[flexi-streams-devel] *substitution-char* does not suppress external-format-encoding-error

[Edi Weitz]

Sorry for the delay.  I think this is more or less "on purpose."
(It's been a while since I wrote that stuff...)

The recover-from-encoding-error helper function is used when during
decoding we encounter something which "looks like" a character (so to
say) but isn't one - in which case we can e.g. replace it with the
substitution character.

I think the error you mention happens earlier - when the length is checked.

Of course, one could argue that one could just as well use the same
restart here.  Maybe you can just submit a patch (including
documentation if needed and ideally with new tests) and convince Hans
to make a new release?

Thanks,
Edi.


On Sat, Jan 21, 2012 at 1:06 PM, Dmitriy Ivanov <divanov11 at gmail.com> wrote:
> Hello folks,
>
> I have bumped into the following error while playing with Hunchentoot.
> (It is originated from url-decoding GET parameters with
>  *hunchentoot-default-external-format*.)
>
> (let ((flex:*substitution-char* #\?))
>  (flex:octets-to-string #(#xC1 #xC2 #xC3 #xC4) :external-format :utf-8))
> => "??"
>
> (let ((flex:*substitution-char* #\?))
>  (flex:octets-to-string #(#xC0 #xC1 #xC2 #xC3 #xC4) :external-format
> :utf-8))
> -> signals: This sequence can't be decoded using UTF-8 as it is too short.
> 1
> octet missing at then end.
>
> The reason is rather "simple": the decoder invokes the following chain of calls:
>  compute-number-of-chars -> check-end -> signal-encoding-error
>
> This contrasts to the most of decoder code, which directly calls
>   recover-from-encoding-error
> instead of
>  signal-encoding-error.
> --
> Sincerely,
> Dmitriy Ivanov
> lisp.ystok.ru
>
>
>
>
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