bug#8265: 24.0.50; windows emacs hanging calling svn

[Sam Steingold <sds@gnu.org>]

In GNU Emacs 24.0.50.1 (i386-mingw-nt5.2.3790)
 of 2011-03-16 on SDS
Windowing system distributor `Microsoft Corp.', version 5.2.3790
configured using `configure --with-gcc (3.4) --cflags -IC:/gnu/gnuwin32/include --ldflags -LC:/gnu/gnuwin32/lib'

When I modify a file which is under svn, emacs _often_ (but not always!)
hangs calling svn to update its vc status and hangs even though svn
seems to work just fine.

I either have to kill svn using the windows task manager (in which case
I get this error:

Debugger entered--Lisp error: (error "Running svn status -v foo.cpp...FAILED (status 1)")
  signal(error ("Running svn status -v foo.cpp...FAILED (status 1)"))
  error("Running %s...FAILED (%s)" "svn status -v foo.cpp" "status 1")
  vc-do-command(t 0 "svn" "d:/dir/foo.cpp" "status" "-v")
  apply(vc-do-command t 0 "svn" "d:/dir/foo.cpp" ("status" "-v"))
  vc-svn-command(t 0 "d:/dir/foo.cpp" "status" "-v")
  vc-svn-state("d:/dir/foo.cpp" local)
  vc-svn-state-heuristic("d:/dir/foo.cpp")
  apply(vc-svn-state-heuristic "d:/dir/foo.cpp")
  vc-call-backend(SVN state-heuristic "d:/dir/foo.cpp")
  vc-state-refresh("d:/dir/foo.cpp" SVN)
  vc-after-save()
  basic-save-buffer()
  save-buffer(1)
  call-interactively(save-buffer nil nil)

)

Or I have to hit C-g in which case I have to wait for a long time, and
then the mouse cursor jumps to a different emacs frame(!) and a message
appears "waiting for process to die...(type C-g again to kill it instantly)"
and then I hit C-g again (several times!) and wait some more and then
finally emacs starts responding and a windows "End Program" dialog box
appears asking me whether I indeed want to kill "svn.exe".
Then I need to do C-/ (undo) in the buffer into which Emacs moved my
cursor because a bunch of "g" characters were inserted there.

Basically, it is very frustrating: half my buffer saves are accompanies
by this game of killing svn.exe.

Note that this is native windows mingw emacs build + cygwin svn.exe.
I do have a native svn.exe which exhibits the exact same behavior, but,
additionally, cannot talk to cygwin ssh-agent so it requires me to enter
my password for every operation.

-- 
Sam Steingold (http://sds.podval.org/) on CentOS release 5.5 (Final) X
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