Fix SQL error when sorting 2FA-enabled users by name in admin area

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/models/member.rb

@@ -103,7 +103,7 @@ class Member < ActiveRecord::Base
     def filter_by_2fa(value)
       case value
       when 'enabled'
-        left_join_users.merge(User.with_two_factor_indistinct)
+        left_join_users.merge(User.with_two_factor)
       when 'disabled'
         left_join_users.merge(User.without_two_factor)
       else

app/models/user.rb

@@ -289,13 +289,16 @@ class User < ActiveRecord::Base
     end
   end
 
-  def self.with_two_factor_indistinct
-    joins("LEFT OUTER JOIN u2f_registrations AS u2f ON u2f.user_id = users.id")
-      .where("u2f.id IS NOT NULL OR users.otp_required_for_login = ?", true)
-  end
-
   def self.with_two_factor
-    with_two_factor_indistinct.distinct(arel_table[:id])
+    with_u2f_registrations = <<-SQL
+      EXISTS (
+        SELECT *
+        FROM u2f_registrations AS u2f
+        WHERE u2f.user_id = users.id
+      ) OR users.otp_required_for_login = ?
+    SQL
+
+    where(with_u2f_registrations, true)
   end
 
   def self.without_two_factor

spec/models/user_spec.rb

@@ -315,6 +315,14 @@ describe User do
         expect(users_with_two_factor).to eq([user_with_2fa.id])
         expect(users_with_two_factor).not_to include(user_without_2fa.id)
       end
+
+      it 'works with ORDER BY' do
+        user_with_2fa = create(:user, :two_factor_via_otp, :two_factor_via_u2f)
+
+        expect(described_class
+          .with_two_factor
+          .reorder_by_name).to eq([user_with_2fa])
+      end
     end
 
     describe ".without_two_factor" do