Subject: bug#44943: 28.0.50; defvar may return INITVALUE and overwrite symbol's value

From: Lars Ingebrigtsen <[email-masked]>
Date: Sun, 29 Nov 2020 12:00:49 +0100

Kazuhiro Ito <[email-masked]> writes:

> When evaluate below codes, I get unexpected result.
>
> (defvar test 1)
>
> -> test
>
> It is expected.
>
> (defvar test 2)
>
> -> 2
>
> It should return 'test'.
>
> (symbol-value 'test)
>
> -> 2
>
> It should return 1.

When you say "evaluate", what do you mean?  Doing `C-x C-e' after the
form?  If it's the latter, then the doc string explains what's
happening (and this is new behaviour in Emacs 28):

----

C-x C-e runs the command eval-last-sexp (found in global-map), which
is an interactive compiled Lisp function in ‘elisp-mode.el’.

It is bound to C-x C-e.

(eval-last-sexp EVAL-LAST-SEXP-ARG-INTERNAL)

  Probably introduced at or before Emacs version 24.4.

Evaluate sexp before point; print value in the echo area.
Interactively, with a non ‘-’ prefix argument, print output into
current buffer.

This commands handles ‘defvar’, ‘defcustom’ and ‘defface’ the
same way that ‘eval-defun’ does.  See the doc string of that
function for details.

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