bug#47747: 28.0.50; `eval-defun' may evaluate previous sexp

bug#47747: 28.0.50; `eval-defun' may evaluate previous sexp

[Sebastian Miele]

With emacs -Q, a *scratch* buffer of

  ;; start of buffer
  (error "")
  ;; !!! point somewhere here !!!
  ;; end of buffer

and point where indicated, invoking `eval-defun' (C-M-x) evaluates the
expression (error "").

Expected: An error indicating that there is no top-level form containing
point, or after point.  (From `eval-defun's docstring: "Evaluate the
top-level form containing point, or after point.")

This is also happens in Emacs 27.2.

In GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.28, cairo version 1.17.4)
 of 2021-04-13 built on huette
Repository revision: 6de79542e43ece9a12ebc032c275a6c3fee0b73b
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12010000
System Description: Arch Linux

Configured using:
 'configure --with-x-toolkit=gtk3 --with-mailutils --with-cairo'

Configured features:
ACL CAIRO DBUS FREETYPE GIF GLIB GMP GNUTLS GPM GSETTINGS HARFBUZZ JPEG
JSON LCMS2 LIBOTF LIBSYSTEMD LIBXML2 M17N_FLT MODULES NOTIFY INOTIFY
PDUMPER PNG RSVG SECCOMP SOUND THREADS TIFF TOOLKIT_SCROLL_BARS X11 XDBE
XIM XPM GTK3 ZLIB

Important settings:
  value of $LC_CTYPE: de_DE.UTF-8
  value of $LANG: C
  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 mail-extr emacsbug message rmc puny dired dired-loaddefs
rfc822 mml mml-sec epa derived epg epg-config gnus-util rmail
rmail-loaddefs auth-source cl-seq eieio eieio-core cl-macs
eieio-loaddefs password-cache json map 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 cl-loaddefs
cl-lib sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils
iso-transl 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 tab-bar menu-bar
rfn-eshadow isearch easymenu timer select scroll-bar mouse jit-lock
font-lock syntax font-core term/tty-colors frame minibuffer 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
cl-preloaded nadvice button loaddefs faces cus-face macroexp files
window 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
cairo move-toolbar gtk x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 50702 9549)
 (symbols 48 6499 1)
 (strings 32 18069 1461)
 (string-bytes 1 598156)
 (vectors 16 13126)
 (vector-slots 8 174449 10296)
 (floats 8 23 37)
 (intervals 56 229 0)
 (buffers 992 12))

bug#47747: 28.0.50; `eval-defun' may evaluate previous sexp

[Lars Ingebrigtsen]

Sebastian Miele <sebastian.miele@gmail.com> writes:

> With emacs -Q, a *scratch* buffer of
>
>   ;; start of buffer
>   (error "")
>   ;; !!! point somewhere here !!!
>   ;; end of buffer
>
> and point where indicated, invoking `eval-defun' (C-M-x) evaluates the
> expression (error "").
>
> Expected: An error indicating that there is no top-level form containing
> point, or after point.  (From `eval-defun's docstring: "Evaluate the
> top-level form containing point, or after point.")

If there are no forms after point, it'll eval the form before point --
and it's been that way for as long as I can remember, so I think the doc
string is just wrong here.

Does anybody else have an opinion here?  Would it make sense to have the
command signal an error if there's no forms at or after point?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#47747: 28.0.50; `eval-defun' may evaluate previous sexp

[Lars Ingebrigtsen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> If there are no forms after point, it'll eval the form before point --
> and it's been that way for as long as I can remember, so I think the doc
> string is just wrong here.
>
> Does anybody else have an opinion here?  Would it make sense to have the
> command signal an error if there's no forms at or after point?

Nobody had an opinion, so I updated the doc string to reflect what it
does in Emacs 29.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no