From: "Eregon (Benoit Daloze)" <noreply@...>
Date: 2022-06-09T10:33:31+00:00
Subject: [ruby-core:108834] [Ruby master Bug#18729] Method#owner and UnboundMethod#owner are incorrect after using Module#public/protected/private

Issue #18729 has been updated by Eregon (Benoit Daloze).

Status changed from Rejected to Open

mame (Yusuke Endoh) wrote in #note-17:
> @matz changed his mind: https://bugs.ruby-lang.org/issues/18435#note-11
> 
> So the original problem in this ticket ("Method#owner and UnboundMethod#owner are incorrect") is considered a spec.

I cannot agree that to possibly be spec, I would like @matz to reconsider and this time we just remove "ZSUPER methods" entirely to make it simple and intuitive (instead we shallow-copy like for alias_method).
The current CRuby behavior is very confusing and should be removed, it's bringing needless complexity and confusion.
See https://bugs.ruby-lang.org/issues/18435#note-12 for details.

----------------------------------------
Bug #18729: Method#owner and UnboundMethod#owner are incorrect after using Module#public/protected/private
https://bugs.ruby-lang.org/issues/18729#change-97910

* Author: Eregon (Benoit Daloze)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.1.1p18 (2022-02-18 revision 53f5fc4236) [x86_64-linux]
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN
----------------------------------------
The #owner should be "the class or module that defines the method".
Or in other words, the owner is the module which has the method table containing that method.

This generally holds, and it seems very likely this assumption is relied upon (e.g., when decorating a method, undefining it, etc).
But the returned value on CRuby is incorrect for this case:
```ruby
class A
  protected def foo
    :A
  end
end

class B < A
  p [instance_method(:foo), instance_method(:foo).owner, instance_methods(false), A.instance_methods(false)]
  public :foo
  p [instance_method(:foo), instance_method(:foo).owner, instance_methods(false), A.instance_methods(false)]
end
```

It gives:
```
[#<UnboundMethod: B(A)#foo() owner.rb:2>, A, [], [:foo]]
[#<UnboundMethod: B(A)#foo() owner.rb:2>, A, [:foo], [:foo]]
```

So `UnboundMethod#owner` says `A`, but clearly there is a :foo method entry in B created by `public :foo`, and that is shown through `B.instance_methods(false)`.

The expected output is:

```
[#<UnboundMethod: B(A)#foo() owner.rb:2>, A, [], [:foo]]
[#<UnboundMethod: B#foo() owner.rb:2>, B, [:foo], [:foo]]
```



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