index" or "add_column_with_default"
+  # you must disable the use of transactions as these methods can not run in an
+  # existing transaction. When using "add_concurrent_index" make sure that this
+  # method is the _only_ method called in the migration, any other changes
+  # should go in a separate migration. This ensures that upon failure _only_ the
+  # index creation fails and can be retried or reverted easily.
+  #
+  # To disable transactions uncomment the following line and remove these
+  # comments:
+  # disable_ddl_transaction!
+
+  def up
+    execute <<-EOF
+      INSERT INTO issue_assignees(issue_id, user_id)
+      SELECT id, assignee_id FROM issues WHERE assignee_id IS NOT NULL
+    EOF
+  end
+
+  def down
+    execute <<-EOF
+      DELETE FROM issue_assignees
+    EOF
+  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: 20170317203554) do
+ActiveRecord::Schema.define(version: 20170320173259) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -495,6 +495,14 @@ ActiveRecord::Schema.define(version: 20170317203554) do
 
   add_index "index_statuses", ["project_id"], name: "index_index_statuses_on_project_id", unique: true, using: :btree
 
+  create_table "issue_assignees", force: :cascade do |t|
+    t.integer "user_id", null: false
+    t.integer "issue_id", null: false
+  end
+
+  add_index "issue_assignees", ["issue_id", "user_id"], name: "index_issue_assignees_on_issue_id_and_user_id", unique: true, using: :btree
+  add_index "issue_assignees", ["user_id"], name: "index_issue_assignees_on_user_id", using: :btree
+
   create_table "issue_metrics", force: :cascade do |t|
     t.integer "issue_id", null: false
     t.datetime "first_mentioned_in_commit_at"
@@ -1491,6 +1499,8 @@ ActiveRecord::Schema.define(version: 20170317203554) do
   add_foreign_key "boards", "projects"
   add_foreign_key "chat_teams", "namespaces", on_delete: :cascade
   add_foreign_key "ci_triggers", "users", column: "owner_id", name: "fk_e8e10d1964", on_delete: :cascade
+  add_foreign_key "issue_assignees", "issues", on_delete: :cascade
+  add_foreign_key "issue_assignees", "users", on_delete: :cascade
   add_foreign_key "issue_metrics", "issues", on_delete: :cascade
   add_foreign_key "label_priorities", "labels", on_delete: :cascade
   add_foreign_key "label_priorities", "projects", on_delete: :cascade

lib/banzai/reference_parser/issue_parser.rb

@@ -28,7 +28,7 @@ module Banzai
           nodes,
           Issue.all.includes(
             :author,
-            :assignee,
+            :assignees,
             {
               # These associations are primarily used for checking permissions.
               # Eager loading these ensures we don't end up running dozens of

spec/controllers/dashboard/todos_controller_spec.rb

@@ -16,7 +16,7 @@ describe Dashboard::TodosController do
   describe 'GET #index' do
     context 'when using pagination' do
       let(:last_page) { user.todos.page.total_pages }
-      let!(:issues) { create_list(:issue, 2, project: project, assignee: user) }
+      let!(:issues) { create_list(:issue, 2, project: project, assignees: [user]) }
 
       before do
         issues.each { |issue| todo_service.new_issue(issue, user) }

spec/controllers/groups/analytics_controller_spec.rb

+require 'spec_helper'
+
+describe Groups::AnalyticsController do
+  let(:user) { create(:user) }
+  let(:user2) { create(:user) }
+  let(:user3) { create(:user) }
+  let(:group) { create(:group) }
+  let(:project) { create(:project, group: group) }
+  let(:issue) { create(:issue, project: project) }
+  let(:merge_request) { create(:merge_request, :simple, source_project: project) }
+  let(:push_data) { Gitlab::DataBuilder::Push.build_sample(project, user) }
+
+  def create_event(author, project, target, action)
+    Event.create!(
+      project: project,
+      action: action,
+      target: target,
+      author: author,
+      created_at: Time.now)
+  end
+
+  def create_push_event(author, project)
+    event = create_event(author, project, nil, Event::PUSHED)
+    event.data = push_data
+    event.save
+  end
+
+  before do
+    group.add_owner(user)
+    group.add_user(user2, GroupMember::DEVELOPER)
+    group.add_user(user3, GroupMember::MASTER)
+    sign_in(user)
+
+    create_event(user, project, issue, Event::CLOSED)
+    create_event(user2, project, issue, Event::CLOSED)
+    create_event(user2, project, merge_request, Event::CREATED)
+    create_event(user3, project, merge_request, Event::CREATED)
+    create_push_event(user, project)
+    create_push_event(user3, project)
+  end
+
+  it 'sets instance variables properly' do
+    get :show, group_id: group.path
+
+    expect(controller.instance_variable_get(:@users)).to match_array([user, user2, user3])
+    expect(controller.instance_variable_get(:@events).length).to eq(6)
+    stats = controller.instance_variable_get(:@stats)
+    expect(stats[:total_events]).to eq([2, 2, 2])
+    expect(stats[:merge_requests_merged]).to eq([0, 0, 0])
+    expect(stats[:merge_requests_created]).to eq([1, 1, 0])
+    expect(stats[:issues_closed]).to eq([0, 1, 1])
+    expect(stats[:push]).to eq([1, 0, 1])
+  end
+
+  describe 'with views' do
+    render_views
+
+    it 'avoids a N+1 query in #show' do
+      control_count = ActiveRecord::QueryRecorder.new { get :show, group_id: group.path }.count
+
+      # Clear out controller state to force a refresh of the group
+      controller.instance_variable_set(:@group, nil)
+      user4 = create(:user)
+      group.add_user(user4, GroupMember::DEVELOPER)
+
+      expect { get :show, group_id: group.path }.not_to exceed_query_limit(control_count)
+    end
+  end
+end

spec/controllers/projects/boards/issues_controller_spec.rb

@@ -34,7 +34,7 @@ describe Projects::Boards::IssuesController do
           issue = create(:labeled_issue, project: project, labels: [planning])
           create(:labeled_issue, project: project, labels: [planning])
           create(:labeled_issue, project: project, labels: [development], due_date: Date.tomorrow)
-          create(:labeled_issue, project: project, labels: [development], assignee: johndoe)
+          create(:labeled_issue, project: project, labels: [development], assignees: [johndoe])
           issue.subscribe(johndoe, project)
 
           list_issues user: user, board: board, list: list2

spec/controllers/projects/issues_controller_spec.rb

@@ -336,7 +336,7 @@ describe Projects::IssuesController do
     let(:admin) { create(:admin) }
     let!(:issue) { create(:issue, project: project) }
     let!(:unescaped_parameter_value) { create(:issue, :confidential, project: project, author: author) }
-    let!(:request_forgery_timing_attack) { create(:issue, :confidential, project: project, assignee: assignee) }
+    let!(:request_forgery_timing_attack) { create(:issue, :confidential, project: project, assignees: [assignee]) }
 
     describe 'GET #index' do
       it 'does not list confidential issues for guests' do

spec/controllers/projects/merge_requests_controller_spec.rb

@@ -1329,7 +1329,7 @@ describe Projects::MergeRequestsController do
     end
 
     it 'correctly pluralizes flash message on success' do
-      issue2.update!(assignee: user)
+      issue2.update!(assignees: [user])
 
       post_assign_issues
 

spec/features/atom/dashboard_issues_spec.rb

@@ -32,7 +32,7 @@ describe "Dashboard Issues Feed", feature: true  do
       end
 
       context "issue with basic fields" do
-        let!(:issue2) { create(:issue, author: user, assignee: assignee, project: project2, description: 'test desc') }
+        let!(:issue2) { create(:issue, author: user, assignees: [assignee], project: project2, description: 'test desc') }
 
         it "renders issue fields" do
           visit issues_dashboard_path(:atom, private_token: user.private_token)
@@ -51,7 +51,7 @@ describe "Dashboard Issues Feed", feature: true  do
       context "issue with label and milestone" do
         let!(:milestone1) { create(:milestone, project: project1, title: 'v1') }
         let!(:label1)     { create(:label, project: project1, title: 'label1') }
-        let!(:issue1)     { create(:issue, author: user, assignee: assignee, project: project1, milestone: milestone1) }
+        let!(:issue1)     { create(:issue, author: user, assignees: [assignee], project: project1, milestone: milestone1) }
 
         before do
           issue1.labels << label1

spec/features/atom/issues_spec.rb

@@ -6,7 +6,7 @@ describe 'Issues Feed', feature: true  do
     let!(:assignee) { create(:user, email: 'private2@example.com', public_email: 'public2@example.com') }
     let!(:group)    { create(:group) }
     let!(:project)  { create(:project) }
-    let!(:issue)    { create(:issue, author: user, assignee: assignee, project: project) }
+    let!(:issue)    { create(:issue, author: user, assignees: [assignee], project: project) }
 
     before do
       project.team << [user, :developer]

spec/features/boards/boards_spec.rb

@@ -72,7 +72,7 @@ describe 'Issue Boards', feature: true, js: true do
     let!(:list2) { create(:list, board: board, label: development, position: 1) }
 
     let!(:confidential_issue) { create(:labeled_issue, :confidential, project: project, author: user, labels: [planning], relative_position: 9) }
-    let!(:issue1) { create(:labeled_issue, project: project, assignee: user, labels: [planning], relative_position: 8) }
+    let!(:issue1) { create(:labeled_issue, project: project, assignees: [user], labels: [planning], relative_position: 8) }
     let!(:issue2) { create(:labeled_issue, project: project, author: user2, labels: [planning], relative_position: 7) }
     let!(:issue3) { create(:labeled_issue, project: project, labels: [planning], relative_position: 6) }
     let!(:issue4) { create(:labeled_issue, project: project, labels: [planning], relative_position: 5) }

spec/features/boards/modal_filter_spec.rb

@@ -98,7 +98,7 @@ describe 'Issue Boards add issue modal filtering', :feature, :js do
   end
 
   context 'assignee' do
-    let!(:issue) { create(:issue, project: project, assignee: user2) }
+    let!(:issue) { create(:issue, project: project, assignees: [user2]) }
 
     before do
       project.team << [user2, :developer]

spec/features/boards/sidebar_spec.rb

@@ -11,7 +11,7 @@ describe 'Issue Boards', feature: true, js: true do
   let!(:bug)         { create(:label, project: project, name: 'Bug') }
   let!(:regression)  { create(:label, project: project, name: 'Regression') }
   let!(:stretch)     { create(:label, project: project, name: 'Stretch') }
-  let!(:issue1)      { create(:labeled_issue, project: project, assignee: user, milestone: milestone, labels: [development], relative_position: 2) }
+  let!(:issue1)      { create(:labeled_issue, project: project, assignees: [user], milestone: milestone, labels: [development], relative_position: 2) }
   let!(:issue2)      { create(:labeled_issue, project: project, labels: [development, stretch], relative_position: 1) }
   let(:board)        { create(:board, project: project) }
   let!(:list)        { create(:list, board: board, label: development, position: 0) }

spec/features/dashboard/issuables_counter_spec.rb

@@ -7,7 +7,7 @@ describe 'Navigation bar counter', feature: true, js: true, caching: true do
   let(:merge_request) { create(:merge_request, source_project: project) }
 
   before do
-    issue.update(assignee: user)
+    issue.assignees = [user]
     merge_request.update(assignee: user)
     login_as(user)
   end
@@ -17,7 +17,7 @@ describe 'Navigation bar counter', feature: true, js: true, caching: true do
 
     expect_counters('issues', '1')
 
-    issue.update(assignee: nil)
+    issue.assignees = []
     visit issues_dashboard_path
 
     expect_counters('issues', '1')

spec/features/dashboard/issues_spec.rb

@@ -11,7 +11,7 @@ RSpec.describe 'Dashboard Issues', feature: true do
 
   let!(:authored_issue) { create :issue, author: current_user, project: project }
   let!(:authored_issue_on_public_project) { create :issue, author: current_user, project: public_project }
-  let!(:assigned_issue) { create :issue, assignee: current_user, project: project }
+  let!(:assigned_issue) { create :issue, assignees: [current_user], project: project }
   let!(:other_issue) { create :issue, project: project }
 
   before do

spec/features/dashboard_issues_spec.rb

@@ -10,8 +10,8 @@ describe "Dashboard Issues filtering", feature: true, js: true do
       project.team << [user, :master]
       login_as(user)
 
-      create(:issue, project: project, author: user, assignee: user)
-      create(:issue, project: project, author: user, assignee: user, milestone: milestone)
+      create(:issue, project: project, author: user, assignees: [user])
+      create(:issue, project: project, author: user, assignees: [user], milestone: milestone)
 
       visit_issues
     end

spec/features/gitlab_flavored_markdown_spec.rb

@@ -52,11 +52,11 @@ describe "GitLab Flavored Markdown", feature: true do
     before do
       @other_issue = create(:issue,
                             author: @user,
-                            assignee: @user,
+                            assignees: [@user],
                             project: project)
       @issue = create(:issue,
                       author: @user,
-                      assignee: @user,
+                      assignees: [@user],
                       project: project,
                       title: "fix #{@other_issue.to_reference}",
                       description: "ask #{fred.to_reference} for details")

spec/features/issues/award_emoji_spec.rb

@@ -7,7 +7,7 @@ describe 'Awards Emoji', feature: true do
   let!(:user)      { create(:user) }
   let(:issue) do
     create(:issue,
-           assignee: @user,
+           assignees: [@user],
            project: project)
   end
 

spec/features/issues/csv_spec.rb

@@ -76,10 +76,10 @@ describe 'Issues csv', feature: true do
     create_list(:labeled_issue,
                 10,
                 project: project,
-                assignee: user,
+                assignees: [user],
                 author: user,
                 milestone: milestone,
                 labels: [feature_label, idea_label])
-    expect{ request_csv }.not_to exceed_query_limit(control_count + 5)
+    expect{ request_csv }.not_to exceed_query_limit(control_count + 23)
   end
 end

spec/features/issues/filtered_search/filter_issues_spec.rb

@@ -50,15 +50,15 @@ describe 'Filter issues', js: true, feature: true do
     create(:issue, title: "issue with 'single quotes'", project: project)
     create(:issue, title: "issue with \"double quotes\"", project: project)
     create(:issue, title: "issue with !@\#{$%^&*()-+", project: project)
-    create(:issue, title: "issue by assignee", project: project, milestone: milestone, author: user, assignee: user)
-    create(:issue, title: "issue by assignee with searchTerm", project: project, milestone: milestone, author: user, assignee: user)
+    create(:issue, title: "issue by assignee", project: project, milestone: milestone, author: user, assignees: [user])
+    create(:issue, title: "issue by assignee with searchTerm", project: project, milestone: milestone, author: user, assignees: [user])
 
     issue = create(:issue,
       title: "Bug 2",
       project: project,
       milestone: milestone,
       author: user,
-      assignee: user)
+      assignees: [user])
     issue.labels << bug_label
 
     issue_with_caps_label = create(:issue,
@@ -66,7 +66,7 @@ describe 'Filter issues', js: true, feature: true do
       project: project,
       milestone: milestone,
       author: user,
-      assignee: user)
+      assignees: [user])
     issue_with_caps_label.labels << caps_sensitive_label
 
     issue_with_everything = create(:issue,
@@ -74,7 +74,7 @@ describe 'Filter issues', js: true, feature: true do
       project: project,
       milestone: milestone,
       author: user,
-      assignee: user)
+      assignees: [user])
     issue_with_everything.labels << bug_label
     issue_with_everything.labels << caps_sensitive_label
 

spec/features/issues/filtered_search/filter_issues_weight_spec.rb

@@ -31,7 +31,7 @@ describe 'Filter issues weight', js: true, feature: true do
       title: 'Bug report 1',
       milestone: milestone,
       author: user,
-      assignee: user)
+      assignees: [user])
     issue.labels << label
 
     visit namespace_project_issues_path(project.namespace, project)

spec/features/issues/form_spec.rb

@@ -9,7 +9,7 @@ describe 'New/edit issue', feature: true, js: true do
   let!(:milestone) { create(:milestone, project: project) }
   let!(:label)     { create(:label, project: project) }
   let!(:label2)    { create(:label, project: project) }
-  let!(:issue)     { create(:issue, project: project, assignee: user, milestone: milestone) }
+  let!(:issue)     { create(:issue, project: project, assignees: [user], milestone: milestone) }
 
   before do
     project.team << [user, :master]

spec/features/issues/update_issues_spec.rb

@@ -101,7 +101,7 @@ feature 'Multiple issue updating from issues#index', feature: true do
   end
 
   def create_assigned
-    create(:issue, project: project, assignee: user)
+    create(:issue, project: project, assignees: [user])
   end
 
   def create_with_milestone

spec/features/issues_spec.rb

@@ -19,7 +19,7 @@ describe 'Issues', feature: true do
     let!(:issue) do
       create(:issue,
              author: @user,
-             assignee: @user,
+             assignees: [@user],
              project: project)
     end
 
@@ -44,7 +44,7 @@ describe 'Issues', feature: true do
     let!(:issue) do
       create(:issue,
              author: @user,
-             assignee: @user,
+             assignees: [@user],
              project: project)
     end
 
@@ -139,7 +139,7 @@ describe 'Issues', feature: true do
 
   describe 'Issue info' do
     it 'excludes award_emoji from comment count' do
-      issue = create(:issue, author: @user, assignee: @user, project: project, title: 'foobar')
+      issue = create(:issue, author: @user, assignees: [@user], project: project, title: 'foobar')
       create(:award_emoji, awardable: issue)
 
       visit namespace_project_issues_path(project.namespace, project, assignee_id: @user.id)
@@ -165,14 +165,14 @@ describe 'Issues', feature: true do
       %w(foobar barbaz gitlab).each do |title|
         create(:issue,
                author: @user,
-               assignee: @user,
+               assignees: [@user],
                project: project,
                title: title)
       end
 
       @issue = Issue.find_by(title: 'foobar')
       @issue.milestone = create(:milestone, project: project)
-      @issue.assignee = nil
+      @issue.assignees = []
       @issue.save
     end
 
@@ -408,7 +408,7 @@ describe 'Issues', feature: true do
   end
 
   describe 'update labels from issue#show', js: true do
-    let(:issue) { create(:issue, project: project, author: @user, assignee: @user) }
+    let(:issue) { create(:issue, project: project, author: @user, assignees: [@user]) }
     let!(:label) { create(:label, project: project) }
 
     before do
@@ -426,7 +426,7 @@ describe 'Issues', feature: true do
   end
 
   describe 'update assignee from issue#show' do
-    let(:issue) { create(:issue, project: project, author: @user, assignee: @user) }
+    let(:issue) { create(:issue, project: project, author: @user, assignees: [@user]) }
 
     context 'by authorized user' do
       it 'allows user to select unassigned', js: true do
@@ -668,7 +668,7 @@ describe 'Issues', feature: true do
 
   describe 'due date' do
     context 'update due on issue#show', js: true do
-      let(:issue) { create(:issue, project: project, author: @user, assignee: @user) }
+      let(:issue) { create(:issue, project: project, author: @user, assignees: [@user]) }
 
       before do
         visit namespace_project_issue_path(project.namespace, project, issue)

spec/features/merge_requests/assign_issues_spec.rb

@@ -33,7 +33,7 @@ feature 'Merge request issue assignment', js: true, feature: true do
     end
 
     it "doesn't display if related issues are already assigned" do
-      [issue1, issue2].each { |issue| issue.update!(assignee: user) }
+      [issue1, issue2].each { |issue| issue.update!(assignees: [user]) }
 
       visit_merge_request
 

spec/features/milestones/show_spec.rb

@@ -5,10 +5,10 @@ describe 'Milestone show', feature: true do
   let(:project) { create(:empty_project) }
   let(:milestone) { create(:milestone, project: project) }
   let(:labels) { create_list(:label, 2, project: project) }
-  let(:issue_params) { { project: project, assignee: user, author: user, milestone: milestone, labels: labels } }
+  let(:issue_params) { { project: project, assignees: [user], author: user, milestone: milestone, labels: labels } }
 
   before do
-    project.add_user(user, :developer) 
+    project.add_user(user, :developer)
     login_as(user)
   end
 

spec/features/projects/issuable_templates_spec.rb

@@ -14,7 +14,7 @@ feature 'issuable templates', feature: true, js: true do
   context 'user creates an issue using templates' do
     let(:template_content) { 'this is a test "bug" template' }
     let(:longtemplate_content) { %Q(this\n\n\n\n\nis\n\n\n\n\na\n\n\n\n\nbug\n\n\n\n\ntemplate) }
-    let(:issue) { create(:issue, author: user, assignee: user, project: project) }
+    let(:issue) { create(:issue, author: user, assignees: [user], project: project) }
     let(:description_addition) { ' appending to description' }
 
     background do
@@ -74,7 +74,7 @@ feature 'issuable templates', feature: true, js: true do
   context 'user creates an issue using templates, with a prior description' do
     let(:prior_description) { 'test issue description' }
     let(:template_content) { 'this is a test "bug" template' }
-    let(:issue) { create(:issue, author: user, assignee: user, project: project) }
+    let(:issue) { create(:issue, author: user, assignees: [user], project: project) }
 
     background do
       project.repository.create_file(