bug#29107: 27.0.50; Infinite recursion in Ruby mode

bug#29107: 27.0.50; Infinite recursion in Ruby mode

[Anders Lindgren]

[-- Attachment #1: Type: text/plain, Size: 3779 bytes --]

Hi!

I just noticed that Ruby mode can go into infinite recursion (or "Lisp
nesting exceeds ‘max-lisp-eval-depth’"). I managed to boil it down to the
following:

    Evaluate (setq debug-on-error t)

    Open a new file, say test.rb
    Type:

        func do {

    And press return.

In the backtrace, the following is listed over and over again:

  ruby-smie--indent-to-stmt()
  ruby-smie-rules(:before "{")
  smie-indent--rule-1(:before "{" nil nil)
  smie-indent--rule(:before "{")
  smie-indent-keyword()
  run-hook-with-args-until-success(smie-indent-keyword)
  smie-indent-calculate()
  smie-indent-virtual()

It happens in Emacs 25.2 and in a week-old build from the master branch.

Sincerely,
    Anders Lindgren

In GNU Emacs 27.0.50 (build 2, x86_64-apple-darwin16.6.0, NS appkit-1504.83
Version 10.12.5 (Build 16F73))
 of 2017-10-25 built on mbp.lan
Repository revision: bc9300ac5ed3bdf52a2f8b9e217236e1ee76cd02
Windowing system distributor 'Apple', version 10.3.1504
Recent messages:
t
(New file)
Mark set
s-( is undefined
Mark set
Entering debugger...
Error in debug printer: (void-function t) [1113 times]
Error during redisplay: (ucs-normalize-hfs-nfd-pre-write-conversion 1 92)
signaled (error "Variable binding depth exceeds max-specpdl-size") [2 times]
set-auto-coding: Variable binding depth exceeds max-specpdl-size
Back to top level

Configured features:
JPEG NOTIFY ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS NS

Important settings:
  value of $LC_CTYPE: UTF-8
  value of $LANG: en_SE.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Special

Minor modes in effect:
  tooltip-mode: t
  global-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
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny seq byte-opt dired
dired-loaddefs format-spec rfc822 mml mml-sec password-cache epa derived
epg epg-config gnus-util rmail rmail-loaddefs mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils help-mode
warnings gv bytecomp byte-compile cl-loaddefs cl-lib cconv debug
vc-dispatcher vc-svn ruby-mode smie easymenu elec-pair time-date tooltip
eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel
term/ns-win ns-win ucs-normalize mule-util term/common-win tool-bar dnd
fontset image regexp-opt fringe tabulated-list replace newcomment
text-mode elisp-mode lisp-mode prog-mode register page menu-bar
rfn-eshadow isearch timer select scroll-bar mouse jit-lock font-lock
syntax facemenu font-core term/tty-colors frame 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 minibuffer
cl-preloaded nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote kqueue cocoa ns
multi-tty make-network-process emacs)

Memory information:
((conses 16 209217 10912)
 (symbols 48 20615 1)
 (miscs 40 57 249)
 (strings 32 30746 1897)
 (string-bytes 1 808845)
 (vectors 16 35813)
 (vector-slots 8 721700 15012)
 (floats 8 49 266)
 (intervals 56 218 0)
 (buffers 992 14))

[-- Attachment #2: Type: text/html, Size: 4986 bytes --]

bug#29107: 27.0.50; Infinite recursion in Ruby mode

[Noam Postavsky]

tags 29107 + confirmed
quit

Anders Lindgren <andlind@gmail.com> writes:

> I just noticed that Ruby mode can go into infinite recursion (or
> "Lisp nesting exceeds ‘max-lisp-eval-depth’"). I managed to boil it
> down to the following:
>
>     Evaluate (setq debug-on-error t)
>
>     Open a new file, say test.rb
>     Type:
>
>         func do {
>
>     And press return.



> Entering debugger...
> Error in debug printer: (void-function t) [1113 times]

By the way, this funny message seems to be caused by loading cl-print
while stack has been used up by the inf looping.  If setting
debugger-print-function to prin1, or loading cl-print before triggering
the bug, that message doesn't show up.

bug#29107: 27.0.50; Infinite recursion in Ruby mode

[Dmitry Gutov]

Version: 28.1

Hi Anders,

On 01.11.2017 21:52, Anders Lindgren wrote:
> I just noticed that Ruby mode can go into infinite recursion (or "Lisp 
> nesting exceeds ‘max-lisp-eval-depth’"). I managed to boil it down to 
> the following:
> 
>      Evaluate (setq debug-on-error t)
> 
>      Open a new file, say test.rb
>      Type:
> 
>          func do {
> 
>      And press return.
> 
> In the backtrace, the following is listed over and over again:
> 
>    ruby-smie--indent-to-stmt()
>    ruby-smie-rules(:before "{")
>    smie-indent--rule-1(:before "{" nil nil)
>    smie-indent--rule(:before "{")
>    smie-indent-keyword()
>    run-hook-with-args-until-success(smie-indent-keyword)
>    smie-indent-calculate()
>    smie-indent-virtual()
> 
> It happens in Emacs 25.2 and in a week-old build from the master branch.

Sorry about the long wait, it didn't seem like a critical issue given 
that the code in question was either a typo, or a very weird way to 
write a block. Please correct me if I'm wrong here.

Either way, it should be fixed now in master, commit 0f561ee553.