From: "mame (Yusuke Endoh) via ruby-core" <ruby-core@...>
Date: 2025-03-21T08:54:32+00:00
Subject: [ruby-core:121427] [Ruby Bug#21193] Inherited callback returns `nil` for `Object.const_source_location`

Issue #21193 has been updated by mame (Yusuke Endoh).


It was understandable that you wanted `class C < D` to behave the same as `C = Class.new(D)` for the sake of consistency.
However, the change proposed in this ticket intentionally differentiates these two behaviors, which seems to spoil the original motivation.
If we cannot make it consistent eventually, it is unclear to me why this order change was necessary.

If @matz prefers to change the order even in this halfway state, I don't mind, but we need to confirm.

----------------------------------------
Bug #21193: Inherited callback returns `nil` for `Object.const_source_location`
https://bugs.ruby-lang.org/issues/21193#change-112409

* Author: eileencodes (Eileen Uchitelle)
* Status: Assigned
* Assignee: matz (Yukihiro Matsumoto)
* Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN
----------------------------------------
Since https://github.com/ruby/ruby/pull/12927 the inherited callback no longer can access the `Object.const_source_location`. A simplified reproduction is the following:

```ruby
class A
  def self.inherited(other)
    super
    p Object.const_source_location(other.name)
  end 
end

class B < A 
end
```

Prior to this change `Object.const_source_location(other.name)` would return `["test.rb", 8]` and now returns `nil`.

Shopify's application uses the `inherited` callback to load configuration classes and since it's unable to find these classes they aren't loaded when they are called. It's not clear if this was intended or if there's a workaround. In chatting with folks at GitHub, they have a similar issue (although that case sounds less straightforward). A more accurate example of what we have (I did strip this down a bunch too):

```ruby

def self.inherited(config)
  return super unless config.superclass == Config

  if (class_name = config.name) &&
    (config_location = Object.const_source_location(class_name)) &&
    (parent_dirname = File.dirname(config_location[0]))
    config_dirname = File.join(parent_dirname, "config")
      config.autoload(:Something, File.join(config_dirname, "something.rb"))
  end

  super
end
```

Original issue: https://bugs.ruby-lang.org/issues/21143

cc/ @byroot @fxn 



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