ask-user-about-supersession-threat called when autorevert mode is set

[Klaus Zeitler]

Symptoms:

Situation:

I have global-auto-revert-mode turned on in CVS emacs.
Sometimes when emacs tries to autorevert a buffer (e.g. the TAGS buffer while
the tag file is being recreated in a background job) the following question
pops up:
"TAGS changed on disk; really edit the buffer? (y, n, r or C-h)"

I took a glance at revert-buffer and insert-file-contents and it looks to
me as if emacs checks (with verify-visited-file-modtime) file and buffer time
before and after inserting the contents. Now when the file time has again
changed in the meantime (more than 1 sec difference), emacs calls
ask-user-about-supersession-threat.
This happens when I have huge tag (20M and more) or log files in emacs, that
are regenerated in the background. 
I had emacs printing out time stamps in verify-visited-file-modtime
and the times for file and buffer after insert-file-contents differed
up to 4 seconds. 

I've never observed this behaviour in emacs 21.2.


In GNU Emacs 21.3.50.13 (sparc-sun-solaris2.8, Motif Version 2.1.0)
 of 2004-10-11 on sfsws4
configured using `configure '--with-gcc' 
'--prefix=/vol/freeware/SunOS-5.8/emacs/cvs' 
'--sharedstatedir=/vol/freeware/SunOS-5.8/emacs/cvs/share' 
'--with-x-toolkit=motif' 
'--x-includes=/usr/openwin/include:/usr/local/gnu/include' 
'--x-libraries=/usr/openwin/lib:/usr/local/gnu/lib' '--with-pop' 'CC=gcc''

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

Major mode: Lisp Interaction

Minor modes in effect:
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  line-number-mode: t

Recent input:
<help-echo> <help-echo> <menu-bar> <help-menu> <re
port-emacs-bug>

Recent messages:
Loading mwheel...done
(/usr/local/gnu/cvs/head/bin/emacs -q --no-site-file)
Loading tool-bar...done
Loading image...done
Loading tooltip...done
For information about the GNU Project and its goals, type C-h C-p.
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