Allow to use Concurrent::Map#compute_if_absent in a Ractor#1109
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- ### Problem
It is currently not possible to use the `compute_if_absent` method
in a Ractor because there is a NULL object used solely as a sentinel
that isn't shareable.
```ruby
Ractor.new do
map = Concurrent::Map.new
map.compute_if_absent(3) do |map, key|
end
end
# Ractor::IsolationError:
# can not access non-shareable objects in constant Concurrent::NULL by non-main ractor.
```
### Solution
I'd like to simply freeze the object being hold in the `NULL`
constant.
Edouard-chin
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bensheldon
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Jul 9, 2026
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Looks correct to me 👍
Would a release sooner rather than later be helpful for Ractor work?
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|
Thanks for the offer ! This would be super helpful to get a release sooner than later. I'm not seeing any other Ractor fixes for concurrent ruby (we have a backlog of ractor safety issues in a few gems but this was the only in this gem for our current project scope). |
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Allow to use Concurrent::Map#compute_if_absent in a Ractor
Problem
It is currently not possible to use the
compute_if_absentmethod in a Ractor because there is a NULL object used solely as a sentinel that isn't shareable.Solution
I'd like to simply freeze the object being hold in the
NULLconstant.