Treat empty values for member permissions IDs better

app/models/user/permissions.rb

@@ -6,8 +6,6 @@ module User::Permissions
   extend ActiveSupport::Concern
 
   ATTRIBUTES = %I[role member_permission_ids member_permission_service_ids].freeze
-  # The value that can be used for setting the member permission service ids to empty array
-  EMPTY_VALUE = "[]"
 
   included do
     has_many :member_permissions, dependent: :destroy, autosave: true
@@ -60,7 +58,8 @@ def member_permission_ids=(roles)
 
   def member_permission_service_ids=(service_ids)
     if service_ids.is_a? Array
-      service_ids = (service_ids.compact_blank - [EMPTY_VALUE]).map(&:to_i)
+      # remove all non-integer values
+      service_ids = service_ids.map { Integer(_1, exception: false) }.compact_blank
       member_permission = services_member_permission || member_permissions.build(admin_section: :services)
       member_permission.service_ids = service_ids & existing_service_ids
     elsif service_ids.blank?

test/unit/user/permissions_test.rb

@@ -75,7 +75,7 @@ class User::PermissionsTest < ActiveSupport::TestCase
     assert_equal 1, user.admin_sections.size
 
     # all values have the same effect
-    [[], [""], ["[]"]].each do |service_ids_empty_value|
+    [[], [""], ["[]"], ["xyz"]].each do |service_ids_empty_value|
       user.update(member_permission_service_ids: service_ids_empty_value)
       assert_not user.has_access_to_service?(42)
       assert_equal Set[:partners, :services], user.admin_sections
@@ -93,6 +93,12 @@ class User::PermissionsTest < ActiveSupport::TestCase
       assert_equal Set[:partners, :services], user.admin_sections
       assert_equal [42], user.member_permission_service_ids
     end
+
+    # if 0 is a valid service_id, it can be set as an allowed service
+    user.stubs(:existing_service_ids).returns([0, 42])
+    user.update(member_permission_service_ids: ['0'])
+    assert user.has_access_to_service?(0)
+    assert_equal [0], user.member_permission_service_ids
   end
 
   test 'member_permission_service_ids= filters the services list before saving' do