GNU bug report logs - #23404
Infinite recursion in GOOPS in Guile 2.2

Previous Next

Full log

View this message in rfc822 format

From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Andy Wingo <wingo <at> pobox.com>
Cc: tracker <at> debbugs.gnu.org
Subject: bug#23404: closed (Infinite recursion in GOOPS in Guile 2.2)
Date: Tue, 28 Feb 2017 15:13:02 +0000

[Message part 1 (text/plain, inline)]

Your message dated Tue, 28 Feb 2017 16:12:46 +0100
with message-id <87lgsql575.fsf <at> pobox.com>
and subject line Re: bug#23404: Infinite recursion in GOOPS in Guile 2.2
has caused the debbugs.gnu.org bug report #23404,
regarding Infinite recursion in GOOPS in Guile 2.2
to be marked as done.

(If you believe you have received this mail in error, please contact
help-debbugs <at> gnu.org.)


-- 
23404: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=23404
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

[Message part 2 (message/rfc822, inline)]

From: Christopher Allan Webber <cwebber <at> dustycloud.org>
To: bug-guile <at> gnu.org
Subject: Infinite recursion in GOOPS in Guile 2.2
Date: Fri, 29 Apr 2016 19:27:56 -0500

Heya all,

So I've been building something with GOOPS, and I decided to try it out
with Guile 2.2.  Unfortunately, I hit a pretty nasty bug.  You can try
it yourself... the code is pretty short:

  (use-modules (oop goops)
               (srfi srfi-9))
  (define-class <some-class> ())
  (define-method (time-to-break (some-class <some-class>) not-a-class)
    (display "We're never going home are we?\n"))

  ;; And now, call it
  (time-to-break (make <some-class>) 1)

This will loop forever and *never* complete.  Why?

Turns out this is why, from goops.scm:

  (define (single-arity-cache-dispatch cache nargs cache-miss)
    (match cache
      (() cache-miss)
      (((typev . cmethod) . cache)
       (cond
        ((eqv? nargs (vector-length typev))
         (let ((cache-miss (single-arity-cache-dispatch cache nargs cache-miss)))

I'm not sure what was supposed to happen (presumably the cache was
supposed to be narrowed down somehow), but what happens here is that
single-arity-cache-dispatch keeps calling single-arity-cache-dispatch
forever.

scheme@(guile-user) [1]> ,bt
In oop/goops.scm:
   1437:41939 (cache-miss #<<hive> e8a1e0> #<<message> id: "5c787e65bbeb34b27ffd16eead286fc6:1" to: ("8394701db8…>)
   1486:41938 (memoize-effective-method! _ _ _)
  1466:131937 (recompute-generic-function-dispatch-procedure! #<<generic> hive-process-message (1)>)
  1452:161936 (compute-generic-function-dispatch-procedure _)
  1378:251935 (single-arity-cache-dispatch _ 2 _)
  1378:251934 (single-arity-cache-dispatch _ 2 _)
  1378:251933 (single-arity-cache-dispatch _ 2 _)
  1378:251932 (single-arity-cache-dispatch _ 2 _)
  1378:251931 (single-arity-cache-dispatch _ 2 _)
  1378:251930 (single-arity-cache-dispatch _ 2 _)
  1378:251929 (single-arity-cache-dispatch _ 2 _)
  1378:251928 (single-arity-cache-dispatch _ 2 _)
  1378:251927 (single-arity-cache-dispatch _ 2 _)
  1378:251926 (single-arity-cache-dispatch _ 2 _)
  1378:251925 (single-arity-cache-dispatch _ 2 _)
  1378:251924 (single-arity-cache-dispatch _ 2 _)
  ... etc ...

(g?)Oops!

 - Chris

[Message part 3 (message/rfc822, inline)]

From: Andy Wingo <wingo <at> pobox.com>
To: Christopher Allan Webber <cwebber <at> dustycloud.org>
Cc: 23404-done <at> debbugs.gnu.org
Subject: Re: bug#23404: Infinite recursion in GOOPS in Guile 2.2
Date: Tue, 28 Feb 2017 16:12:46 +0100

On Sat 30 Apr 2016 04:27, Christopher Allan Webber <cwebber <at> dustycloud.org> writes:

> It looks like my example was incomplete.  It turns out loading and
> passing in an srfi-9 record is critical to instantiating the bug.
>
> Why?  I'm not sure...
>
>   (use-modules (oop goops)
>                (srfi srfi-9))
>   (define-class <some-class> ())
>   (define-record-type <some-record>
>     (make-some-record foo)
>     some-record?
>     (foo some-record-foo))
>   
>   (define-method (time-to-break (some-class <some-class>) not-a-class)
>     (display "We're never going home are we?\n"))
>   
>   ;; Now it'll break
>   (time-to-break (make <some-class>) (make-some-record 1))

This appears to be fixed, somehow (?).  Please reopen if you can still
produce the bug.

Andy

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.