GNU bug report logs - #2966
23.0.92; A typing error in debugger-eval-expression stops the debugger

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Message #5 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Daniel Clemente <dcl441-bugs <at> yahoo.com>
To: emacs-pretest-bug <at> gnu.org
Subject: 23.0.92; A typing error in debugger-eval-expression stops the debugger
Date: Sat, 11 Apr 2009 19:01:47 -0700 (PDT)

  Eval anything with (debug) on it, like:

(let* ((x 3) (y 1))
(debug)
(dotimes (a x) (setq y (* y x)))
y
)

  When the debugger appears, press e to evaluate some symbol. You can type x RET to see the value of x. But now try a symbol which doesn't exist, for instance z. You get:

Debugger entered--Lisp error: (void-variable z)
  eval(z)
  eval-expression(z)
  debugger-eval-expression(z)
  call-interactively(debugger-eval-expression nil nil)
  recursive-edit()


  And at this point, your debugger session is (apparently) lost and you can't continue debugging your program: e.g. "c" doesn't work and it only says (error "Cannot return from the debugger in an error")
  It is very annoying that Emacs makes you restart debugging just because you did a typing error in a very infortunate moment. Even if there is some way to get out of this „error inside the evaluated expression“, the default behaviour is shocking.

  Can't errors like void-variable / void-function be ignored by default in debugger-mode?


-- Daniel

Message #14 received at 2966 <at> debbugs.gnu.org (full text, mbox):

From: Lars Magne Ingebrigtsen <larsi <at> gnus.org>
To: dcl441-bugs <at> yahoo.com
Cc: 2966 <at> debbugs.gnu.org
Subject: Re: 23.0.92;
	A typing error in debugger-eval-expression stops the debugger
Date: Fri, 16 Sep 2011 22:24:32 +0200

Daniel Clemente <dcl441-bugs <at> yahoo.com> writes:

>   Eval anything with (debug) on it, like:
>
> (let* ((x 3) (y 1))
> (debug)
> (dotimes (a x) (setq y (* y x)))
> y
> )
>
>   When the debugger appears, press e to evaluate some symbol. You can
> type x RET to see the value of x. But now try a symbol which doesn't
> exist, for instance z. You get:
>
> Debugger entered--Lisp error: (void-variable z)
>   eval(z)
>   eval-expression(z)
>   debugger-eval-expression(z)
>   call-interactively(debugger-eval-expression nil nil)
>   recursive-edit()
>
>   And at this point, your debugger session is (apparently) lost and
> you can't continue debugging your program: e.g. "c" doesn't work and
> it only says (error "Cannot return from the debugger in an error")

This was marked as notabug wontfix, but it's apparently been fixed
anyway.  :-)

You now get a further bug and your environment isn't lost:

Debugger entered--Lisp error: (void-variable z)
  eval(z nil)
  eval-expression(z nil)
  call-interactively(eval-expression nil nil)
  recursive-edit()
  debug()
  eval((debug) nil)
  eval-expression((debug) nil)
  call-interactively(eval-expression nil nil)


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

Message #15 received at 2966-done <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Lars Magne Ingebrigtsen <larsi <at> gnus.org>
Cc: dcl441-bugs <at> yahoo.com, 2966-done <at> debbugs.gnu.org
Subject: Re: bug#2966: 23.0.92;
	A typing error in debugger-eval-expression stops the debugger
Date: Fri, 16 Sep 2011 16:57:18 -0400

>> And at this point, your debugger session is (apparently) lost and
>> you can't continue debugging your program: e.g. "c" doesn't work and
>> it only says (error "Cannot return from the debugger in an error")
> This was marked as notabug wontfix, but it's apparently been fixed
> anyway.  :-)

Indeed I fixed it a few months ago.


        Stefan

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