From: "Eregon (Benoit Daloze)" <noreply@...>
Date: 2022-09-29T13:52:32+00:00
Subject: [ruby-core:110148] [Ruby master Bug#18435] Calling `protected` on ancestor method changes result of `instance_methods(false)`

Issue #18435 has been updated by Eregon (Benoit Daloze).


@nagachika Could you also backport the commits of https://github.com/ruby/ruby/pull/6467 ?
The semantics and final code in proc.c is much closer to what it was in 3.1 before the backport just above, so it seems best to backport it for compatibility with both previous Ruby releases and upcoming 3.2.
This still fixes the issue with visibility methods, hence it's worth backporting, it's just dealing slightly differently with zsuper methods.

----------------------------------------
Bug #18435: Calling `protected` on ancestor method changes result of `instance_methods(false)`
https://bugs.ruby-lang.org/issues/18435#change-99406

* Author: ufuk (Ufuk Kayserilioglu)
* Status: Closed
* Priority: Normal
* Assignee: Eregon (Benoit Daloze)
* ruby -v: ruby 2.7.5p203 (2021-11-24 revision f69aeb8314) [x86_64-darwin20]
* Backport: 2.6: DONTNEED, 2.7: DONTNEED, 3.0: DONTNEED, 3.1: DONE
----------------------------------------
As documented `instance_methods(false)` works as follows:

```ruby
module A
  def method1()  end
end

class B
  include A

  def method2()  end
end

p B.instance_methods(false) #=> [:method2]
```

However, calling `protected` on the method defined by `A`, unexpectedly changes the result of `instance_methods(false)` on `B`, even though the owner of the method is still `A`:
```ruby
module A
  def method1()  end
end

class B
  include A

  protected :method1

  def method2()  end
end

p B.instance_methods(false) #=> [:method1, :method2]
p B.instance_method(:method1).owner #=> A
```

In contrast, calling `private` or `public` on the same method does not cause any changes on the result of `B.instance_methods(false)`.

This feels like a bug in the implementation of `instance_methods(false)`, but, if it is by design, it should at least be documented on `Module#instance_methods`.

This reproduction script gives the same output all the way from Ruby 2.0 up to Ruby-HEAD:
https://wandbox.org/permlink/LqbXMBTYxURRZmDz



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