[ruby-core:126214] [Ruby Feature#9779] Add Module#descendants

31 Jul 2026

      Issue #9779 has been updated by shugo (Shugo Maeda).

I've added specs to the pull request: https://github.com/ruby/ruby/pull/17807/changes/ed81db60a57ec586d4c5300282bc...

----------------------------------------
Feature #9779: Add Module#descendants
https://bugs.ruby-lang.org/issues/9779#change-118296

* Author: shugo (Shugo Maeda)
* Status: Open
----------------------------------------
Now classes have links to their subclasses, so how about to add Module#descendents?

```ruby
class X
end

class Y < X
end

class Z < Y
end

p X.descendents    #=> [X, Y, Z]

module A
end

module B
  include A
end

module C
  include A
end

p A.descendents    #=> [A, C, B]
```

One of my own use cases is to implement AspectJ like pointcut which matches all subclasses of the given class.

Considerations:

* Should the return value of Module#descendents include self?
* Should the return value of Module#descendents include singleton classes?

I attach a patch, where the return value includes both self and singleton classes.

---Files--------------------------------
0001-Add-Module-descendents.patch (3.75 KB)

-- 
https://bugs.ruby-lang.org/