GNU bug report logs - #4560
23.1.50; (string-match "string" nil) error when typing `M-x help RET'

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

From: Giorgos Keramidas <keramida <at> ceid.upatras.gr>
To: emacs-pretest-bug <at> gnu.org
Subject: 23.1.50; (string-match "string" nil) error when typing `M-x help RET'
Date: Sat, 26 Sep 2009 10:52:29 +0300

Something seems to have changed in the way string-match works with its
second argument is nil.  By typing `M-x help RET' I expected to see the
same prompt that is displayed by <f1>, but instead of that a snapshot of
Emacs built from the Git mirror of the repository throws me into the
debugger at:

    Debugger entered--Lisp error: (wrong-type-argument stringp nil)
      string-match("%THIS-KEY%" nil)
      help()
      call-interactively(help t nil)
      execute-extended-command(nil)
      call-interactively(execute-extended-command nil nil)

The last changeset I have in my local Git clone is:

    commit f6829d72c1b405d6c43caa554c2123f41917e358
    Author: Chong Yidong <cyd <at> stupidchicken.com>
    Date:   Fri Sep 25 22:04:07 2009 +0000

        * files.el (safe-local-eval-forms): Allow time-stamp in
        before-save-hook (Bug#4554).

I'm updating a local mirror of the CVS repository now to check if this
is an artifact of the Git mirror.  In the meantime, does this seem like
a bug in `M-x help' or like something we recently changed in the
behavior of `string-match'?

In GNU Emacs 23.1.50.1 (i386-unknown-freebsd9.0, GTK+ Version 2.16.6)
 of 2009-09-26 on kobe
configured using `configure  '--prefix=/opt/emacs' '--with-x' '--with-x-toolkit=gtk' '--with-xpm' '--with-jpeg' '--with-tiff' '--with-gif' '--with-png''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: el_GR.ISO8859-7
  value of $LC_CTYPE: el_GR.ISO8859-7
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: C
  value of $XMODIFIERS: nil
  locale-coding-system: greek-iso-8bit-unix
  default enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  erc-list-mode: t
  erc-menu-mode: t
  erc-button-mode: t
  erc-netsplit-mode: t
  erc-track-mode: t
  erc-track-minor-mode: t
  erc-match-mode: t
  erc-notify-mode: t
  erc-autojoin-mode: t
  erc-services-mode: t
  erc-networks-mode: t
  erc-pcomplete-mode: t
  erc-ring-mode: t
  erc-log-mode: t
  erc-stamp-mode: t
  erc-irccontrols-mode: t
  erc-noncommands-mode: t
  erc-move-to-prompt-mode: t
  erc-readonly-mode: t
  iswitchb-mode: t
  cua-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
RET C-x C-b s a RET C-x b d e m o RET C-x b n u x RET
C-x b d a r k RET C-l C-x b n u x RET C-x b s c r a
RET ESC x t o g g TAB d e b u TAB e TAB RET ESC x h
e l p RET ESC O A ESC [ 1 ; 2 B ESC [ 1 ; 2 B ESC [
1 ; 2 B ESC [ 1 ; 2 B ESC [ 1 ; 2 B ESC [ 1 ; 2 B ESC
[ 1 ; 2 B ESC w C-] RET C-y RET ESC x r e p o r t -
TAB b u TAB RET

Recent messages:
#Linux modes: +nc
#Linux was created on Tuesday 1999/03/30 04:13:13
Updating buffer list...
Formats have changed, recompiling...done
Updating buffer list...done
Commands: m, u, t, RET, g, k, S, D, Q; q to quit; h for help
Debug on Error enabled globally
Entering debugger...
Quit
Mark set

Load-path shadows:
None found.

Message #10 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Giorgos Keramidas <keramida <at> ceid.upatras.gr>
Cc: 4560 <at> debbugs.gnu.org, emacs-pretest-bug <at> gnu.org
Subject: Re: bug#4560: 23.1.50; (string-match "string" nil) error when typing `M-x help RET'
Date: Sat, 26 Sep 2009 20:28:08 -0400

> Something seems to have changed in the way string-match works with its
> second argument is nil.

Actually, the problem was in help.el's use of make-help-screen.
I've installed the patch below, which should fix it,


        Stefan


--- lisp/help.el	14 Sep 2009 23:28:43 -0000	1.348
+++ lisp/help.el	27 Sep 2009 00:27:00 -0000
@@ -203,7 +203,9 @@
 ;; It can't find this, but nobody will look.
 (make-help-screen help-for-help-internal
   (purecopy "Type a help option: [abcCdefFgiIkKlLmnprstvw.] C-[cdefmnoptw] or ?")
-  (purecopy
+  ;; Don't purecopy this one, because it's not evaluated (it's
+  ;; directly used as a docstring in a function definition, so it'll
+  ;; be moved to the DOC file anyway: no need for purecopying it).
   "You have typed %THIS-KEY%, the help character.  Type a Help option:
 \(Use SPC or DEL to scroll through this text.  Type \\<help-map>\\[help-quit] to exit the Help command.)
 
@@ -248,7 +250,7 @@
 C-o         Emacs ordering and distribution information.
 C-p         Info about known Emacs problems.
 C-t         Emacs TODO list.
-C-w         Information on absence of warranty for GNU Emacs.")
+C-w         Information on absence of warranty for GNU Emacs."
   help-map)
 
 

Message #20 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Giorgos Keramidas <keramida <at> ceid.upatras.gr>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: 4560 <at> debbugs.gnu.org, emacs-pretest-bug <at> gnu.org
Subject: Re: bug#4560: 23.1.50; (string-match "string" nil) error when typing `M-x help RET'
Date: Sun, 27 Sep 2009 05:17:57 +0300

On Sat, 26 Sep 2009 20:28:08 -0400, Stefan Monnier <monnier <at> iro.umontreal.ca> wrote:
>> Something seems to have changed in the way string-match works with its
>> second argument is nil.
>
> Actually, the problem was in help.el's use of make-help-screen.
> I've installed the patch below, which should fix it,

> --- lisp/help.el	14 Sep 2009 23:28:43 -0000	1.348
> +++ lisp/help.el	27 Sep 2009 00:27:00 -0000
> @@ -203,7 +203,9 @@
>  ;; It can't find this, but nobody will look.
>  (make-help-screen help-for-help-internal
>    (purecopy "Type a help option: [abcCdefFgiIkKlLmnprstvw.] C-[cdefmnoptw] or ?")
> -  (purecopy
> +  ;; Don't purecopy this one, because it's not evaluated (it's
> +  ;; directly used as a docstring in a function definition, so it'll
> +  ;; be moved to the DOC file anyway: no need for purecopying it).
>    "You have typed %THIS-KEY%, the help character.  Type a Help option:
>  \(Use SPC or DEL to scroll through this text.  Type \\<help-map>\\[help-quit] to exit the Help command.)
>
> @@ -248,7 +250,7 @@
>  C-o         Emacs ordering and distribution information.
>  C-p         Info about known Emacs problems.
>  C-t         Emacs TODO list.
> -C-w         Information on absence of warranty for GNU Emacs.")
> +C-w         Information on absence of warranty for GNU Emacs."
>    help-map)

Thanks!  This seems to have fixed the bug :-)

Message #30 received at 4560-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Giorgos Keramidas <keramida <at> ceid.upatras.gr>
Subject: Re: bug#4560: 23.1.50; (string-match "string" nil) error when typing `M-x help RET'
Date: Sun, 27 Sep 2009 14:56:12 -0400

>>> Something seems to have changed in the way string-match works with its
>>> second argument is nil.
>> Actually, the problem was in help.el's use of make-help-screen.
>> I've installed the patch below, which should fix it,
> Thanks!  This seems to have fixed the bug :-)

Thank you for confirming,


        Stefan

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