Re: master 2c79a8f 2/2: Use posix_spawn if possible.

[Eli Zaretskii]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Thu, 31 Dec 2020 21:24:50 +0100
> Cc: Emacs developers <emacs-devel@gnu.org>
> 
> > > Most processes don't need a TTY. Only those that interact with the
> > > user (shell, term, interactive compile, ...) do, but that's probably a
> > > minority.
> >
> > I'm not sure it's a minority.  How about if you come up with a list of
> > specific commands that launch subprocesses which don't need a PTY?
> 
> Such a list would be difficult to compile because the connection type
> often depends on ambient state (the value of process-connection-type).
> What I've done instead is
> (1) counting the connection types in my current interactive session
> doing "typical" work
> (2) counting them in the Emacs unit test suite.
> I don't know how representative that is, but in both cases pipe
> processes significantly outnumbered pty processes (296 vs. 10 for (1)
> and 831 vs. 122 for (2)).

That's strange, because every important feature using subprocesses
that I frequently invoke seems to want PTY: gdb, ispell,
flyspell-mode, compile, grep, man, shell...

> > But assuming you are right, you intend to audit all the places where
> > we start a process and switch their :connection-type to nil if needed?
> 
> It's not needed (the default works fine in typical cases), the TTY
> setup is just superfluous in many cases.

But then we won't be able to benefit from posix_spawn, right?