set process-connection-type to nil, to fix issue with gvfs-open

[egh]

This fixes the issues described here:

• https://bugzilla.gnome.org/show_bug.cgi?id=652262
• https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=741651

and should have no effect on other programs.

[jech]

Could you please explain how using a pipe instead of a pty works around the issue of gvfs-open exiting too early?

[egh]

Hi Juliusz,

Thanks for looking into this. The problem is described in comment #15 here (https://bugzilla.gnome.org/show_bug.cgi?id=652262#c15):

There is a related problem also caused by gvfs-open exiting too early: if gvfs-open is run under a new pty, then it is the session group leader, and when it exits, its children are killed. There's a race condition: sometimes they can have had time to detach themselves (I've seen this happen when running gvfs-open under ltrace); other times, gvfs-open completes successfully, but the child is killed. The fix is to have gvfs-open call setsid() to put it in its own process group.

The emacs lisp manual also suggests that using process-connection-type nil is better in this case:

For subprocesses used for internal purposes by programs, it is often better to use a pipe, because they are more efficient, and because they are immune to stray character injections that ptys introduce for large (around 500 byte) messages. Also, the total number of ptys is limited on many systems and it is good not to waste them.

[ikazuhiro]

Merged at https://github.com/wanderlust/semi/commit/8045d8b052ec043b6d16f9840d28cc5333c27e27, but not tested.

[egh]

Thank you!