From: KOSAKI Motohiro <kosaki.motohiro@...>
Date: 2012-06-08T16:26:09+09:00
Subject: [ruby-core:45502] Re: [ruby-trunk - Feature #2715] Optimization to avoid spawning shell in Kernel#system call should check for failure conditions

On Fri, Jun 8, 2012 at 3:21 AM, akr (Akira Tanaka) <akr@fsij.org> wrote:
>
> Issue #2715 has been updated by akr (Akira Tanaka).
>
>
>> .... I realized IO.pid is crazy mistaken feature. It wouldn't work when using complex cmdline even if we will not remove the optimization. Sigh. (+_+
>
> Killing a complex command line, which invokes many processes, is a different problem.
> IO#pid is not a origin of the problem.
> spawn also have same problem as follows.
>
> �pid = spawn("foo & bar"); Process.kill(:TERM, pid)
>
> Do you say that returning pid feature of spawn is crazy mistaken?
>
> Killing a complex command line needs process group,
> as shell job control does.
>
> To return to this issue, I'm considering adding a new spawn option, :shell.
> This option disables the optimization.
>
> �system("simple command", :shell=>true)
>
> The default of the option is disabled as now.
>
> This option solves this issue as:
> - shell error messages are printed if :shell => true.
> - doesn't break programs which expects simple commands are direct child process.
> - don't need to implement mimic of shell error message printing feature in ruby.

Seems make sense.