Fix namespaces_helper reporting multiple groups

app/helpers/namespaces_helper.rb

@@ -14,8 +14,11 @@ module NamespacesHelper
       extra_group = Group.find(extra_group) if Namespace.find(extra_group).kind == 'group'
     end
 
-    if extra_group && extra_group.is_a?(Group) && (!Group.exists?(name: extra_group.name) || Ability.allowed?(current_user, :read_group, extra_group))
-      groups |= [extra_group]
+    if extra_group && extra_group.is_a?(Group)
+      # Avoid duplicate groups if one already exists by that name
+      existing_group = Group.find_by(name: extra_group.name)
+      extra_group = existing_group if existing_group
+      groups |= [extra_group] if Ability.allowed?(current_user, :read_group, extra_group)
     end
 
     options = []

spec/helpers/namespaces_helper_spec.rb

@@ -31,6 +31,15 @@ describe NamespacesHelper do
       expect(options).to include(user.name)
     end
 
+    it 'avoids duplicate groups when extra_group is used' do
+      allow(helper).to receive(:current_user).and_return(admin)
+
+      options = helper.namespaces_options(user_group.id, display_path: true, extra_group: build(:group, name: admin_group.name))
+
+      expect(options.scan("data-name=\"#{admin_group.name}\"").count).to eq(1)
+      expect(options).to include(admin_group.name)
+    end
+
     it 'returns only groups if groups_only option is true' do
       allow(helper).to receive(:current_user).and_return(user)