bug#17389: 24.4.50; REGRESSION: extraneous file locking

bug#17389: 24.4.50; REGRESSION: extraneous file locking

[Drew Adams]

With this build I am seeing file locking that prevents two Emacs
sessions from editing the same buffer.  Emacs pops up annoying questions
etc.  Previously, it was only if you tried to save a buffer that Emacs
let you know about possible conflicts.

In Emacs 24.3, emacs -Q:
C-x C-f iii.el
Type some text.  Do not save the buffer.  Do not exit Emacs.

Do the same thing again.  No problem.  Emacs does not annoy you, telling
you in the second session that some other user/session has file iii.el
locked.

Now do the same thing in this build.  You cannot type text into the
second session's iii.el buffer.  You must first answer the (unclear)
question.  This is quite annoying, unnecessary, and counterproductive.



In GNU Emacs 24.4.50.1 (i686-pc-mingw32)
 of 2014-04-29 on ODIEONE
Bzr revision: 117031 monnier@iro.umontreal.ca-20140429151607-qnkgbymwfaj5ut08
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/Devel/emacs/snapshot/trunk
 --enable-checking=yes,glyphs 'CFLAGS=-O0 -g3'
 LDFLAGS=-Lc:/Devel/emacs/lib 'CPPFLAGS=-DGC_MCHECK=1
 -Ic:/Devel/emacs/include''

bug#17389: 24.4.50; REGRESSION: extraneous file locking

[Eli Zaretskii]

> Date: Fri, 2 May 2014 08:15:16 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> 
> With this build I am seeing file locking that prevents two Emacs
> sessions from editing the same buffer.  Emacs pops up annoying questions
> etc.

That's the intended behavior.

> Previously, it was only if you tried to save a buffer that Emacs
> let you know about possible conflicts.

That's not true, this works like that since file locking was ported to
Windows more than a year ago.  I just tried that in a very old build,
and saw exactly what you describe, as expected.

Unless you didn't describe the recipe in enough details, that is.

> In Emacs 24.3, emacs -Q:
> C-x C-f iii.el
> Type some text.  Do not save the buffer.  Do not exit Emacs.
> 
> Do the same thing again.  No problem.  Emacs does not annoy you, telling
> you in the second session that some other user/session has file iii.el
> locked.

Indeed, this is a new feature (on Windows) in Emacs 24.4.  On other
platforms, Emacs behaved like that since a very long time ago.
etc/NEWS tells how to turn this feature off, if you don't want it.

bug#17389: 24.4.50; REGRESSION: extraneous file locking

[Drew Adams]

> Indeed, this is a new feature (on Windows) in Emacs 24.4.  On other
> platforms, Emacs behaved like that since a very long time ago.
> etc/NEWS tells how to turn this feature off, if you don't want it.

That says to customize `create-lockfiles' to nil to disable file
locking.  Not sure what that means.  Will that restore the pre-Emacs
24.4 behavior?  I want Emacs to do exactly what it has done before
in this regard, neither more nor less.

bug#17389: 24.4.50; REGRESSION: extraneous file locking

[Eli Zaretskii]

> Date: Fri, 2 May 2014 08:57:48 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> Cc: 17389@debbugs.gnu.org
> 
> > Indeed, this is a new feature (on Windows) in Emacs 24.4.  On other
> > platforms, Emacs behaved like that since a very long time ago.
> > etc/NEWS tells how to turn this feature off, if you don't want it.
> 
> That says to customize `create-lockfiles' to nil to disable file
> locking.  Not sure what that means.  Will that restore the pre-Emacs
> 24.4 behavior?  I want Emacs to do exactly what it has done before
> in this regard, neither more nor less.

It will restore the previous behavior regarding file locking,
i.e. files you modify will not be locked.  Whether that is what you
want, I don't know, but it should be easy for you to try and see.