FormHelper#issue_assignees_dropdown_options never has multiple assignees

app/helpers/form_helper.rb

@@ -16,8 +16,8 @@ module FormHelper
     end
   end
 
-  def issue_dropdown_options(issuable, has_multiple_assignees = true)
-    options = {
+  def issue_assignees_dropdown_options
+    {
       toggle_class: 'js-user-search js-assignee-search js-multiselect js-save-user-data',
       title: 'Select assignee',
       filter: true,
@@ -27,8 +27,8 @@ module FormHelper
         first_user: current_user&.username,
         null_user: true,
         current_user: true,
-        project_id: issuable.project.try(:id),
-        field_name: "#{issuable.class.model_name.param_key}[assignee_ids][]",
+        project_id: @project.id,
+        field_name: 'issue[assignee_ids][]',
         default_label: 'Unassigned',
         'max-select': 1,
         'dropdown-header': 'Assignee',
@@ -38,13 +38,5 @@ module FormHelper
         current_user_info: current_user.to_json(only: [:id, :name])
       }
     }
-
-    if has_multiple_assignees
-      options[:title] = 'Select assignee(s)'
-      options[:data][:'dropdown-header'] = 'Assignee(s)'
-      options[:data].delete(:'max-select')
-    end
-
-    options
   end
 end

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

@@ -7,5 +7,5 @@
     - if issuable.assignees.length === 0
       = hidden_field_tag "#{issuable.to_ability_name}[assignee_ids][]", 0, id: nil, data: { meta: '' }
 
-    = dropdown_tag(users_dropdown_label(issuable.assignees), options: issue_dropdown_options(issuable,false))
+    = dropdown_tag(users_dropdown_label(issuable.assignees), options: issue_assignees_dropdown_options)
   = link_to 'Assign to me', '#', class: "assign-to-me-link #{'hide' if issuable.assignees.include?(current_user)}"

spec/features/issues/form_spec.rb

@@ -31,8 +31,8 @@ describe 'New/edit issue', :feature, :js do
         # the original method, resulting in infinite recurison when called.
         # This is likely a bug with helper modules included into dynamically generated view classes.
         # To work around this, we have to hold on to and call to the original implementation manually.
-        original_issue_dropdown_options = FormHelper.instance_method(:issue_dropdown_options)
-        allow_any_instance_of(FormHelper).to receive(:issue_dropdown_options).and_wrap_original do |original, *args|
+        original_issue_dropdown_options = FormHelper.instance_method(:issue_assignees_dropdown_options)
+        allow_any_instance_of(FormHelper).to receive(:issue_assignees_dropdown_options).and_wrap_original do |original, *args|
           options = original_issue_dropdown_options.bind(original.receiver).call(*args)
           options[:data][:per_page] = 2