bug#17873: 24.4.50; `desktop-save'

[Drew Adams <drew.adams@oracle.com>]

1. The doc string says:

 If AUTO-SAVE is non-nil, compare the saved contents to the one last saved,
 and don't save the buffer if they are the same.

Saved contents of what?  One what last saved?  Saved contents cannot be
compared to "the one" anything.

I think you mean "compare the current desktop information to that in the
desktop file."  If you are avoiding saving (because the contents are the
same) then you cannot speak of comparing the "saved contents" - the
contents have not yet been saved.

And what buffer?  This is about saving a desktop in a desktop-file.
There is no notion of a buffer here - at the user level.  The code puts
the desktop info into a buffer (which then might get saved), but that is
implementation-level.

What `desktop-save' does needs to be described at a user level (what,
not how, unless that is important to users).  Just say that if the
desktop information has not changed since it was last saved then the
file is not rewritten.

2. I also have a question about the behavior: Why is writing the
file even when the content is unchanged the default behavior?  Why the
need to specify AUTO-SAVE instead of an optional SAVE-EVEN-IF-NO-CHANGE?
Is this just for backward compatibility?  (Before AUTO-SAVE was
introduced the behavior was to update the file even if the desktop
info was not changed.)

In GNU Emacs 24.4.50.1 (i686-pc-mingw32)
 of 2014-06-17 on ODIEONE
Bzr revision: 117359 monnier@iro.umontreal.ca-20140617193358-2t1nl1te9gc2mqrx
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''