From: "tenderlovemaking (Aaron Patterson) via ruby-core" <ruby-core@...>
Date: 2025-08-23T23:41:20+00:00
Subject: [ruby-core:123062] [Ruby Bug#21551] Ractor isolation error points to the wrong place

Issue #21551 has been reported by tenderlovemaking (Aaron Patterson).

----------------------------------------
Bug #21551: Ractor isolation error points to the wrong place
https://bugs.ruby-lang.org/issues/21551

* Author: tenderlovemaking (Aaron Patterson)
* Status: Open
* Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN
----------------------------------------
The following code has a bug in it.  The block passed to `Ractor.new` references the outer `channel` variable, so it can't be isolated.  The problem is that I forgot to add `|channel|` to the block:

```ruby
channel = Ractor::Port.new

coordinator = Ractor.new(channel) do
  inbound_work = Ractor::Port.new
  channel << inbound_work
end
```

However, the exception this raises is strange:

```
> ruby thing.rb
thing.rb:3: warning: Ractor is experimental, and the behavior may change in future versions of Ruby! Also there are many implementation issues.
thing.rb:3:in 'Ractor.new': can not isolate a Proc because it accesses outer variables (channel). (ArgumentError)

coordinator = Ractor.new(channel) do
                         ^^^^^^^
	from thing.rb:3:in '<main>'
```

I would expect the `channel` local inside the block to be underlined instead of the parameter passed to `Ractor.new`.



-- 
https://bugs.ruby-lang.org/
______________________________________________
 ruby-core mailing list -- ruby-core@ml.ruby-lang.org
 To unsubscribe send an email to ruby-core-leave@ml.ruby-lang.org
 ruby-core info -- https://ml.ruby-lang.org/mailman3/lists/ruby-core.ml.ruby-lang.org/