[neilvcarvalho]

This is the first of a sequence of refactors toward a compiled, non-cloning core. Each step is meant to leave the acceptance suite green and delete machinery that later steps no longer need.

What changed

Resolving a factory's callbacks, constructor and to_create through its parent chain used to build one anonymous subclass of DefinitionHierarchy per factory and rely on Ruby method lookup and super() to perform the inheritance. This replaces that with three methods on Factory that fold over the parent:

def callbacks
  parent.callbacks + definition.callbacks
end

def compiled_to_create
  definition.to_create || parent.compiled_to_create
end

def compiled_constructor
  definition.constructor || parent.compiled_constructor
end

NullFactory ends the recursion by answering with Internal.callbacks, Internal.constructor and Internal.to_create, which is exactly what the root DefinitionHierarchy delegated to before. Callback order is unchanged: global callbacks first, then each ancestor's in parent-to-child order, then the factory's own. definition.callbacks on a compiled definition already includes callbacks aggregated from traits, so no trait handling moves.

Deleted

• lib/factory_bot/definition_hierarchy.rb and its require in lib/factory_bot.rb.
• Factory#hierarchy_class, Factory#hierarchy_instance, Factory#build_hierarchy, the build_hierarchy call in Factory#compile, and the @hierarchy_class / @hierarchy_instance resets in Factory#initialize_copy.
• NullFactory#hierarchy_class and the callbacks, constructor and to_create delegations on NullFactory. The spec for NullFactory is updated to match.

Public behavior is unchanged. No acceptance spec or feature was edited.

Verification

All runs on Ruby 4.0.1.

• bundle exec standardrb: no offenses.

• bundle exec rake all_specs (default Gemfile): 334 unit examples, 445 acceptance examples, 4 Cucumber scenarios, all passing.

• BUNDLE_GEMFILE=gemfiles/main.gemfile bundle exec rake all_specs: same counts, all passing.

• BUNDLE_GEMFILE=gemfiles/7.0.gemfile bundle exec rake all_specs: unit and Cucumber passing. The acceptance suite passed in 12 of 14 runs; the two failures were both this timing assertion:

  rspec ./spec/acceptance/activesupport_instrumentation_spec.rb:186 # using ActiveSupport::Instrumentation to track compile_factory interaction tracks proper time of compiling the factory
       Failure/Error: expect(time_to_execute[:user]).to be > 0
  

  That example asserts a strictly positive duration for the factory_bot.compile_factory notification, which Definition#compile emits with no block, so the measured span contains no factory code at all. On ActiveSupport 7.0 the subscriber uses wall-clock Time.now, and a direct measurement of that span in a warm process reports zero about half the time on both main and this branch (1562 of 3000 samples on main, 1702 of 3000 here). It passes in a fresh process because the first notification is slower (0 zero durations in 60 fresh processes on either checkout). main happened to pass 15 of 15 full acceptance runs under the same gemfile, so the flake rate is low in practice, but it is a property of the spec rather than of this change. I did not loosen the spec.