Issue #20102 has been reported by ioquatix (Samuel Williams).
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Bug #20102: Introduce `Fiber#resuming?`
https://bugs.ruby-lang.org/issues/20102
* Author: ioquatix (Samuel Williams)
* Status: Open
* Priority: Normal
* Assignee: ioquatix (Samuel Williams)
* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
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There are some tricky edge cases when using `Fibre#raise` and `Fiber#kill`, e.g.
```ruby
fiber = nil
killer = Fiber.new do
fiber.raise("Stop")
end
fiber = Fiber.new do
killer.resume
end
fiber.resume
# 4:in `raise': attempt to raise a resuming fiber (FiberError)
# 4:in `block in <main>'
```
Async has to deal with this edge case explicitly by rescuing the exception:
https://github.com/socketry/async/blob/ffd019d9c1d547926a28fe8f36bf7bfe91d8…
I'd like to avoid doing that and instead just ask "Can I kill/raise on this fiber
right now?" which is determined by whether the fiber itself can be resumed or
transferred to.
To address this, I'd like to introduce `Fiber#resuming?`:
```c
/*
* call-seq: fiber.resumed? -> true or false
*
* Whether the fiber is currently resumed.
*/
VALUE
rb_fiber_resuming_p(VALUE fiber_value)
{
struct rb_fiber_struct *fiber = fiber_ptr(fiber_value);
if (FIBER_TERMINATED_P(fiber)) return RUBY_Qfalse;
return RBOOL(fiber->resuming_fiber);
}
```
See the PR:
https://github.com/ruby/ruby/pull/9382
--
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