Subject: Re: bug#15767: closed (Re: bug#15767: 24.3; [patch] electric-indent-mode bug)

From: Dave Abrahams <[email-masked]>
Date: Mon, 4 Nov 2013 21:06:33 -0800

On Nov 4, 2013, at 12:05 PM, GNU bug Tracking System <[email-masked]> wrote:

> Your bug report
> 
> #15767: 24.3; [patch] electric-indent-mode bug
> 
> which was filed against the emacs package, has been closed.
> 
> The explanation is attached below, along with your original report.
> If you require more details, please reply to [email-masked].
> 
> -- 
> 15767: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=15767
> GNU Bug Tracking System
> Contact [email-masked] with problems
> 
> From: Stefan Monnier <[email-masked]>
> Subject: Re: bug#15767: 24.3; [patch] electric-indent-mode bug
> Date: November 4, 2013 at 12:04:31 PM PST
> To: Dave Abrahams <[email-masked]>
> Cc: [email-masked]
> 
> 
>>  (electric-indent-mode)
>>  (electric-layout-mode)
>>  (setq electric-indent-chars (append "{}" electric-indent-chars))
>>  (setq electric-layout-rules '((?\{ . after) (?\} . before)))
> 
>> 3. type `f o o SPC {'
> 
> Thanks.  Your patch defeated a useful case, so I replaced it with the
> one below,

Well, the problem I see is that you left the call to line-beginning-position where it was in the original call.  At that point, point may be on a different line than it started on, so it’s actually getting information about the wrong line.  It’s possible that your patch somehow makes everything work out, but leaving the call to line-beginning-position where it is seems at best fragile to me.
 
> 
>        Stefan
> 
> 
> --- lisp/electric.el	2013-10-07 18:51:26 +0000
> +++ lisp/electric.el	2013-11-04 20:01:20 +0000
> @@ -251,9 +251,10 @@
>             ;; whereas we need `move after insertion', so we do the
>             ;; save/restore by hand.
>             (goto-char before)
> +	    (when (eolp)
>             ;; Remove the trailing whitespace after indentation because
>             ;; indentation may (re)introduce the whitespace.
> -            (delete-horizontal-space t))))
> +	      (delete-horizontal-space t)))))
>       (unless (or (memq indent-line-function '(indent-to-left-margin))
>                   (and electric-indent-inhibit
>                        (> pos (line-beginning-position))))
> 
> 
> 
> 
> From: Dave Abrahams <[email-masked]>
> Subject: 24.3; [patch] electric-indent-mode bug
> Date: October 30, 2013 at 4:03:34 PM PDT
> To: [email-masked]
> 
> 
> 
> 1. emacs -Q
> 2. eval the following:
> 
>  (electric-indent-mode)
>  (electric-layout-mode)
>  (setq electric-indent-chars (append "{}" electric-indent-chars))
>  (setq electric-layout-rules '((?\{ . after) (?\} . before)))
> 
> 3. type `f o o {'
> 
> Result expected: a buffer containing
> ----- schnipp -----
> foo {
> 
> ----- schnapp -----
> 
> Result received: a buffer containing
> ----- schnipp -----
> foo{
> 
> ----- schnapp -----
> 
> Patch is enclosed that fixes the problem.
> 
> 
> diff --git a/lisp/electric.el b/lisp/electric.el
> index 58b8e10..e4257b2 100644
> --- a/lisp/electric.el
> +++ b/lisp/electric.el
> @@ -212,7 +212,7 @@ point right after that char, and it should return t to cause indentation,
>   ;; electric-pair-mode wrapping a region with a pair of parens.
>   ;; There might be a way to get it working by analyzing buffer-undo-list, but
>   ;; it looks challenging.
> -  (let (pos)
> +  (let (pos line-beginning-pos)
>     (when (and
>            electric-indent-mode
>            ;; Don't reindent while inserting spaces at beginning of line.
> @@ -221,6 +221,7 @@ point right after that char, and it should return t to cause indentation,
>            (setq pos (electric--after-char-pos))
>            (save-excursion
>              (goto-char pos)
> +             (setq line-beginning-pos (line-beginning-position))
>              (let ((act (or (run-hook-with-args-until-success
>                              'electric-indent-functions
>                              last-command-event)
> @@ -231,7 +232,7 @@ point right after that char, and it should return t to cause indentation,
>                     (unless (eq act 'do-indent) (nth 8 (syntax-ppss))))))))
>       ;; For newline, we want to reindent both lines and basically behave like
>       ;; reindent-then-newline-and-indent (whose code we hence copied).
> -      (when (< (1- pos) (line-beginning-position))
> +      (when (< (1- pos) line-beginning-pos)
>         (let ((before (copy-marker (1- pos) t)))
>           (save-excursion
>             (unless (memq indent-line-function
> 
> 
> 
> In GNU Emacs 24.3.1 (x86_64-apple-darwin11.4.2, Carbon Version 1.6.0 AppKit 1138.51)
> of 2013-10-27 on Yukikaze.local
> Windowing system distributor `Apple Inc.', version 10.9.0
> Configured using:
> `configure '--with-mac'
> '--enable-mac-app=/Users/xin/Documents/emacs-mac-port/build'
> '--prefix=/Users/xin/Documents/emacs-mac-port/build''
> 
> Important settings:
>  locale-coding-system: utf-8-unix
>  default enable-multibyte-characters: t
> 
> Major mode: Emacs-Lisp
> 
> Minor modes in effect:
>  electric-layout-mode: t
>  electric-pair-mode: t
>  electric-indent-mode: t
>  shell-dirtrack-mode: t
>  recentf-mode: t
>  diff-auto-refine-mode: t
>  global-auto-complete-mode: t
>  auto-complete-mode: t
>  override-global-mode: t
>  workgroups-mode: t
>  nxhtml-menu-mode: t
>  yas-global-mode: t
>  yas-minor-mode: t
>  me-minor-mode: t
>  which-function-mode: t
>  show-paren-mode: t
>  server-mode: t
>  global-auto-revert-mode: t
>  display-time-mode: t
>  delete-selection-mode: t
>  tooltip-mode: t
>  mac-mouse-wheel-mode: t
>  menu-bar-mode: t
>  file-name-shadow-mode: t
>  global-font-lock-mode: t
>  font-lock-mode: t
>  auto-composition-mode: t
>  auto-encryption-mode: t
>  auto-compression-mode: t
>  line-number-mode: t
>  transient-mark-mode: t
> 
> Recent input:
> C-e C-p C-p C-p C-p C-p C-p C-p C-p C-p C-b SPC l i 
> n e - b e g g <backspace> i n - p o s C-b C-b C-b C-b 
> i n g b b <backspace> <backspace> <backspace> <backspace> 
> <backspace> <backspace> n n i n g C-n C-e C-p C-e C-, 
> C-, C-, C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
> C-n C-n C-n C-n C-n C-n C-n C-e C-n C-b C-SPC C-, C-, 
> C-, C-b M-w C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p 
> C-p C-p C-p C-p C-p C-p C-p C-e C-n C-n C-n C-n C-n 
> C-n C-e <return> <tab> ( s e t q SPC l i n e - b e 
> M-/ SPC C-y C-e C-n C-n C-n C-n C-n C-n C-n C-n C-n 
> C-n C-n C-, C-, C-, <backspace> C-. C-. C-. C-d <backspace> 
> <backspace> <backspace> <backspace> <backspace> C-x 
> C-s C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
> C-n C-n C-n C-n C-n C-n C-n C-n C-n C-e C-p C-p C-e 
> C-n C-x C-e <C-return> C-p C-e C-n <backspace> <backspace> 
> <backspace> <backspace> SPC { <C-return> C-SPC C-p 
> C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p C-p 
> C-p C-g C-g C-g M-! g i t SPC d i f f <return> <C-return> 
> C-s e l e C-p C-n C-n C-s e l e c t r i c C-a C-SPC 
> C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
> C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n C-n 
> C-n C-n C-n C-n M-w <C-return> C-x C-b C-x C-b M-x 
> e m a v <backspace> c - <backspace> <backspace> <backspace> 
> <backspace> <backspace> <backspace> r e p o r t - e 
> m <tab> <return>
> 
> Recent messages:
> Mark set
> Saving file /Users/dave/src/emacs-mac-port/lisp/electric.el...
> Wrote /Users/dave/src/emacs-mac-port/lisp/electric.el
> electric-indent-post-self-insert-function
> Mark set
> Quit [3 times]
> Mark saved where search started [2 times]
> Mark set
> delete-backward-char: Text is read-only
> Loading /Users/dave/.emacs.d/el-get/dwamacs/settings/message-settings.el (source)...done
> 
> Load-path shadows:
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> /Users/dave/.emacs.d/el-get/nxhtml/related/csharp-mode hides /Users/dave/.emacs.d/el-get/csharp-mode/csharp-mode
> /Users/dave/.emacs.d/el-get/cedet/lisp/speedbar/loaddefs hides /Users/dave/.emacs.d/el-get/cedet/lisp/eieio/loaddefs
> /Users/dave/.emacs.d/el-get/cedet/lisp/speedbar/loaddefs hides /Users/dave/.emacs.d/el-get/cedet/lisp/cedet/loaddefs
> /Users/dave/.emacs.d/el-get/magit/.dir-locals hides /Users/dave/.emacs.d/el-get/el-get/.dir-locals
> /Users/dave/.emacs.d/el-get/cedet/lisp/speedbar/loaddefs hides /Applications/Emacs.app/Contents/Resources/lisp/loaddefs
> /Users/dave/.emacs.d/el-get/dwamacs/site-lisp/ediff-util hides /Applications/Emacs.app/Contents/Resources/lisp/vc/ediff-util
> /Users/dave/.emacs.d/el-get/python/python hides /Applications/Emacs.app/Contents/Resources/lisp/progmodes/python
> /Users/dave/.emacs.d/el-get/dwamacs/site-lisp/compile hides /Applications/Emacs.app/Contents/Resources/lisp/progmodes/compile
> /Users/dave/.emacs.d/el-get/nxhtml/util/org-odt hides /Applications/Emacs.app/Contents/Resources/lisp/org/org-odt
> /Users/dave/.emacs.d/el-get/magit/.dir-locals hides /Applications/Emacs.app/Contents/Resources/lisp/gnus/.dir-locals
> /Users/dave/.emacs.d/el-get/dwamacs/site-lisp/ert hides /Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/ert
> /Users/dave/.emacs.d/el-get/dwamacs/site-lisp/ert-x hides /Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/ert-x
> /Users/dave/.emacs.d/el-get/cedet/lisp/eieio/eieio hides /Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/eieio
> /Users/dave/.emacs.d/el-get/cedet/lisp/eieio/eieio-speedbar hides /Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/eieio-speedbar
> /Users/dave/.emacs.d/el-get/cedet/lisp/eieio/eieio-opt hides /Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/eieio-opt
> /Users/dave/.emacs.d/el-get/cedet/lisp/eieio/eieio-datadebug hides /Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/eieio-datadebug
> /Users/dave/.emacs.d/el-get/cedet/lisp/eieio/eieio-custom hides /Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/eieio-custom
> /Users/dave/.emacs.d/el-get/cedet/lisp/eieio/eieio-base hides /Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/eieio-base
> /Users/dave/.emacs.d/el-get/cedet/lisp/eieio/chart hides /Applications/Emacs.app/Contents/Resources/lisp/emacs-lisp/chart
> 
> Features:
> (shadow sort mail-extr emacsbug message format-spec rfc822 mml mml-sec
> mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
> mailheader sendmail rfc2047 rfc2045 ietf-drums mail-utils debug pcase
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> password-cache url-vars auto-complete-config auto-complete popup
> use-package bind-key session-settings session system-type-darwin-theme
> osx-plist xml .loaddefs workgroups flymake-files flymakemsg
> nxhtml-autostart nxhtml-autoload majmodpri vc-git nxhtml-menu
> web-autoload nxhtml-base helm-config helm-aliases fill-column-indicator
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> srecode/compile srecode/dictionary srecode/table srecode
> semantic/canned-configs semantic/ia-sb semantic/analyze semantic/sort
> semantic/scope semantic/analyze/fcn semantic/db semantic/ctxt
> semantic/format semantic/tag-ls semantic/find semantic/util-modes
> semantic/util semantic semantic/tag semantic/lex semantic/fw mode-local
> cedet-compat inversion ede/speedbar ede/files ede ede/base ede/auto
> ede/source eieio-base eieio-speedbar speedbar sb-image ezimage dframe
> eieio-custom wid-edit cedet eieio byte-opt eieio-core
> cedet-remove-builtin yasnippet advice advice-preload dropdown-list
> derived edmacro kmacro el-get el-get-autoloads el-get-list-packages
> el-get-notify help-mode el-get-dependencies el-get-build el-get-status
> pp el-get-recipes el-get-byte-compile el-get-methods el-get-fossil
> el-get-svn el-get-pacman el-get-github-zip el-get-github-tar
> el-get-http-zip el-get-http-tar el-get-hg el-get-git-svn el-get-fink
> el-get-emacswiki el-get-http el-get-emacsmirror el-get-github el-get-git
> el-get-elpa package cl-macs gv el-get-darcs el-get-cvs el-get-bzr
> el-get-brew el-get-builtin el-get-apt-get el-get-custom el-get-core
> autoload help-fns bytecomp byte-compile cconv cl cl-lib dired-x easymenu
> dired easy-mmode which-func imenu paren server ido autorevert time
> delsel cus-start cus-load elhome time-date tooltip ediff-hook vc-hooks
> lisp-float-type mwheel mac-win tool-bar dnd fontset image regexp-opt
> fringe tabulated-list newcomment lisp-mode register page menu-bar
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> env code-pages mule custom widget hashtable-print-readable backquote mac
> multi-tty make-network-process emacs)
> 
>