bug#73568: 30.0.91; which-key error in speedbar (wrong-type-argument wholenump -13)

[Stefan Kangas <stefankangas@gmail.com>]

Morgan Willcock <morgan@ice9.digital> writes:

> An error is signalled when which-key is activated, point is within the
> speedbar frame, and a portion of a key-sequence has been typed
> (e.g. C-x).
>
> To generate an example backtrace:
>
>   emacs -Q \
>       --eval "(which-key-mode)" \
>       --eval "(speedbar-get-focus)" \
>       --eval "(toggle-debug-on-error)" \
>       --eval "(setq unread-command-events (listify-key-sequence \"\C-x\"))"

Here's the error I get:

Debugger entered--Lisp error: (wrong-type-argument wholenump -14)
  make-string(-14 32)

The problem occurs is in `which-key--pad-column': the speedbar frame is
only 14 characters wide, and so can't fit longer strings than that.

I actually see two bugs here:

1. Create a regular Emacs frame of width 14, enable `which-key-mode' and
   press some key, e.g. C-h.  You now get a similar backtrace.  Probably
   `which-key' should simply be smarter in this case, for example by
   truncating instead of padding.

2. With a dframe, as in speedbar, I guess `which-key' should try to
   display it's help window in the original frame?

I'm copying in Justin Burkett.