Re: (call-process ...) hangs in emacs

[Katsumi Yamaoka <yamaoka@jpl.org>]

On Thu, 31 Jul 2014 15:51:49 +0100, Peter Hull wrote:
> VC integration in emacs has stopped working for me in the past few
> days. Using emacs debugger I found the last function call was to
> call-process which never returns.

> I can reproduce this by evaluating in Lisp Interaction mode (using ^J)
> (call-process "pwd" nil t)
> I would expect to see the PWD and exit code but instead it just hangs
> until I Quit it (^G)

> I am using GNU Emacs 24.3.1 and confirmed cygwin and all packages up
> to date. (cygwin DLL 1.7.31)

I'm troubled with a similar problem since Wednesday[1].
/usr/bin/emacs that Cygwin distributed (24.3) seems ok, but
/usr/local/bin/emacs that I built from the Emacs trunk Tuesday
(24.4.50) got not to work conditionally.  With that version of
Emacs:

Evaluating the form `(call-process "pwd" nil t)' on normally
running Emacs works.  It returns "/home/yamaoka" immediately.
However, if it is done in the bacth mode,

/usr/local/bin/emacs -Q -batch -eval '(call-process "pwd" nil t)'

it never returns; the Emacs process eats no cpu but stays
consistently[2].  `kill -9 PID' has no effect.
Using the Windows Task Manager is the only means to kill it.

I tried to rebuild that version of Emacs from scratch, but failed.
During bootstrap, bootstrap-emacs for the first use never returns
as follows (a trigger that makes bootstrap-emacs hang might be
different, though):

make[3]: Entering directory '/Work/emacs/lisp'
EMACSLOADPATH= '../src/bootstrap-emacs.exe' -batch --no-site-file --no-site-lisp -l autoload \
   --eval "(setq generate-autoload-cookie \";;;###cal-autoload\")" \
   --eval "(setq generated-autoload-file (expand-file-name (unmsys--file-name \"calendar/cal-loaddefs.el\")))" \
   -f batch-update-autoloads ./calendar
Wrote /Work/emacs/lisp/calendar/cal-loaddefs.el

(Note: the cal-loaddefs.el file is created but bootstrap-emacs
 doesn't exit.)

Thanks.

[1] I did updating my Cygwin installation on Wednesday morning
 for the first time in the last 7 days.  It must be the trigger
 of the problem.  I also tried clean install of Cygwin, however
 it didn't help.  Since it didn't seem to finish because of
 texlive-collection-basic.sh (the bash process didn't eat cpu,
 but never returned), I redid it by marking all the texlive
 packages to be `Skip'.

[2] The configure script of some packages uses `call-process' in
 the batch mode of Emacs in order to examine something.  It
 prevents the package from being built because of this problem.

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple