Update param name to use epic_id

Use epic_id to reflect the param value that will
then be coverted to be the new epic param to later
be used by the UpdateService.

app/assets/javascripts/issuable_bulk_update_actions.js

@@ -87,7 +87,7 @@ export default {
         issuable_ids: this.form.find('input[name="update[issuable_ids]"]').val(),
         subscription_event: this.form.find('input[name="update[subscription_event]"]').val(),
         health_status: this.form.find('input[name="update[health_status]"]').val(),
-        epic: this.form.find('input[name="update[epic_id]"]').val(),
+        epic_id: this.form.find('input[name="update[epic_id]"]').val(),
         add_label_ids: [],
         remove_label_ids: [],
       },

ee/app/controllers/concerns/ee/issuable_actions.rb

@@ -8,7 +8,7 @@ module EE
     EE_PERMITTED_KEYS = %w[
       weight
       health_status
-      epic
+      epic_id
     ].freeze
 
     private

ee/app/services/ee/issuable/bulk_update_service.rb

@@ -26,6 +26,9 @@ module EE
         super
 
         set_health_status
+        set_epic_param
+
+        params
       end
 
       def set_health_status
@@ -34,39 +37,33 @@ module EE
         params[:health_status] = nil if params[:health_status] == IssuableFinder::Params::NONE.to_s
       end
 
-      override :filter_update_params
-      def filter_update_params(type)
-        super
-        set_epic_param
-
-        params
-      end
-
       def set_epic_param
-        return unless params[:epic].present?
+        return unless params[:epic_id].present?
 
-        epic_param = params.delete(:epic)
-        params[:epic] = nil if remove_epic?(epic_param)
-        return if params[:epic].present?
+        epic_id = params.delete(:epic_id)
+        epic = find_epic(epic_id)
 
-        epic = find_epic(epic_param)
-        params[:epic] = epic if epic.present?
+        # Set as nil if removing an epic or set as the Epic object
+        # if epic_id is present and the Epic was found.
+        params[:epic] = epic if epic.nil? || epic.present?
       end
 
       # rubocop: disable CodeReuse/ActiveRecord
-      def find_epic(id)
+      def find_epic(epic_id)
+        return if remove_epic?(epic_id)
+
         group = parent.is_a?(Group) ? parent : parent.group
         return unless group.present?
 
         EpicsFinder.new(current_user, group_id: group.id,
-                        include_ancestor_groups: true).find(id)
+                        include_ancestor_groups: true).find(epic_id)
       rescue ActiveRecord::RecordNotFound
-        nil
+        false
       end
       # rubocop: enable CodeReuse/ActiveRecord
 
-      def remove_epic?(epic_param)
-        epic_param == IssuableFinder::Params::NONE.to_s
+      def remove_epic?(epic_id)
+        epic_id == IssuableFinder::Params::NONE.to_s
       end
     end
   end

ee/app/views/shared/issuable/_group_bulk_update_sidebar.html.haml

 - group = local_assigns.fetch(:group)
 - type = local_assigns.fetch(:type)
 - bulk_issue_health_status_flag = type == :issues && Feature.enabled?(:bulk_update_health_status, group) && group&.feature_available?(:issuable_health_status)
-- epic_bulk_edit_flag = group&.feature_available?(:epics) && type == :issues
+- epic_bulk_edit_flag = type == :issues && group&.feature_available?(:epics)
 
 %aside.issues-bulk-update.js-right-sidebar.right-sidebar{ 'aria-live' => 'polite', data: { 'signed-in': current_user.present? } }
   .issuable-sidebar.hidden

ee/spec/controllers/groups/issues_controller_spec.rb

@@ -19,7 +19,7 @@ RSpec.describe Groups::IssuesController do
         update: {
           milestone_id: milestone.id,
           issuable_ids: "#{issue1.id}, #{issue2.id}",
-          epic: epic.id
+          epic_id: epic.id
           },
           group_id: group
         }

ee/spec/features/issues/bulk_assignment_epic_spec.rb

@@ -2,7 +2,7 @@
 
 require 'spec_helper'
 
-describe 'Issues > Epic bulk assignment' do
+RSpec.describe 'Issues > Epic bulk assignment', :js do
   let_it_be(:user) { create(:user) }
   let_it_be(:group) { create(:group, :public) }
   let_it_be(:project) { create(:project, :public, group: group) }

ee/spec/services/ee/issuable/bulk_update_service_spec.rb

@@ -98,7 +98,7 @@ RSpec.describe Issuable::BulkUpdateService do
 
       context 'when user can not admin epic' do
         let(:epic3) { create(:epic, group: create(:group)) }
-        let(:params) { { issuable_ids: issuables.map(&:id), epic: epic3.id } }
+        let(:params) { { issuable_ids: issuables.map(&:id), epic_id: epic3.id } }
 
         it_behaves_like 'does not update issuables attribute', :epic
       end