From: marcandre-ruby-core@...
Date: 2021-01-16T00:55:44+00:00
Subject: [ruby-core:102110] [Ruby master Bug#17543] Ractor isolation broken by `self` in shareable proc

Issue #17543 has been updated by marcandre (Marc-Andre Lafortune).


> Probably the self of the Proc should be made Ractor.make_shareable too.

Would that always be the case? would all the following freeze the `self`?

```ruby
class Foo
  def test(&block)
    Ractor.make_shareable(block)
  end

  def foo
    test(&:int) # freeze self or not?
    test{ 2 + 2 } # freeze self or not?
    test{ puts 'hello' } # freeze self or not?
  end
end
```

The idea behind my proposed fix is to permit all three above without deep-freezing the `self`.


----------------------------------------
Bug #17543: Ractor isolation broken by `self` in shareable proc
https://bugs.ruby-lang.org/issues/17543#change-89966

* Author: marcandre (Marc-Andre Lafortune)
* Status: Open
* Priority: Normal
* Assignee: ko1 (Koichi Sasada)
* ruby -v: 3.0.0p0
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
Discussing with @MaxLap we realized that the `self` in a shareable proc is not properly isolated:

```
class Foo
  attr_accessor :x

  def pr
    Ractor.make_shareable(Proc.new { self })
  end
end

f = Foo.new
f.x = [1, 2, 3]
Ractor.new(f.pr) { |pr| pr.call.x << :oops }
p f.x # => [1, 2, 3, :oops]
```

If the `self` refers to a shareable object then it's fine, but for non-shareable objects it has to be reset to `nil` or to a global shareable object that would have an instructive `inspect`.

```ruby
Ractor::DETACHED_SELF = Object.new
def << Ractor::DETACHED_SELF
  def inspect
    '<#detached self>'
  end
  alias to_s inspect
end
Ractor::DETACHED_SELF.freeze
```




-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request@ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>