epoll instance is dead

[wingo]

epoll instance is dead

[emixa-d]

Proposed fix: change

    ('dead (error "epoll instance is dead"))))

to

    ;; This can happen if a fiber was waiting on a condition and run-fibers completes before
    ;; the fiber completes and afterwards the condition is signalled.  In that case, we don't
    ;; have to resurrect the fiber or something, we can just do nothing.
    ;; (Bug report: https://github.com/wingo/fibers/issues/61)
    ('dead #t)))

and add the test to the test suite?

(Edit: clarification: I did not test this.)

[emixa-d]

Minimal test case:

(use-modules (fibers) (fibers conditions) (fibers scheduler))

(define c (make-condition))
(run-fibers
 (lambda ()
   (spawn-fiber (lambda () (wait c)))
   (yield-current-task)) ; let the other fiber wait forever
 #:hz 0 #:parallelism 1) ; it fails both with and without, preemption is another complication, so keep things simple for now by not preempting

(signal-condition! c)

[emixa-d]

Description:

When a fiber is waiting on a condition and run-fibers completes before the fiber completes and afterwards the condition is signalled, ‘epoll instance is dead’ results.

[wingo]

Sounds like a good fix to me!

[aconchillo]

Sounds good to me too. @emixa-d can you provide a PR for this? i'll merge right away. thanks!

[emixa-d]

I've made a PR at: #62