bug#37352: 27.0.50; recursive-edit aborts on elisp error after evaluation

[Jean Louis <bugs@gnu.support>]

In my opinion this should not be happening. If I am editing buffer
with recursive-edit the buffer is to abort on Emacs Lisp evaluation if
there is any error taking place.

I am using this function below.

(defun read-from-buffer (value &optional buffer-name mode)
  "Edits string and returns it"
  (let ((this-buffer (buffer-name))
	(new-value value)
	(buffy (if buffer-name buffer-name "*edit-string*")))
    (save-excursion
      (switch-to-buffer buffy)
      (set-buffer buffy)
      (if mode (funcall mode)
	(text-mode))
      (setq header-line-format "➜ Finish editing with C-c C-c or C-M-c")
      (local-set-key (kbd "C-c C-c") 'exit-recursive-edit)
      (if (stringp value) (insert value))
      ;; (speak "You may quit the buffer with Control C Control C")
      (message "When you're done editing press C-c C-c or C-M-c to continue.")
      (unwind-protect
	  (recursive-edit)
	(if (get-buffer-window buffy)
	    (progn
	      (setq new-value (buffer-substring (point-min) (point-max)))
	      (kill-buffer buffy))))
      (switch-to-buffer this-buffer)
      new-value)))

Then you could edit some string to see how this is happening:

(read-from-buffer "EDIT ME\nEvaluate this: (nonexistingfunction) ")

Then there after you could evaluate some non existing function to invoke
the Emacs Lisp error.

At that time the editing with recursive-buffer is interrupted and data
is lost.

This should not happen, as evaluations are often required during editing.





In GNU Emacs 27.0.50 (build 5, x86_64-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2019-09-07 built on protected.rcdrun.com
Repository revision: 40eb4c51a40a37c14e882e6db3f880ba4528c089
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.11906000
System Description: Hyperbola GNU/Linux-libre

Recent messages:
Back to top level
funcall-interactively: No recursive edit is in progress
Mark saved where search started
read-from-buffer
When you’re done editing press C-c C-c or C-M-c to continue.
Entering debugger...
Back to top level
Quit
Mark set
Making completion list...

Configured using:
 'configure --prefix=/package/text/emacs-2019-09-07 --with-modules
 --without-gpm --with-x-toolkit=lucid
 PKG_CONFIG_PATH=/home/data1/protected/GNUstep/Library/Libraries/pkgconfig:/usr/lib/pkgconfig'

Configured features:
XAW3D XPM JPEG TIFF GIF PNG RSVG SOUND DBUS GSETTINGS GLIB NOTIFY
INOTIFY ACL GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS LUCID X11 XDBE XIM MODULES THREADS JSON PDUMPER
LCMS2 GMP

Important settings:
  value of $LC_ALL: de_DE.UTF-8
  value of $LANG: de_DE.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort hashcash mail-extr emacsbug message rmc puny dired
dired-loaddefs format-spec rfc822 mml mml-sec password-cache epa derived
epg epg-config gnus-util rmail rmail-loaddefs text-property-search
time-date subr-x seq byte-opt gv bytecomp byte-compile cconv mm-decode
mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader
sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils
misearch multi-isearch help-fns radix-tree cl-print debug backtrace
help-mode easymenu find-func edmacro kmacro cl-loaddefs cl-lib tooltip
eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel
term/x-win x-win term/common-win x-dnd tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode
lisp-mode prog-mode register page menu-bar rfn-eshadow isearch timer
select scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote threads dbusbind inotify lcms2 dynamic-setting
system-font-setting font-render-setting x-toolkit x multi-tty
make-network-process emacs)

Memory information:
((conses 16 51823 7026)
 (symbols 48 6698 1)
 (strings 32 18378 2144)
 (string-bytes 1 589184)
 (vectors 16 11030)
 (vector-slots 8 142630 10478)
 (floats 8 26 76)
 (intervals 56 382 0)
 (buffers 992 14))

-- 
Thanks,
Jean Louis