GNU bug report logs - #48566
call-with-blocked-asyncs does not like escape continuations

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Package: guile;

Reported by: Maxime Devos <maximedevos <at> telenet.be>

Date: Fri, 21 May 2021 14:29:01 UTC

Severity: normal

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Report forwarded to bug-guile <at> gnu.org:
bug#48566; Package guile. (Fri, 21 May 2021 14:29:01 GMT) Full text and rfc822 format available.
Acknowledgement sent to Maxime Devos <maximedevos <at> telenet.be>:
New bug report received and forwarded. Copy sent to bug-guile <at> gnu.org.

Your message had a Version: pseudo-header with an invalid package version:

3.0.5 (as found on Guix System, on a x86-64 system)

please either use found or fixed to the control server with a correct version, or reply to this report indicating the correct version so the maintainer (or someone else) can correct it for you.

(Fri, 21 May 2021 14:29:01 GMT) Full text and rfc822 format available.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Maxime Devos <maximedevos <at> telenet.be>
To: bug-guile <at> gnu.org
Subject: call-with-blocked-asyncs does not like escape continuations
Date: Fri, 21 May 2021 16:28:27 +0200

[Message part 1 (text/plain, inline)]
Version: 3.0.5 (as found on Guix System, on a x86-64 system)

Here is a minimal reproducer.

(use-modules (ice-9 control))
(define (test)
  (define (safe-point)
    (call-with-unblocked-asyncs (lambda () 'hi)))
  (let/ec
    ec
    (call-with-blocked-asyncs
      (lambda () (system-async-mark ec) (safe-point))))
  (call-with-blocked-asyncs safe-point))
(test)

Output:

ice-9/boot-9.scm:1669:16: In procedure raise-exception:
In procedure call-with-unblocked-asyncs: asyncs already unblocked

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [1]> ,bt
           2 (call-with-blocked-asyncs #<procedure safe-point ()>)
           1 (call-with-unblocked-asyncs #<procedure 7f83245ad2a0 at /home/sylvii…>)
In ice-9/boot-9.scm:
  1669:16  0 (raise-exception _ #:continuable? _)

This bug was found while trying to test whether the definition of with-mutex
is correct in the present of asynchronicities (system-async-mark). (with-mutex
does not use call-with-blocked-asyncs & call-with-unblocked-asyncs, while I
think it should --- what if the Scheme code was interrupted in the 'in-guard'
or 'out-guard' of a dynamic-wind?).

Greetings,
Maxime.

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This bug report was last modified 3 years and 190 days ago.

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