bug#13540: 24.3.50; Regression in trunk: auto-revert-mode fails on files accessed via samba

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 24 Jan 2013 17:34:46 +0100
> From: Dani Moncayo <dmoncayo@gmail.com>
> Cc: Michael Albinus <michael.albinus@gmx.de>, 13540@debbugs.gnu.org
> 
> > I don't have access to Samba-mounted volumes.
> >
> > Dani, if you attach a debugger to Emacs before evaluating the above
> > expression, do you see any warning messages printed by GDB?  For
> > example, this one:
> >
> >         DebPrint (("watch_worker, abnormal exit: %lu\n", GetLastError ()));
> >
> > If you see any messages, please post them here.
> 
> Mmmm I'm afraid I can't do that, be cause that machine doesn't have
> MinGW and I'm not allowed to install it there.

So you are allowed to bring the Emacs executable there, but not the
GDB executable?  gdb.exe and its dependency DLLs is all you need.

The debugging messages are received by any debugger attached to Emacs,
not just GDB.  So if you have there Windows Debugging Tools, like
WinDbg, you can use that to display those messages.

> Another possibility would be to compile a modified version of Emacs
> which dumps any useful information to a file, for example.

You could redefine the DebPrint macro so that it prints stuff to
stderr.  Then invoke emacs.exe from the shell prompt, not via
runemacs.exe or a desktop icon, and this stuff will go to the shell
window.  (Enlarge the "Screeen Buffer Size Height" in the Properties
of the Command Prompt window to a large number, like 5000, to be able
to see many past messages.)

Without knowing what goes wrong with Samba-mounted volumes, the only
way to deal with this is to customize auto-revert-use-notify to nil,
which will fall back to the old methods of auto-reverting.