bug#59305: 29.0.50; keymap-global-set handling of string bindings different from global-set-key

[Robert Pluim]

`global-set-key' allows you to bind keys to strings (or vectors). The
following all succeed without error (although only [1] and [3] match the
expectations of users unfamiliar with Emacs' key representation).

1. (global-set-key (kbd "C-c h") "hello")
2. (global-set-key (kbd "C-c h") "olá")
3. (global-set-key (kbd "C-c h") (kbd "olá"))

Trying to map this to emacs-29's `keymap-global-set', we get the
following issues

(keymap-global-set "C-c h" "hello") => error
(keymap-global-set "C-c h" "olá") => error

OK, maybe we need to wrap the definitions in `kbd' like [3] above.

(keymap-global-set "C-c h" (kbd "olá")) => definition is a vector -> ok

but
4. (keymap-global-set "C-c h" (kbd "hello")) => defn is a string -> error

After reading up on `key-valid-p':

5. (keymap-global-set "C-c h" "h e l l o") => success!

or alternatively

6. (keymap-global-set "C-c h" [?h ?e ?l ?l ?o]) => success!

Whilst not strictly a regression, this behaviour is confusing and
unhelpful, and the solution is not easily found. I can think of two
solutions:

1. Change `kbd' to always return a vector even if the input is
ascii-only, which makes [4] work
2. Change `keymap-set' to convert ascii-only strings to the format in
[5] or [6]. Probably just a call to `string-to-vector' is enough.

Thanks

Robert

In GNU Emacs 29.0.50 (build 43, x86_64-pc-linux-gnu, GTK+ Version
 3.24.24, cairo version 1.16.0) of 2022-11-16 built on rltb
Repository revision: 60f2bb862f834fcb580d839ac79b30a8b4cd4167
Repository branch: master
System Description: Debian GNU/Linux 11 (bullseye)

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