[ruby-core:108957] [Ruby master Bug#18729] Method#owner and UnboundMethod#owner are incorrect after using Module#public/protected/private

["matz (Yukihiro Matsumoto)" <noreply@ruby-lang.org>]

Issue #18729 has been updated by matz (Yukihiro Matsumoto).


And if I understand correctly, copying could cause the following code to print "B:B:hello", which is confusing.

```ruby
class A
  private def foo; puts "hello"; end
end
class B<A
  private def foo; print "B:"; super; end
end
class C<B
  public :foo
end
C.new.foo
```

Matz.


----------------------------------------
Bug #18729: Method#owner and UnboundMethod#owner are incorrect after using Module#public/protected/private
https://bugs.ruby-lang.org/issues/18729#change-98053

* Author: Eregon (Benoit Daloze)
* Status: Rejected
* 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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