class Zeitwerk::Loader
Constants
- MUTEX
Attributes
@sig call | debug | nil
We keep track of autoloaded directories to remove them from the registry at the end of eager loading.
Files are removed as they are autoloaded, but directories need to wait due to concurrency (see why in Zeitwerk::Loader::Callbacks#on_dir_autoloaded
).
@private @sig Array
Maps absolute paths for which an autoload has been set —and not executed— to their corresponding parent class or module and constant name.
"/Users/fxn/blog/app/models/user.rb" => [Object, :User], "/Users/fxn/blog/app/models/hotel/pricing.rb" => [Hotel, :Pricing] ...
@private @sig Hash[String, [Module, Symbol]]
Maps constant paths of namespaces to arrays of corresponding directories.
For example, given this mapping:
"Admin" => [ "/Users/fxn/blog/app/controllers/admin", "/Users/fxn/blog/app/models/admin", ... ]
when `Admin` gets defined we know that it plays the role of a namespace and that its children are spread over those directories. We'll visit them to set up the corresponding autoloads.
@private @sig Hash[String, Array]
@private @sig Mutex
@private @sig Mutex
Stores metadata needed for unloading. Its entries look like this:
"Admin::Role" => [".../admin/role.rb", [Admin, :Role]]
The cpath as key helps implementing unloadable_cpath? The file name is stored in order to be able to delete it from $LOADED_FEATURES, and the pair [Module, Symbol] is used to remove_const the constant from the class or module object.
If reloading is enabled, this hash is filled as constants are autoloaded or eager loaded. Otherwise, the collection remains empty.
@private @sig Hash[String, [String, [Module, Symbol]]]
Public Class Methods
Returns an array with the absolute paths of the root directories of all registered loaders. This is a read-only collection.
@sig () -> Array
# File lib/zeitwerk/loader.rb, line 325 def all_dirs Registry.loaders.flat_map(&:dirs).freeze end
Broadcasts `eager_load` to all loaders.
@sig () -> void
# File lib/zeitwerk/loader.rb, line 317 def eager_load_all Registry.loaders.each(&:eager_load) end
This is a shortcut for
require "zeitwerk" loader = Zeitwerk::Loader.new loader.tag = File.basename(__FILE__, ".rb") loader.inflector = Zeitwerk::GemInflector.new(__FILE__) loader.push_dir(__dir__)
except that this method returns the same object in subsequent calls from the same file, in the unlikely case the gem wants to be able to reload.
This method returns a subclass of Zeitwerk::Loader
, but the exact type is private, client code can only rely on the interface.
@sig (bool) -> Zeitwerk::GemLoader
# File lib/zeitwerk/loader.rb, line 309 def for_gem(warn_on_extra_files: true) called_from = caller_locations(1, 1).first.path Registry.loader_for_gem(called_from, warn_on_extra_files: warn_on_extra_files) end
Zeitwerk::Loader::Config::new
# File lib/zeitwerk/loader.rb, line 83 def initialize super @autoloads = {} @autoloaded_dirs = [] @to_unload = {} @lazy_subdirs = Hash.new { |h, cpath| h[cpath] = [] } @mutex = Mutex.new @mutex2 = Mutex.new @setup = false @eager_loaded = false Registry.register_loader(self) end
Public Instance Methods
Eager loads all files in the root directories, recursively. Files do not need to be in `$LOAD_PATH`, absolute file names are used. Ignored files are not eager loaded. You can opt-out specifically in specific files and directories with `do_not_eager_load`, and that can be overridden passing `force: true`.
@sig (true | false) -> void
# File lib/zeitwerk/loader.rb, line 218 def eager_load(force: false) mutex.synchronize do break if @eager_loaded log("eager load start") if logger honour_exclusions = !force queue = [] actual_root_dirs.each do |root_dir, namespace| queue << [namespace, root_dir] unless honour_exclusions && excluded_from_eager_load?(root_dir) end while to_eager_load = queue.shift namespace, dir = to_eager_load ls(dir) do |basename, abspath| next if honour_exclusions && excluded_from_eager_load?(abspath) if ruby?(abspath) if cref = autoloads[abspath] cget(*cref) end elsif !root_dirs.key?(abspath) if collapse?(abspath) queue << [namespace, abspath] else cname = inflector.camelize(basename, abspath) queue << [cget(namespace, cname), abspath] end end end end autoloaded_dirs.each do |autoloaded_dir| Registry.unregister_autoload(autoloaded_dir) end autoloaded_dirs.clear @eager_loaded = true log("eager load end") if logger end end
Unloads all loaded code, and calls setup again so that the loader is able to pick any changes in the file system.
This method is not thread-safe, please see how this can be achieved by client code in the README of the project.
@raise [Zeitwerk::Error] @sig () -> void
# File lib/zeitwerk/loader.rb, line 202 def reload raise ReloadingDisabledError unless reloading_enabled? unload recompute_ignored_paths recompute_collapse_dirs setup end
Sets autoloads in the root namespace.
@sig () -> void
# File lib/zeitwerk/loader.rb, line 101 def setup mutex.synchronize do break if @setup actual_root_dirs.each do |root_dir, namespace| set_autoloads_in_dir(root_dir, namespace) end on_setup_callbacks.each(&:call) @setup = true end end
Removes loaded constants and configured autoloads.
The objects the constants stored are no longer reachable through them. In addition, since said objects are normally not referenced from anywhere else, they are eligible for garbage collection, which would effectively unload them.
This method is public but undocumented. Main interface is `reload`, which means `unload` + `setup`. This one is avaiable to be used together with `unregister`, which is undocumented too.
@sig () -> void
# File lib/zeitwerk/loader.rb, line 127 def unload mutex.synchronize do # We are going to keep track of the files that were required by our # autoloads to later remove them from $LOADED_FEATURES, thus making them # loadable by Kernel#require again. # # Directories are not stored in $LOADED_FEATURES, keeping track of files # is enough. unloaded_files = Set.new autoloads.each do |abspath, (parent, cname)| if parent.autoload?(cname) unload_autoload(parent, cname) else # Could happen if loaded with require_relative. That is unsupported, # and the constant path would escape unloadable_cpath? This is just # defensive code to clean things up as much as we are able to. unload_cref(parent, cname) unloaded_files.add(abspath) if ruby?(abspath) end end to_unload.each do |cpath, (abspath, (parent, cname))| unless on_unload_callbacks.empty? begin value = cget(parent, cname) rescue ::NameError # Perhaps the user deleted the constant by hand, or perhaps an # autoload failed to define the expected constant but the user # rescued the exception. else run_on_unload_callbacks(cpath, value, abspath) end end unload_cref(parent, cname) unloaded_files.add(abspath) if ruby?(abspath) end unless unloaded_files.empty? # Bootsnap decorates Kernel#require to speed it up using a cache and # this optimization does not check if $LOADED_FEATURES has the file. # # To make it aware of changes, the gem defines singleton methods in # $LOADED_FEATURES: # # https://github.com/Shopify/bootsnap/blob/master/lib/bootsnap/load_path_cache/core_ext/loaded_features.rb # # Rails applications may depend on bootsnap, so for unloading to work # in that setting it is preferable that we restrict our API choice to # one of those methods. $LOADED_FEATURES.reject! { |file| unloaded_files.member?(file) } end autoloads.clear autoloaded_dirs.clear to_unload.clear lazy_subdirs.clear Registry.on_unload(self) ExplicitNamespace.unregister_loader(self) @setup = false @eager_loaded = false end end
Says if the given constant path would be unloaded on reload. This predicate returns `false` if reloading is disabled.
@sig (String) -> bool
# File lib/zeitwerk/loader.rb, line 267 def unloadable_cpath?(cpath) to_unload.key?(cpath) end
Returns an array with the constant paths that would be unloaded on reload. This predicate returns an empty array if reloading is disabled.
@sig () -> Array
# File lib/zeitwerk/loader.rb, line 275 def unloadable_cpaths to_unload.keys.freeze end
This is a dangerous method.
@experimental @sig () -> void
# File lib/zeitwerk/loader.rb, line 283 def unregister Registry.unregister_loader(self) ExplicitNamespace.unregister_loader(self) end