bug#75116: [PATCH] Make 'yank-media' autoselect the best media type

[Eli Zaretskii <eliz@gnu.org>]

> From: Ihor Radchenko <yantar92@posteo.net>
> Cc: Eli Zaretskii <eliz@gnu.org>, 75116@debbugs.gnu.org, pinmacs@cas.cat,
>  rpluim@gmail.com
> Date: Mon, 06 Jan 2025 18:33:42 +0000
> 
> Visuwesh <visuweshm@gmail.com> writes:
> 
> >>> >> +    (setq pref-type (and (null noselect)
> >>> >> +                         (funcall yank-media-autoselect-function
> >>> >> +                                  (mapcar #'car all-types))))
> >>> >> +    (cond
> >>> >> +     ;; We have one preferred mime type so use it unconditionally.
> >>> >> +     ((and pref-type (symbolp pref-type))
> >>> >> +      (funcall (cdr (assq pref-type all-types)) pref-type
> >>> >> +               (yank-media--get-selection pref-type)))
> >>> >> +     ;; The user chose to not autoselect and there's just a single type,
> >>> >> +     ;; just call the handler.
> >>> >> +     ((and (null pref-type) (length= all-types 1))
> >>> >> +      (funcall (cdar all-types) (caar all-types)
> >>> >> +               (yank-media--get-selection (caar all-types))))
> >>> >
> >>> > This goes against what the doc string says.  And I think the doc
> >>> > string describes a better behavior: if the user asked not to
> >>> > auto-select, we shouldn't, even if there's just one type available.
> >>> > We should instead ask the user whether to yank that type, because the
> >>> > user could decide she doesn't want that type, even it it's the only
> >>> > one.
> >>> ...
> >>> I want to ensure we are on the same page wrt UI here:
> >>> 
> >>>     User asks to autoselect:
> >>>       1. autoselect-function (a-s-f) returns one media type: we yank it.
> >>
> >> Yes.
> >>
> >>>       2. a-s-f returns multiple media types: we ask the user which one
> >>>          to yank.
> >>
> >> No, we use the first one.
> >
> > Doesn't this mean there is pratically no difference between (1) and (2)?
> > Ihor, is this okay?  Or did you have something else in mind when you
> > asked for the possibility to return multiple types?
> 
> Eli, what exactly do you mean by "user asks to autoselect"?
> AFAIU, autoselect is done by default. User cannot ask for it. User can
> only supply a prefix argument to explicitly disable autoselection.

That's what I mean by "ask": use the default behavior of the command.

Conceptually, it's the same as the paste operation in other
applications: by default, the application decides which of the formats
to use, and if the user wants to choose, he/she needs to pop up a menu
of available formats in some way and select from there.