1) User state machine and default attributes raises errors by default
     Failure/Error: expect { model }.to raise_error(ZeroDivisionError)
       expected ZeroDivisionError but nothing was raised
     # ./spec/models/user_spec.rb:9989:in `block (3 levels) in <main>'
     # ./spec/spec_helper.rb:595:in `block (2 levels) in <top (required)>'
     # ./spec/spec_helper.rb:487:in `block (3 levels) in <top (required)>'
     # ./lib/gitlab/sidekiq_sharding/validator.rb:42:in `enabled'
     # ./spec/spec_helper.rb:486:in `block (2 levels) in <top (required)>'
     # ./spec/spec_helper.rb:481:in `block (3 levels) in <top (required)>'
     # ./spec/support/sidekiq_middleware.rb:9:in `with_sidekiq_server_middleware'
     # ./spec/spec_helper.rb:471:in `block (2 levels) in <top (required)>'
     # ./spec/spec_helper.rb:467:in `block (3 levels) in <top (required)>'
     # ./lib/gitlab/application_context.rb:109:in `with_raw_context'
     # ./spec/spec_helper.rb:467:in `block (2 levels) in <top (required)>'
     # ./spec/spec_helper.rb:438:in `block (3 levels) in <top (required)>'
     # ./lib/gitlab/ci/config/feature_flags.rb:38:in `ensure_correct_usage'
     # ./spec/spec_helper.rb:437:in `block (2 levels) in <top (required)>'
     # ./spec/support/system_exit_detected.rb:7:in `block (2 levels) in <main>'
     # ./spec/support/fast_quarantine.rb:22:in `block (2 levels) in <main>'
     # ./spec/support/database/prevent_cross_joins.rb:107:in `block (3 levels) in <main>'
     # ./spec/support/database/prevent_cross_joins.rb:61:in `with_cross_joins_prevented'
     # ./spec/support/database/prevent_cross_joins.rb:107:in `block (2 levels) in <main>'
Finished in 1 minute 3.56 seconds (files took 1 minute 13.14 seconds to load)
1 example, 1 failure
Failed examples:
rspec ./spec/models/user_spec.rb:9988 # User state machine and default attributes raises errors by default

$ sudo gitlab-rails c
Both Namespace and its :state machine have defined a different default for "state". Use only one or the other for defining defaults to avoid unexpected behaviors.

 state                                              | smallint                    |           |          | 0                                      | plain    |             |              |

      state_machine :state, initial: :ancestor_inherited do

# Gets the initial attribute value defined by the owner class (outside of
# the machine's definition). By default, this is always nil.
def owner_class_attribute_default
  nil
end

# Checks whether the given state matches the attribute default specified
# by the owner class.
def owner_class_attribute_default_matches?(state)
  state.matches?(owner_class_attribute_default)
end

# Checks for a conflicting attribute default between the owner class and
# the machine. Called from initial_state= but can be deferred by integrations.
def check_conflicting_attribute_default
  initial_state = states.detect(&:initial)
  has_owner_default = !owner_class_attribute_default.nil?
  has_conflicting_default = dynamic_initial_state? || !owner_class_attribute_default_matches?(initial_state)
  return unless has_owner_default && has_conflicting_default

  warn(
    "Both #{owner_class.name} and its #{name.inspect} machine have defined " \
    "a different default for \"#{attribute}\". Use only one or the other for " \
    'defining defaults to avoid unexpected behaviors.'
  )
end

# Schedules or runs the conflicting attribute default check.
# Override in integrations to defer the check (e.g., until after the DB is ready).
def schedule_conflicting_attribute_default_check
  check_conflicting_attribute_default
end

def initial_state=(new_initial_state)
  @initial_state = new_initial_state
  add_states([@initial_state]) unless dynamic_initial_state?

  # Update all states to reflect the new initial state
  states.each { |state| state.initial = (state.name == @initial_state) }

  # Check for a conflicting default on the owner class attribute.
  # May be deferred by integrations (e.g. ActiveRecord) to avoid
  # DB queries during the Rails/Sidekiq initializer phase.
  schedule_conflicting_attribute_default_check
end

def schedule_conflicting_attribute_default_check
  machine = self
  # Defer until AR is fully loaded to avoid touching the DB during
  # the Rails/Sidekiq initializer phase.
  ActiveSupport.on_load(:active_record) do
    machine.check_conflicting_attribute_default
  end
end

def owner_class_attribute_default
  # The connection safety is now handled by the scheduler above.
  # This guard is kept as a defensive fallback.
  return unless owner_class.connected? && owner_class.table_exists?

  owner_class.column_defaults[attribute.to_s]
end

$ objdump -t ./opt/gitlab/embedded/lib/ruby/gems/3.4.0/gems/io-event-1.12.1/lib/IO_Event.so | grep epoll_
0000000000000000       F *UND*	0000000000000000              epoll_create1@GLIBC_2.9
0000000000000000       F *UND*	0000000000000000              epoll_ctl@GLIBC_2.3.2
0000000000000000       F *UND*	0000000000000000              epoll_wait@GLIBC_2.3.2

$ objdump -t ./opt/gitlab/embedded/lib/ruby/gems/3.4.0/gems/io-event-1.12.1/lib/IO_Event.so | grep epoll_
0000000000000000       F *UND*	0000000000000000              epoll_create1@GLIBC_2.9
0000000000000000       F *UND*	0000000000000000              epoll_ctl@GLIBC_2.3.2
0000000000000000       F *UND*	0000000000000000              epoll_wait@GLIBC_2.3.2

$ objdump -t ./opt/gitlab/embedded/lib/ruby/gems/3.4.0/gems/io-event-1.12.1/lib/IO_Event.so | grep epoll_
0000000000000000       F *UND*	0000000000000000              epoll_create1@GLIBC_2.9
0000000000000000       F *UND*	0000000000000000              epoll_ctl@GLIBC_2.3.2
0000000000000000       F *UND*	0000000000000000              epoll_wait@GLIBC_2.3.2
0000000000000000       F *UND*	0000000000000000              epoll_pwait2@GLIBC_2.35