bug#39811: Missing dynwind exit application

bug#39811: Missing dynwind exit application

[Stefan Israelsson Tampe]

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Executing this code on guile-3.0.0:

(dynamic-wind
 (lambda () (pk 'enter))
 (lambda () (catch #t
              (lambda () (throw 1))
              (lambda x (pk 'catch x) (apply throw x))))
 (lambda () (pk 'leave)))

Leads to the output:

scheme@(guile-user)> (load "bug.scm")
;;; (enter)
;;; (catch (a))

ice-9/boot-9.scm:1669:16: In procedure raise-exception:
Throw to key `a' with args `()'.

What, it does not execute the leave part of the dynamic wind.

This works however,

(catch #t
  (lambda ()
    (dynamic-wind
      (lambda () (pk 'enter))
      (lambda () (catch #t
                   (lambda () (throw 'a))
                   (lambda x (pk 'catch x) (apply throw x))))
      (lambda () (pk 'leave))))
  (lambda x #f))

So is this how it should be?

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bug#39811: Missing dynwind exit application

[Andy Wingo]

Stefan Israelsson Tampe <stefan.itampe@gmail.com> writes:

> Executing this code on guile-3.0.0:
>
> (dynamic-wind
>  (lambda () (pk 'enter))
>  (lambda () (catch #t
>               (lambda () (throw 1))
>               (lambda x (pk 'catch x) (apply throw x))))
>  (lambda () (pk 'leave)))
>
> Leads to the output:
>
> scheme@(guile-user)> (load "bug.scm") 
> ;;; (enter) 
> ;;; (catch (a)) 
>
> ice-9/boot-9.scm:1669:16: In procedure raise-exception: 
> Throw to key `a' with args `()'. 
>
> What, it does not execute the leave part of the dynamic wind.

That is because the REPL leaves you in the context of where the uncaught
error was thrown.  If you ,quit the REPL to go back to the outer REPL,
it will print "leave" as expected.  Please reopen if I have
misunderstood :)

Cheers,

Andy