Merge pull request #30624 from bogdanvlviv/deprecate_Module_reachable

Deprecate `Module#reachable?` method

activesupport/CHANGELOG.md

+*   Deprecate `Module#reachable?` method.
+
+    *bogdanvlviv*
+
 *   Add `config/credentials.yml.enc` to store production app secrets.
 
     Allows saving any authentication credentials for third party services

activesupport/lib/active_support/core_ext/class/subclasses.rb

 # frozen_string_literal: true
 
-require_relative "../module/anonymous"
-require_relative "../module/reachable"
-
 class Class
   begin
     # Test if this Ruby supports each_object against singleton_class

activesupport/lib/active_support/core_ext/module/reachable.rb

@@ -7,4 +7,5 @@ class Module
   def reachable? #:nodoc:
     !anonymous? && name.safe_constantize.equal?(self)
   end
+  deprecate :reachable?
 end

activesupport/test/core_ext/module/reachable_test.rb

@@ -5,13 +5,17 @@
 
 class AnonymousTest < ActiveSupport::TestCase
   test "an anonymous class or module is not reachable" do
-    assert !Module.new.reachable?
-    assert !Class.new.reachable?
+    assert_deprecated do
+      assert !Module.new.reachable?
+      assert !Class.new.reachable?
+    end
   end
 
   test "ordinary named classes or modules are reachable" do
-    assert Kernel.reachable?
-    assert Object.reachable?
+    assert_deprecated do
+      assert Kernel.reachable?
+      assert Object.reachable?
+    end
   end
 
   test "a named class or module whose constant has gone is not reachable" do
@@ -21,8 +25,10 @@ class AnonymousTest < ActiveSupport::TestCase
     self.class.send(:remove_const, :C)
     self.class.send(:remove_const, :M)
 
-    assert !c.reachable?
-    assert !m.reachable?
+    assert_deprecated do
+      assert !c.reachable?
+      assert !m.reachable?
+    end
   end
 
   test "a named class or module whose constants store different objects are not reachable" do
@@ -35,9 +41,11 @@ class AnonymousTest < ActiveSupport::TestCase
     eval "class C; end"
     eval "module M; end"
 
-    assert C.reachable?
-    assert M.reachable?
-    assert !c.reachable?
-    assert !m.reachable?
+    assert_deprecated do
+      assert C.reachable?
+      assert M.reachable?
+      assert !c.reachable?
+      assert !m.reachable?
+    end
   end
 end

guides/source/active_support_core_extensions.md

@@ -674,44 +674,6 @@ M.parents       # => [X::Y, X, Object]
 
 NOTE: Defined in `active_support/core_ext/module/introspection.rb`.
 
-### Reachable
-
-A named module is reachable if it is stored in its corresponding constant. It means you can reach the module object via the constant.
-
-That is what ordinarily happens, if a module is called "M", the `M` constant exists and holds it:
-
-```ruby
-module M
-end
-
-M.reachable? # => true
-```
-
-But since constants and modules are indeed kind of decoupled, module objects can become unreachable:
-
-```ruby
-module M
-end
-
-orphan = Object.send(:remove_const, :M)
-
-# The module object is orphan now but it still has a name.
-orphan.name # => "M"
-
-# You cannot reach it via the constant M because it does not even exist.
-orphan.reachable? # => false
-
-# Let's define a module called "M" again.
-module M
-end
-
-# The constant M exists now again, and it stores a module
-# object called "M", but it is a new instance.
-orphan.reachable? # => false
-```
-
-NOTE: Defined in `active_support/core_ext/module/reachable.rb`.
-
 ### Anonymous
 
 A module may or may not have a name:
@@ -745,7 +707,6 @@ end
 
 m = Object.send(:remove_const, :M)
 
-m.reachable? # => false
 m.anonymous? # => false
 ```