Module: Zeitwerk::Loader::Callbacks

Included in:
Zeitwerk::Loader
Defined in:
lib/zeitwerk/loader/callbacks.rb

Instance Method Summary collapse

Instance Method Details

#on_dir_autoloaded(dir) ⇒ void

This method returns an undefined value.

Invoked from our decorated Kernel#require when a managed directory is autoloaded.

Parameters:

  • dir (String) 


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# File 'lib/zeitwerk/loader/callbacks.rb', line 25

def on_dir_autoloaded(dir)
  # Module#autoload does not serialize concurrent requires, and we handle
  # directories ourselves, so the callback needs to account for concurrency.
  #
  # Multi-threading would introduce a race condition here in which thread t1
  # autovivifies the module, and while autoloads for its children are being
  # set, thread t2 autoloads the same namespace.
  #
  # Without the mutex and subsequent delete call, t2 would reset the module.
  # That not only would reassign the constant (undesirable per se) but, worse,
  # the module object created by t2 wouldn't have any of the autoloads for its
  # children, since t1 would have correctly deleted its lazy_subdirs entry.
  mutex2.synchronize do
    if cref = autoloads.delete(dir)
      autovivified_module = cref[0].const_set(cref[1], Module.new)
      log("module #{autovivified_module.name} autovivified from directory #{dir}") if logger

      to_unload[autovivified_module.name] = [dir, cref] if reloading_enabled?

      # We don't unregister `dir` in the registry because concurrent threads
      # wouldn't find a loader associated to it in Kernel#require and would
      # try to require the directory. Instead, we are going to keep track of
      # these to be able to unregister later if eager loading.
      autoloaded_dirs << dir

      on_namespace_loaded(autovivified_module)
    end
  end
end

#on_file_autoloaded(file) ⇒ void

This method returns an undefined value.

Invoked from our decorated Kernel#require when a managed file is autoloaded.

Parameters:

  • file (String) 


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# File 'lib/zeitwerk/loader/callbacks.rb', line 7

def on_file_autoloaded(file)
  cref = autoloads.delete(file)
  to_unload[cpath(*cref)] = [file, cref] if reloading_enabled?
  Zeitwerk::Registry.unregister_autoload(file)

  if logger && cdef?(*cref)
    log("constant #{cpath(*cref)} loaded from file #{file}")
  elsif !cdef?(*cref)
    raise NameError, "expected file #{file} to define constant #{cpath(*cref)}, but didn't"
  end
end

#on_namespace_loaded(namespace) ⇒ void

This method returns an undefined value.

Invoked when a class or module is created or reopened, either from the tracer or from module autovivification. If the namespace has matching subdirectories, we descend into them now.

Parameters:

  • namespace (Module) 


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# File 'lib/zeitwerk/loader/callbacks.rb', line 62

def on_namespace_loaded(namespace)
  if subdirs = lazy_subdirs.delete(namespace.name)
    subdirs.each do |subdir|
      set_autoloads_in_dir(subdir, namespace)
    end
  end
end