[Bug-AUCTeX] 11.87; TeX-evince-sync-view confuses window managers with bad timestamps

[Reuben Thomas]

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------------------------------------------------------------------------

I've just tracked down a really bizarre window manager problem to
TeX-evince-sync-view: I noticed that when launching evince using this
command (and only then), Alt+Tab stopped working on my GNOME 3 desktop.
I discovered by instrumenting the Alt+Tab extension I use that this was
because Mutter (the Window manager) was confused by a timestamp on an X
event that was much larger than the current X clock time (which is ms
since X server was started). To cut a long story short, I finally
discovered that the time value in the bogus time stamps was "the same"
as that produced by float-time. This explains why I only had the problem
on one machine out of two: on the other one, the X server timestamps
were bigger numbers than the real time in seconds, because the X server
had been running sufficiently long.

There's a comment in the code that says:

                   ;; FIXME: Evince wants a timestamp as UInt32, but POSIX time
                   ;; is too large for emacs integers on 32 bit systems.  Emacs
                   ;; 24.2 will allow providing DBUS ints as floats, and this
                   ;; dbus version will be identifiable by its new variables
                   ;; `dbus-compiled-version' and `dbus-runtime-version'.  But
                   ;; it seems providing just 1 as timestamp has no negative
                   ;; consequences, anyway.

As far as I can tell, the first part is incomplete: the timestamp
required is specifically an X timestamp, as something (Evince? DBus?)
uses it to set the timestamp of an X event (at least, when Emacs and
Evince are running on X). However, the second part gives a solution: if
I change the code so that it always passes 1 as the timestamp,
everything works fine, because the first time the WM examines the
window, it updates the timestamp to the current time (whereas when it
finds a timestamp in the future it cautiously invokes some workaround,
with the result that things stop working).

There are obviously things going on here that I don't understand (I know
nothing about X, DBus, or Evince internals), but all I can say is that
the time argument is definitely being bogusly used as an X timestamp,
which causes really weird behavior, and that passing 1 instead seems, as
intimated by the comment, to cause no problem whatsoever.

Emacs  : GNU Emacs 24.1.1 (x86_64-pc-linux-gnu, GTK+ Version 2.24.12)
 of 2012-09-22 on batsu, modified by Debian
Package: 11.87

current state:
==============
(setq
 AUCTeX-date "2012-11-30"
 window-system 'x
 LaTeX-version "2e"
 TeX-style-path '("/var/lib/auctex/emacs24/" 
"/usr/share/emacs/site-lisp/auctex/style"
                  "/home/rrt/.emacs.d/auctex/auto" 
"/home/rrt/.emacs.d/auctex/style" "auto"
                  "style")
 TeX-auto-save nil
 TeX-parse-self nil
 TeX-master t
 TeX-command-list '(("TeX" "%(PDF)%(tex) %`%S%(PDFout)%(mode)%' %t" TeX-run-TeX 
nil
                     (plain-tex-mode texinfo-mode ams-tex-mode) :help "Run 
plain TeX")
                    ("LaTeX" "%`%l%(mode)%' %t" TeX-run-TeX nil (latex-mode 
doctex-mode) :help
                     "Run LaTeX")
                    ("Makeinfo" "makeinfo %t" TeX-run-compile nil 
(texinfo-mode) :help
                     "Run Makeinfo with Info output")
                    ("Makeinfo HTML" "makeinfo --html %t" TeX-run-compile nil 
(texinfo-mode)
                     :help "Run Makeinfo with HTML output")
                    ("AmSTeX" "%(PDF)amstex %`%S%(PDFout)%(mode)%' %t" 
TeX-run-TeX nil
                     (ams-tex-mode) :help "Run AMSTeX")
                    ("ConTeXt" "texexec --once --texutil %(execopts)%t" 
TeX-run-TeX nil
                     (context-mode) :help "Run ConTeXt once")
                    ("ConTeXt Full" "texexec %(execopts)%t" TeX-run-TeX nil 
(context-mode) :help
                     "Run ConTeXt until completion")
                    ("BibTeX" "bibtex %s" TeX-run-BibTeX nil t :help "Run 
BibTeX")
                    ("Biber" "biber %s" TeX-run-Biber nil t :help "Run Biber")
                    ("View" "%V" TeX-run-discard-or-function t t :help "Run 
Viewer")
                    ("Print" "%p" TeX-run-command t t :help "Print the file")
                    ("Queue" "%q" TeX-run-background nil t :help "View the 
printer queue"
                     :visible TeX-queue-command)
                    ("File" "%(o?)dvips %d -o %f " TeX-run-command t t :help
                     "Generate PostScript file")
                    ("Index" "makeindex %s" TeX-run-command nil t :help "Create 
index file")
                    ("Check" "lacheck %s" TeX-run-compile nil (latex-mode) :help
                     "Check LaTeX file for correctness")
                    ("Spell" "(TeX-ispell-document \"\")" TeX-run-function nil 
t :help
                     "Spell-check the document")
                    ("Clean" "TeX-clean" TeX-run-function nil t :help
                     "Delete generated intermediate files")
                    ("Clean All" "(TeX-clean t)" TeX-run-function nil t :help
                     "Delete generated intermediate and output files")
                    ("Other" "" TeX-run-command t t :help "Run an arbitrary 
command"))
 )
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