From: marcandre-ruby-core@...
Date: 2020-10-28T20:48:14+00:00
Subject: [ruby-core:100624] [Ruby master Feature#17288] Optimize __send__ call with a literal method name

Issue #17288 has been updated by marcandre (Marc-Andre Lafortune).


shyouhei (Shyouhei Urabe) wrote in #note-4:
> Private methods shall not be called at the first place. Period. That is breaking encapsulation.

I wish that was the case, but Ruby access is *not expressive enough* for this to be the case.

```ruby
class Foo
  class << self
    private def special # General users should not call or rely on `special`
    end
  end

  def foo # even from inside our own class...
    self.class.special # this won't work without `send`
  end

  class Bar
    # Bar is a helper class, written by us
    def foo 
      Foo.special # we want to call special, we need to use `send`
    end
  end
end
```
Note: using `protected` changes nothing in this example

In so many gems, you have to either mark method as `private` and use `send`, or else use `# @api private` but that's just a comment.

----------------------------------------
Feature #17288: Optimize __send__ call with a literal method name
https://bugs.ruby-lang.org/issues/17288#change-88257

* Author: mrkn (Kenta Murata)
* Status: Open
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
----------------------------------------
I made a patch to optimize a `__send__` call with a literal method name.  This optimization replaces a `__send__` method call with a `send` instruction.  The patch is available in [this pull-request](https://github.com/ruby/ruby/pull/3707).

By this change, the redefined `__send__` method is no longer called when it is called by a literal method name.  I guess it is no problem because the following warning message is displayed for a long time.

    $ ruby -e 'def __send__; end'
    -e:1: warning: redefining `__send__' may cause serious problems

This change makes the optimized case x5~x6 faster.  The benchmark result is below:

```
$ make benchmark COMPARE_RUBY="../../ruby/build-o3/ruby" ITEM=vm_send.yml
(snip)
# Iteration per second (i/s)

|             |compare-ruby|built-ruby|
|:------------|-----------:|---------:|
|vm_send      |     18.536M|  113.778M|
|             |           -|     6.14x|
|vm_send_var  |     18.085M|   16.595M|
|             |       1.09x|         -|
```



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