[ruby-core:117458] [Ruby master Bug#20414] `Fiber#raise` should recurse to `resumed_fiber` rather than failing.

[ruby-core:117458] [Ruby master Bug#20414] `Fiber#raise` should recurse to `resumed_fiber` rather than failing.

[ioquatix (Samuel Williams) via ruby-core]

Issue #20414 has been reported by ioquatix (Samuel Williams).

----------------------------------------
Bug #20414: `Fiber#raise` should recurse to `resumed_fiber` rather than failing.
https://bugs.ruby-lang.org/issues/20414

* Author: ioquatix (Samuel Williams)
* Status: Open
* Assignee: ioquatix (Samuel Williams)
* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
The following program will fail with `FiberError`, and is difficult to properly clean up:

```ruby
root_fiber = Fiber.current

f1 = Fiber.new do
	root_fiber.transfer
end

f2 = Fiber.new do
	f1.resume
end

f2.transfer

f2.raise("error") # => `raise': attempt to transfer to a resuming fiber (FiberError)
```

This program deliberately set's up a scenario where `f2` is resuming `f1`. Trying to raise an exception on `f2` is impossible, because the only way control flow can return to it, is when `f1` yields or exits.

We can avoid this problem, by raising the exception on f1, and we can do this automatically using the following logic:

```c
static VALUE
fiber_raise(rb_fiber_t *fiber, VALUE exception)
{
    // Add this recursive step:
    if (fiber->resuming_fiber) {
        return fiber_raise(fiber->resuming_fiber, exception);
    }

    // Existing code ...
    else if (FIBER_SUSPENDED_P(fiber) && !fiber->yielding) {
        return fiber_transfer_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
    }
    else {
        return fiber_resume_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
    }
}
```

This makes `Fiber#raise` much more robust and useful for the purpose of stopping fibers, without knowing exactly what they are doing.



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[ruby-core:117459] [Ruby master Bug#20414] `Fiber#raise` should recurse to `resumed_fiber` rather than failing.

[ioquatix (Samuel Williams) via ruby-core]

Issue #20414 has been updated by ioquatix (Samuel Williams).


Proposed change: https://github.com/ruby/ruby/pull/10482

----------------------------------------
Bug #20414: `Fiber#raise` should recurse to `resumed_fiber` rather than failing.
https://bugs.ruby-lang.org/issues/20414#change-107843

* Author: ioquatix (Samuel Williams)
* Status: Open
* Assignee: ioquatix (Samuel Williams)
* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
The following program will fail with `FiberError`, and is difficult to properly clean up:

```ruby
root_fiber = Fiber.current

f1 = Fiber.new do
	root_fiber.transfer
end

f2 = Fiber.new do
	f1.resume
end

f2.transfer

f2.raise("error") # => `raise': attempt to transfer to a resuming fiber (FiberError)
```

This program deliberately set's up a scenario where `f2` is resuming `f1`. Trying to raise an exception on `f2` is impossible, because the only way control flow can return to it, is when `f1` yields or exits.

We can avoid this problem, by raising the exception on f1, and we can do this automatically using the following logic:

```c
static VALUE
fiber_raise(rb_fiber_t *fiber, VALUE exception)
{
    // Add this recursive step:
    if (fiber->resuming_fiber) {
        return fiber_raise(fiber->resuming_fiber, exception);
    }

    // Existing code ...
    else if (FIBER_SUSPENDED_P(fiber) && !fiber->yielding) {
        return fiber_transfer_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
    }
    else {
        return fiber_resume_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
    }
}
```

This makes `Fiber#raise` much more robust and useful for the purpose of stopping fibers, without knowing exactly what they are doing.



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[ruby-core:117461] [Ruby master Bug#20414] `Fiber#raise` should recurse to `resumed_fiber` rather than failing.

[ioquatix (Samuel Williams) via ruby-core]

Issue #20414 has been updated by ioquatix (Samuel Williams).


With the proposed change, the following program:

```ruby
root_fiber = Fiber.current

f1 = Fiber.new do
  puts "f1 enter"
  root_fiber.transfer
  puts "f1 exit"
ensure
  puts "f1 ensure"
end

f2 = Fiber.new do
  puts "f2 enter"
  f1.resume
  puts "f2 exit"
ensure
  puts "f2 ensure"
end

f2.transfer

begin
  puts "raise"
  f2.raise(Interrupt)
rescue Interrupt => e
  puts "rescue Interrupt"
end
```

... generates the following output:

```
f2 enter
f1 enter
raise
f1 ensure
f2 ensure
rescue Interrupt
```

----------------------------------------
Bug #20414: `Fiber#raise` should recurse to `resumed_fiber` rather than failing.
https://bugs.ruby-lang.org/issues/20414#change-107848

* Author: ioquatix (Samuel Williams)
* Status: Open
* Assignee: ioquatix (Samuel Williams)
* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
The following program will fail with `FiberError`, and is difficult to properly clean up:

```ruby
root_fiber = Fiber.current

f1 = Fiber.new do
  root_fiber.transfer
end

f2 = Fiber.new do
  f1.resume
end

f2.transfer

f2.raise("error") # => `raise': attempt to transfer to a resuming fiber (FiberError)
```

This program deliberately set's up a scenario where `f2` is resuming `f1`. Trying to raise an exception on `f2` is impossible, because the only way control flow can return to it, is when `f1` yields or exits.

We can avoid this problem, by raising the exception on f1, and we can do this automatically using the following logic:

```c
static VALUE
fiber_raise(rb_fiber_t *fiber, VALUE exception)
{
    // Add this recursive step:
    if (fiber->resuming_fiber) {
        return fiber_raise(fiber->resuming_fiber, exception);
    }

    // Existing code ...
    else if (FIBER_SUSPENDED_P(fiber) && !fiber->yielding) {
        return fiber_transfer_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
    }
    else {
        return fiber_resume_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
    }
}
```

This makes `Fiber#raise` much more robust and useful for the purpose of stopping fibers, without knowing exactly what they are doing.



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[ruby-core:117548] [Ruby master Bug#20414] `Fiber#raise` should recurse to `resumed_fiber` rather than failing.

[matz (Yukihiro Matsumoto) via ruby-core]

Issue #20414 has been updated by matz (Yukihiro Matsumoto).


I see no problem in the proposal. I agree.

Matz.


----------------------------------------
Bug #20414: `Fiber#raise` should recurse to `resumed_fiber` rather than failing.
https://bugs.ruby-lang.org/issues/20414#change-107942

* Author: ioquatix (Samuel Williams)
* Status: Open
* Assignee: ioquatix (Samuel Williams)
* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
The following program will fail with `FiberError`, and is difficult to properly clean up:

```ruby
root_fiber = Fiber.current

f1 = Fiber.new do
  root_fiber.transfer
end

f2 = Fiber.new do
  f1.resume
end

f2.transfer

f2.raise("error") # => `raise': attempt to transfer to a resuming fiber (FiberError)
```

This program deliberately set's up a scenario where `f2` is resuming `f1`. Trying to raise an exception on `f2` is impossible, because the only way control flow can return to it, is when `f1` yields or exits.

We can avoid this problem, by raising the exception on f1, and we can do this automatically using the following logic:

```c
static VALUE
fiber_raise(rb_fiber_t *fiber, VALUE exception)
{
    // Add this recursive step:
    if (fiber->resuming_fiber) {
        return fiber_raise(fiber->resuming_fiber, exception);
    }

    // Existing code ...
    else if (FIBER_SUSPENDED_P(fiber) && !fiber->yielding) {
        return fiber_transfer_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
    }
    else {
        return fiber_resume_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
    }
}
```

This makes `Fiber#raise` much more robust and useful for the purpose of stopping fibers, without knowing exactly what they are doing.



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[ruby-core:117555] [Ruby master Bug#20414] `Fiber#raise` should recurse to `resumed_fiber` rather than failing.

[ioquatix (Samuel Williams) via ruby-core]

Issue #20414 has been updated by ioquatix (Samuel Williams).


Thanks @matz.

To clarify, there are two issues are we addressing.

(1) Improve consistency of `Thread.current.raise` and `Fiber.current.raise`.
(2) Follow `resuming_fiber` when raising exceptions.

They overlap, so are addressed by the same PR.

----------------------------------------
Bug #20414: `Fiber#raise` should recurse to `resumed_fiber` rather than failing.
https://bugs.ruby-lang.org/issues/20414#change-107951

* Author: ioquatix (Samuel Williams)
* Status: Open
* Assignee: ioquatix (Samuel Williams)
* Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN
----------------------------------------
The following program will fail with `FiberError`, and is difficult to properly clean up:

```ruby
root_fiber = Fiber.current

f1 = Fiber.new do
  root_fiber.transfer
end

f2 = Fiber.new do
  f1.resume
end

f2.transfer

f2.raise("error") # => `raise': attempt to transfer to a resuming fiber (FiberError)
```

This program deliberately set's up a scenario where `f2` is resuming `f1`. Trying to raise an exception on `f2` is impossible, because the only way control flow can return to it, is when `f1` yields or exits.

We can avoid this problem, by raising the exception on f1, and we can do this automatically using the following logic:

```c
static VALUE
fiber_raise(rb_fiber_t *fiber, VALUE exception)
{
    // Add this recursive step:
    if (fiber->resuming_fiber) {
        return fiber_raise(fiber->resuming_fiber, exception);
    }

    // Existing code ...
    else if (FIBER_SUSPENDED_P(fiber) && !fiber->yielding) {
        return fiber_transfer_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
    }
    else {
        return fiber_resume_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
    }
}
```

This makes `Fiber#raise` much more robust and useful for the purpose of stopping fibers, without knowing exactly what they are doing.



-- 
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[ruby-core:117563] [Ruby master Bug#20414] `Fiber#raise` should recurse to `resumed_fiber` rather than failing.

[ioquatix (Samuel Williams) via ruby-core]

Issue #20414 has been updated by ioquatix (Samuel Williams).

Status changed from Open to Closed
Backport changed from 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN to 3.1: REQUIRED, 3.2: REQUIRED, 3.3: REQUIRED

Merged in <https://github.com/ruby/ruby/commit/6ade36c06b7cef948099b8f5f483763498705d12>.

----------------------------------------
Bug #20414: `Fiber#raise` should recurse to `resumed_fiber` rather than failing.
https://bugs.ruby-lang.org/issues/20414#change-107962

* Author: ioquatix (Samuel Williams)
* Status: Closed
* Assignee: ioquatix (Samuel Williams)
* Backport: 3.1: REQUIRED, 3.2: REQUIRED, 3.3: REQUIRED
----------------------------------------
The following program will fail with `FiberError`, and is difficult to properly clean up:

```ruby
root_fiber = Fiber.current

f1 = Fiber.new do
  root_fiber.transfer
end

f2 = Fiber.new do
  f1.resume
end

f2.transfer

f2.raise("error") # => `raise': attempt to transfer to a resuming fiber (FiberError)
```

This program deliberately set's up a scenario where `f2` is resuming `f1`. Trying to raise an exception on `f2` is impossible, because the only way control flow can return to it, is when `f1` yields or exits.

We can avoid this problem, by raising the exception on f1, and we can do this automatically using the following logic:

```c
static VALUE
fiber_raise(rb_fiber_t *fiber, VALUE exception)
{
    // Add this recursive step:
    if (fiber->resuming_fiber) {
        return fiber_raise(fiber->resuming_fiber, exception);
    }

    // Existing code ...
    else if (FIBER_SUSPENDED_P(fiber) && !fiber->yielding) {
        return fiber_transfer_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
    }
    else {
        return fiber_resume_kw(fiber, -1, &exception, RB_NO_KEYWORDS);
    }
}
```

This makes `Fiber#raise` much more robust and useful for the purpose of stopping fibers, without knowing exactly what they are doing.



-- 
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