From: "mame (Yusuke Endoh) via ruby-core" <ruby-core@...>
Date: 2025-02-13T09:21:01+00:00
Subject: [ruby-core:120973] [Ruby master Feature#21028] Method for finding why an object isn't Ractor shareable

Issue #21028 has been updated by mame (Yusuke Endoh).


Is `ObjectSpace.reachable_objects_from` usable for the use case? It's a bit tedious, but I think it's more flexible not only to get an unshareable object, but also to get the path to the object in question.

```ruby
require "objspace"

def find_path_to_unshareable_object(obj, path = [], visited = {})
  path += [obj]
  return if visited[obj]
  visited[obj] = true

  return if Ractor.shareable?(obj)

  objs = ObjectSpace.reachable_objects_from(obj)
  return path if objs.all? { Ractor.shareable?(it) }

  objs.each do |obj2|
    res = find_path_to_unshareable_object(obj2, path, visited)
    return res if res
  end
  return nil
end

pp *find_path_to_unshareable_object([1, 2, 3, "str".freeze, { :key => -> {} }])
#=> [1, 2, 3, "str", {key: #<Proc:0x00007f0a38e0ff30 t.rb:20 (lambda)>}]
#=> {key: #<Proc:0x00007f0a38e0ff30 t.rb:20 (lambda)>}
#=> #<Proc:0x00007f0a38e0ff30 t.rb:20 (lambda)>
#=> main
```

----------------------------------------
Feature #21028: Method for finding why an object isn't Ractor shareable
https://bugs.ruby-lang.org/issues/21028#change-111874

* Author: tenderlovemaking (Aaron Patterson)
* Status: Open
* Assignee: tenderlovemaking (Aaron Patterson)
----------------------------------------
`Ractor.shareable?` is easy to use, but if it returns false I would like to be able to figure out what object is causing the data structure to _not_ be Ractor shareable.

The context is that I'm trying to make some complex data structures in Rails deeply frozen. If they are deeply frozen they _should_ be Ractor shareable, but `Ractor.shareable?` is returning `false` and it's hard for me to figure out _why_.

I would like a method that would either return all unshareable references, or a method that takes a block and unshareable references are yielded to the block.

A method like `Ractor.unshareable_references?` or maybe `Ractor.shareable?(obj) { |not_shareable_obj| }` would be very helpful for discovering why an object is not shareable.

Thanks!



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