[debbugs-tracker] bug#17466: closed (unexpected bytevector contents with get-bytevector-n)

[GNU bug Tracking System]

Your message dated Wed, 28 May 2014 19:32:22 +0200
with message-id <address@hidden>
and subject line Re: bug#17466: unexpected bytevector contents with 
get-bytevector-n
has caused the debbugs.gnu.org bug report #17466,
regarding unexpected bytevector contents with get-bytevector-n
to be marked as done.

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-- 
17466: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=17466
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> --- Begin Message ---
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> Subject: 
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> unexpected bytevector contents with get-bytevector-n
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> Date: 
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> Sun, 11 May 2014 13:00:23 +0200
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> User-agent: 
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> Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0
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> concerning the following code example
> --
> (import (rnrs io ports) (ice-9 pretty-print))
> (define (problem-part port) (pretty-print (get-bytevector-n port 4096)))
>
> (let loop ((count 100))
>   (if (> count 0)
>     (begin (call-with-input-string "22222222222222222222" problem-part)
> (loop (- count 1)))))
> __
>
> when i run it i get output with portions like this
> --
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> #vu8(0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0)
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> #vu8(0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0)
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> #vu8(50 50 50 50 50 50 50 50 16 224 240 0 0 0 0 0 50 50 50 50)
> #vu8(50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50 50)
> --
>
> and i would expect the bytevector to always be the same.
>
> this first occurred to me in a more complicated scenario where:
>   - the input port is a file-port
>   - pretty-print was used at first and then display instead, but the
> problem persisted with a much lower frequency
>
> system info
>   guile 2.0.11
>   linux 3.14.2-1-ARCH x86_64
>
>
>
> --- End Message ---
> --- Begin Message ---
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>
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> Subject: 
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> Re: bug#17466: unexpected bytevector contents with get-bytevector-n
>
>
>
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> Date: 
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> Wed, 28 May 2014 19:32:22 +0200
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>
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> User-agent: 
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> Gnus/5.130009 (Ma Gnus v0.9) Emacs/24.3 (gnu/linux)
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>
> This is fixed by commit 1baa215, which will be in Guile 2.0.12.
>
> It turns out that when shrinking a bytevector, as happens before
> ‘get-bytevector-n’ returns, the pointer to the bytevector’s contents
> would not be left pointing to the old bytevector.  When that old
> bytevector was eventually reclaimed, anything could happen.
>
> Thanks!
>
> Ludo’.
>
>
> --- End Message ---