delete-other-frames

[martin rudalics <rudalics@gmx.at>]

I'd like to fix two issues with ‘delete-other-frames’ but am yet
undecided on how to do that.

(1) With emacs -Q step by step evaluate the following forms:

(setq less (make-frame '((minibuffer . nil))))
(setq normal (make-frame))
(delete-other-frames normal)

This gets me:

Debugger entered--Lisp error: (error "Attempt to delete a surrogate minibuffer frame")
   delete-frame(#<frame *scratch* 01bb1090>)
   delete-other-frames(#<frame *scratch* 050f4a30>)
   eval((delete-other-frames normal) nil)
   elisp--eval-last-sexp(nil)
   eval-last-sexp(nil)
   funcall-interactively(eval-last-sexp nil)
   call-interactively(eval-last-sexp nil nil)
   command-execute(eval-last-sexp)

The problematic code in ‘delete-other-frames’ is this:

     ;; Delete mon-minibuffer-only frames first, because `delete-frame'
     ;; signals an error when trying to delete a mini-frame that's
     ;; still in use by another frame.
     (dolist (frame frames)
       (unless (eq (frame-parameter frame 'minibuffer) 'only)
	(delete-frame frame)))

Here we try to delete all frames whose `minibuffer' parameter is not
`only'.  However, the minibuffer window of a minibuffer-less frame might
be on a _normal_ frame as in our example: The minibuffer window of the
frame ‘less’ is owned by the initial frame and ‘delete-other-frames’
tries to delete that frame before ‘less’, resulting in the error cited
above.

Should we document the current behavior in the doc-string or should we
amend the code?

(2) The doc-string says "Delete all frames on the current terminal,
except FRAME."  IIUC this doesn't make much sense when FRAME is not on
the current terminal.  In that case, ‘delete-other-frames’ will delete
all frames on the current terminal and leave the frames on FRAME's
terminal alone.  In order to delete all other frames on FRAME's terminal
one has to make that terminal current first.  If that is the desired
behavior, we should mention it in the doc-string.  Otherwise, we should
delete all other frames on FRAME's terminal.

Thanks for suggestions, martin