[PATCH] alexandria-1/io.lisp: (read-stream-content-into-string): fix recent regression

[Michał "phoe" Herda]

This doesn't look like a problem on the Alexandria side. Stuffing ub8 
values into any place that requires characters *always* requires 
additional information about character encoding (is it latin1? latin2? 
windows-1250?) and dealing with character encodings is out of scope of 
Alexandria. I think that Flexi Streams/Babel should be explicitly used 
in this context.

On 20.08.2022 18:35, Madhu wrote:
> * alexandria-1/io.lisp: (read-stream-content-into-string): fix recent
> lossage: This addresses problems in commits (13b1575, 6ff6820,
> 9c97e6f, on 2021-10-24), which changed the element-type of the array
> used by READ-SEQUENCE to read from the stream from CHARACTER to the
> STREAM-ELEMENT-TYPE of the stream.
>
> On CCL, ECL etc. this breaks nyxt's source/start.lisp:(listen-socket)
> which basically does
> (iolib:with-open-socket (s :address-family :local :connect :passive :local-filename "/tmp/foo")
>    (alexandria:read-stream-content-into-string (iolib:accept-connection s)))
>
> Iolib returns an octet stream for which the STREAM-ELEMENT-TYPE is not
> CHARACTER. READ-STREAM-CONTENT-INTO-STRING uses WITH-OUTPUT-TO-STRING
> and that calls MAKE-STRING-OUTPUT-STREAM, the argument
> :ELEMENT-TYPE ((UNSIGNED-BYTE 8)) which fails because it must be a
> subtype of character
>
> The present fix is to check if it is not a character stream and force
> set the element-type to 'character if it is not.
> ---
>   alexandria-1/io.lisp | 2 ++
>   1 file changed, 2 insertions(+)
>
> diff --git a/alexandria-1/io.lisp b/alexandria-1/io.lisp
> index d3be536..8c93dd6 100644
> --- a/alexandria-1/io.lisp
> +++ b/alexandria-1/io.lisp
> @@ -65,6 +65,8 @@ (defun read-stream-content-into-string (stream &key (buffer-size 4096))
>     (check-type buffer-size positive-integer)
>     (let ((*print-pretty* nil)
>           (element-type (stream-element-type stream)))
> +    (unless (subtypep element-type 'character)
> +      (setq element-type 'character))
>       (with-output-to-string (datum nil :element-type element-type)
>         (let ((buffer (make-array buffer-size :element-type element-type)))
>           (loop