9 files changed, 43 insertions, 33 deletions
diff --git a/app/serializers/issuable_sidebar_extras_entity.rb b/app/serializers/issuable_sidebar_extras_entity.rb
index d60253564e1..fb35b7522c5 100644
--- a/app/serializers/issuable_sidebar_extras_entity.rb
+++ b/app/serializers/issuable_sidebar_extras_entity.rb
@@ -11,4 +11,6 @@ class IssuableSidebarExtrasEntity < Grape::Entity
   expose :subscribed do |issuable|
     issuable.subscribed?(request.current_user, issuable.project)
   end
+
+  expose :assignees, using: API::Entities::UserBasic
 end
diff --git a/app/serializers/issue_board_entity.rb b/app/serializers/issue_board_entity.rb
index f7719447b92..e0041eff6cc 100644
--- a/app/serializers/issue_board_entity.rb
+++ b/app/serializers/issue_board_entity.rb
@@ -2,6 +2,7 @@
 
 class IssueBoardEntity < Grape::Entity
   include RequestAwareEntity
+  include TimeTrackableEntity
 
   expose :id
   expose :iid
diff --git a/app/serializers/issue_sidebar_extras_entity.rb b/app/serializers/issue_sidebar_extras_entity.rb
index 7b6e860140b..dee891a50b7 100644
--- a/app/serializers/issue_sidebar_extras_entity.rb
+++ b/app/serializers/issue_sidebar_extras_entity.rb
@@ -1,5 +1,4 @@
 # frozen_string_literal: true
 
 class IssueSidebarExtrasEntity < IssuableSidebarExtrasEntity
-  expose :assignees, using: API::Entities::UserBasic
 end
diff --git a/app/serializers/merge_request_assignee_entity.rb b/app/serializers/merge_request_assignee_entity.rb
new file mode 100644
index 00000000000..6849c62e759
--- /dev/null
+++ b/app/serializers/merge_request_assignee_entity.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class MergeRequestAssigneeEntity < ::API::Entities::UserBasic
+  expose :can_merge do |assignee, options|
+    options[:merge_request]&.can_be_merged_by?(assignee)
+  end
+end
diff --git a/app/serializers/merge_request_basic_entity.rb b/app/serializers/merge_request_basic_entity.rb
index 178e72f4f0a..973e971b4c0 100644
--- a/app/serializers/merge_request_basic_entity.rb
+++ b/app/serializers/merge_request_basic_entity.rb
@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 class MergeRequestBasicEntity < Grape::Entity
-  expose :assignee_id
   expose :merge_status
   expose :merge_error
   expose :state
@@ -9,7 +8,7 @@ class MergeRequestBasicEntity < Grape::Entity
   expose :rebase_in_progress?, as: :rebase_in_progress
   expose :milestone, using: API::Entities::Milestone
   expose :labels, using: LabelEntity
-  expose :assignee, using: API::Entities::UserBasic
+  expose :assignees, using: API::Entities::UserBasic
   expose :task_status, :task_status_short
   expose :lock_version, :lock_version
 end
diff --git a/app/serializers/merge_request_serializer.rb b/app/serializers/merge_request_serializer.rb
index 4cf84336aa4..6f589351670 100644
--- a/app/serializers/merge_request_serializer.rb
+++ b/app/serializers/merge_request_serializer.rb
@@ -8,9 +8,9 @@ class MergeRequestSerializer < BaseSerializer
     entity =
       case opts[:serializer]
       when 'sidebar'
-        MergeRequestSidebarBasicEntity
+        IssuableSidebarBasicEntity
       when 'sidebar_extras'
-        IssuableSidebarExtrasEntity
+        MergeRequestSidebarExtrasEntity
       when 'basic'
         MergeRequestBasicEntity
       else
diff --git a/app/serializers/merge_request_sidebar_basic_entity.rb b/app/serializers/merge_request_sidebar_basic_entity.rb
deleted file mode 100644
index 0ae7298a7c1..00000000000
--- a/app/serializers/merge_request_sidebar_basic_entity.rb
+++ /dev/null
@@ -1,11 +0,0 @@
-# frozen_string_literal: true
-
-class MergeRequestSidebarBasicEntity < IssuableSidebarBasicEntity
-  expose :assignee, if: lambda { |issuable| issuable.assignee } do
-    expose :assignee, merge: true, using: API::Entities::UserBasic
-
-    expose :can_merge do |issuable|
-      issuable.can_be_merged_by?(issuable.assignee)
-    end
-  end
-end
diff --git a/app/serializers/merge_request_sidebar_extras_entity.rb b/app/serializers/merge_request_sidebar_extras_entity.rb
new file mode 100644
index 00000000000..7276509c363
--- /dev/null
+++ b/app/serializers/merge_request_sidebar_extras_entity.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class MergeRequestSidebarExtrasEntity < IssuableSidebarExtrasEntity
+  expose :assignees do |merge_request|
+    MergeRequestAssigneeEntity.represent(merge_request.assignees, merge_request: merge_request)
+  end
+end
diff --git a/app/serializers/pipeline_serializer.rb b/app/serializers/pipeline_serializer.rb
index dbbeca9431d..95d73c6422d 100644
--- a/app/serializers/pipeline_serializer.rb
+++ b/app/serializers/pipeline_serializer.rb
@@ -7,23 +7,7 @@ class PipelineSerializer < BaseSerializer
   # rubocop: disable CodeReuse/ActiveRecord
   def represent(resource, opts = {})
     if resource.is_a?(ActiveRecord::Relation)
-      resource = resource.preload([
-        :stages,
-        :retryable_builds,
-        :cancelable_statuses,
-        :trigger_requests,
-        :manual_actions,
-        :scheduled_actions,
-        :artifacts,
-        :merge_request,
-        {
-          pending_builds: :project,
-          project: [:route, { namespace: :route }],
-          artifacts: {
-            project: [:route, { namespace: :route }]
-          }
-        }
-      ])
+      resource = resource.preload(preloaded_relations)
     end
 
     if paginated?
@@ -51,4 +35,26 @@ class PipelineSerializer < BaseSerializer
     data = represent(resource, { only: [{ details: [:stages] }], preload: true })
     data.dig(:details, :stages) || []
   end
+
+  private
+
+  def preloaded_relations
+    [
+      :stages,
+      :retryable_builds,
+      :cancelable_statuses,
+      :trigger_requests,
+      :manual_actions,
+      :scheduled_actions,
+      :artifacts,
+      :merge_request,
+      {
+        pending_builds: :project,
+        project: [:route, { namespace: :route }],
+        artifacts: {
+          project: [:route, { namespace: :route }]
+        }
+      }
+    ]
+  end
 end