Re: master d1c9310: DOn't use string-as-unibyte in Gnus

[Katsumi Yamaoka]

Hi Lars,

On Tue, 31 Jan 2017 16:58:08 +0000, Lars Ingebrigtsen wrote:
> branch: master
> commit d1c931009004aef847105b7bac6b6ffafd985b82
> Author: Lars Ingebrigtsen <address@hidden>
> Commit: Lars Ingebrigtsen <address@hidden>

>     DOn't use string-as-unibyte in Gnus
[...]
>     * lisp/gnus/mml.el (mml-generate-mime-1): Ditto.
[...]
> --- a/lisp/gnus/mml.el
> +++ b/lisp/gnus/mml.el
> @@ -696,9 +696,10 @@ be \"related\" or \"alternate\"."
>             (set-buffer-multibyte nil)
>             (cond
>              ((cdr (assq 'buffer cont))
> -             (insert (string-as-unibyte
> +             (insert (encode-coding-string
>                        (with-current-buffer (cdr (assq 'buffer cont))
> -                        (buffer-string)))))
> +                        (buffer-string))
> +                      'utf-8)))
>              ((and filename
>                    (not (equal (cdr (assq 'nofile cont)) "yes")))
>               (let ((coding-system-for-read mm-binary-coding-system))

This change breaks a jpeg image (at least).  Recipe:

・Visit an image file using `universal-coding-system-argument'
  with `binary' and `find-file', i.e.:
  C-x RET c binary RET C-x C-f FILENAME RET C-c C-c
・Open a message draft.
・Insert this mml tag:

<#part type="image/jpeg" disposition=inline buffer="IMAGE">

  Where "IMAGE" is the buffer name that visits the image file.
・Preview it by `C-c RET P' or send it by `C-c C-c'.

This means that a warning often seen recently

  ‘string-as-unibyte’ is an obsolete function (as of
      26.1); use ‘encode-coding-string’.

does not say the truth, does it?

Thanks.