bug#982: 23.0.60; file-truename causes an error.

bug#982: 23.0.60; file-truename causes an error.

[TAKAHASHI Yoshio]

I have a file "c:/tmp/a.txt", but don't have "c:/tmp/b.txt".

(pwd)
"Directory c:/tmp/"

(w32-long-file-name "/tmp/a.txt")
"c:/tmp/a.txt"

(file-truename "./a.txt")
"c:/tmp/a.txt"

(file-truename "a.txt")
"c:/tmp/a.txt"

(w32-long-file-name "/tmp/b.txt")
nil

(file-truename "./b.txt")
"c:/tmp/b.txt"

(file-truename "b.txt")
Debugger entered--Lisp error: (args-out-of-range "b.txt" 0 -1)
  substring("b.txt" 0 -6)
  (setq rest (substring filename 0 (* -1 ...)))


From files.el:

(defun file-truename (filename &optional counter prev-dirs)
  ...
                (setq missing (concat "/" (file-name-nondirectory filename)))
                (setq rest (substring filename 0 (* -1 (length missing))))
  ...

When FILENAME has no directory separator, MISSING is one char longer
than FILENAME.  In this case, substring raises an out-of-range error.




Please write in English if possible, because the Emacs maintainers
usually do not have translators to read other languages for them.

Your bug report will be posted to the emacs-pretest-bug@gnu.org mailing list.

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:



If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
If you would like to further debug the crash, please read the file
c:/opt/emacs/23.0.60/etc/DEBUG for instructions.


In GNU Emacs 23.0.60.1 (i386-mingw-nt5.1.2600)
 of 2008-09-15 on HIBARI
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (3.4) --cflags -I/gnuwin32/include'

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: C
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: JPN
  value of $XMODIFIERS: nil
  locale-coding-system: cp932
  default-enable-multibyte-characters: t

Major mode: Lisp Interaction

Minor modes in effect:
  tooltip-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<help-echo> <help-echo> <help-echo> <help-echo> <help-echo> 
<menu-bar> <help-menu> <send-emacs-bug-report>

Recent messages:
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bug#982: 23.0.60; file-truename causes an error

[martin rudalics]

 > I have a file "c:/tmp/a.txt", but don't have "c:/tmp/b.txt".
 > [...]
 > (file-truename "./b.txt")
 > "c:/tmp/b.txt"
 >
 > (file-truename "b.txt")
 > Debugger entered--Lisp error: (args-out-of-range "b.txt" 0 -1)
 >   substring("b.txt" 0 -6)
 >   (setq rest (substring filename 0 (* -1 ...)))
 >
 >
 > From files.el:
 >
 > (defun file-truename (filename &optional counter prev-dirs)
 >   ...
 >                 (setq missing (concat "/" (file-name-nondirectory filename)))
 >                 (setq rest (substring filename 0 (* -1 (length missing))))
 >   ...
 >
 > When FILENAME has no directory separator, MISSING is one char longer
 > than FILENAME.  In this case, substring raises an out-of-range error.

I've checked in a fix which should remove the args-out-of-range error.
Please try it since I'm not sure whether the directory part should be
handled better.

Thanks for reporting, martin.