Make private root_dirs internal and rename to roots

lib/zeitwerk/loader.rb

@@ -116,8 +116,8 @@ def setup
       mutex.synchronize do
         break if @setup
 
-        actual_root_dirs.each do |root_dir, namespace|
-          set_autoloads_in_dir(root_dir, namespace)
+        actual_roots.each do |root_dir, root_namespace|
+          set_autoloads_in_dir(root_dir, root_namespace)
         end
 
         on_setup_callbacks.each(&:call)
@@ -447,7 +447,7 @@ def raise_if_conflicting_directory(dir)
           next if loader == self
           next if loader.__ignores?(dir)
 
-          loader.root_dirs.each do |root_dir, _namespace|
+          loader.__roots.each do |root_dir, _root_namespace|
             next if ignores?(root_dir)
 
             root_dir_slash = root_dir + "/"

lib/zeitwerk/loader/config.rb

@@ -23,9 +23,9 @@ module Zeitwerk::Loader::Config
   # This is a private collection maintained by the loader. The public
   # interface for it is `push_dir` and `dirs`.
   #
-  # @private
   # @sig Hash[String, Module]
-  attr_reader :root_dirs
+  attr_reader :roots
+  internal :roots
 
   # Absolute paths of files, directories, or glob patterns to be totally
   # ignored.
@@ -86,7 +86,7 @@ def initialize
     @logger                 = self.class.default_logger
     @tag                    = SecureRandom.hex(3)
     @initialized_at         = Time.now
-    @root_dirs              = {}
+    @roots                  = {}
     @ignored_glob_patterns  = Set.new
     @ignored_paths          = Set.new
     @collapse_glob_patterns = Set.new
@@ -115,7 +115,7 @@ def push_dir(path, namespace: Object)
     abspath = File.expand_path(path)
     if dir?(abspath)
       raise_if_conflicting_directory(abspath)
-      root_dirs[abspath] = namespace
+      roots[abspath] = namespace
     else
       raise Zeitwerk::Error, "the root directory #{abspath} does not exist"
     end
@@ -148,9 +148,9 @@ def tag=(tag)
   # @sig () -> Array[String] | Hash[String, Module]
   def dirs(namespaces: false)
     if namespaces
-      root_dirs.clone
+      roots.clone
     else
-      root_dirs.keys
+      roots.keys
     end.freeze
   end
 
@@ -284,22 +284,22 @@ def log!
 
     walk_up(abspath) do |abspath|
       return true  if ignored_paths.member?(abspath)
-      return false if root_dirs.key?(abspath)
+      return false if roots.key?(abspath)
     end
 
     false
   end
 
   # @sig () -> Array[String]
-  private def actual_root_dirs
-    root_dirs.reject do |root_dir, _namespace|
+  private def actual_roots
+    roots.reject do |root_dir, _root_namespace|
       !dir?(root_dir) || ignored_paths.member?(root_dir)
     end
   end
 
   # @sig (String) -> bool
   private def root_dir?(dir)
-    root_dirs.key?(dir)
+    roots.key?(dir)
   end
 
   # @sig (String) -> bool
@@ -309,7 +309,7 @@ def log!
 
     walk_up(abspath) do |abspath|
       return true  if eager_load_exclusions.member?(abspath)
-      return false if root_dirs.key?(abspath)
+      return false if roots.key?(abspath)
     end
 
     false

lib/zeitwerk/loader/eager_load.rb

@@ -12,8 +12,8 @@ def eager_load(force: false)
 
       log("eager load start") if logger
 
-      actual_root_dirs.each do |root_dir, namespace|
-        actual_eager_load_dir(root_dir, namespace, force: force)
+      actual_roots.each do |root_dir, root_namespace|
+        actual_eager_load_dir(root_dir, root_namespace, force: force)
       end
 
       autoloaded_dirs.each do |autoloaded_dir|
@@ -40,7 +40,7 @@ def eager_load_dir(path)
       return if ignored_paths.member?(dir)
       return if eager_load_exclusions.member?(dir)
 
-      break if root_namespace = root_dirs[dir]
+      break if root_namespace = roots[dir]
 
       unless collapse?(dir)
         basename = File.basename(dir)
@@ -76,7 +76,7 @@ def eager_load_namespace(mod)
     mod_name = real_mod_name(mod)
     return unless mod_name
 
-    actual_root_dirs.each do |root_dir, root_namespace|
+    actual_roots.each do |root_dir, root_namespace|
       if mod.equal?(Object)
         # A shortcircuiting test depends on the invocation of this method.
         # Please keep them in sync if refactored.
@@ -122,7 +122,7 @@ def load_file(path)
     walk_up(File.dirname(abspath)) do |dir|
       raise Zeitwerk::Error.new("#{abspath} is ignored") if ignored_paths.member?(dir)
 
-      break if root_namespace = root_dirs[dir]
+      break if root_namespace = roots[dir]
 
       unless collapse?(dir)
         basename = File.basename(dir)

lib/zeitwerk/loader/helpers.rb

@@ -31,7 +31,7 @@ def ls(dir)
       next if ignored_paths.member?(abspath)
 
       if dir?(abspath)
-        next if root_dirs.key?(abspath)
+        next if roots.key?(abspath)
         next if !has_at_least_one_ruby_file?(abspath)
       else
         next unless ruby?(abspath)

test/lib/zeitwerk/test_push_dir.rb

@@ -7,16 +7,16 @@ class TesPushDir < LoaderTest
   module Namespace; end
 
   def check_dirs
-    root_dirs = loader.root_dirs # this is private interface
+    roots = loader.__roots
 
     dirs = loader.dirs
-    assert_equal root_dirs.keys, dirs
+    assert_equal roots.keys, dirs
     assert dirs.frozen?
 
     dirs = loader.dirs(namespaces: true)
-    assert_equal root_dirs, dirs
+    assert_equal roots, dirs
     assert dirs.frozen?
-    assert !dirs.equal?(root_dirs)
+    assert !dirs.equal?(roots)
   end
 
   test "accepts dirs as strings and associates them to the Object namespace" do