From: Jeff King <peff@peff.net>
Date: Fri, 28 Aug 2015 18:44:05 GMT
Subject: Re: [PATCH 7/9] fetch: fetch submodules in parallel
Message-ID: <20150828184405.GA17721@sigill.intra.peff.net>
In-Reply-To: <CAGZ79kZALSJ9oY+6ZwyQ9CPFiV-AAq7c-r9mxw3N+gvsDw8m4A@mail.gmail.com>

On Fri, Aug 28, 2015 at 11:41:17AM -0700, Stefan Beller wrote:

> > So to an observer, it would look like a serial operation, but subsequent
> > operations after the first would magically go much faster (because
> > they'd been working and buffering in the background).
> >
> > And that doesn't require any additional IPC magic (though I am not sure
> > how we get progress in the first place if the child stderr is a
> > pipe...).
> 
> Moving the contents from the pipe to a strbuf buffer which we can grow
> indefinitely
> (way larger than pipe limits, but the output of a git fetch should be
> small enough for that).

Right, clearly we can't rely on pipe buffers to be large enough here
(though we _may_ want to rely on tempfiles if we aren't sure that the
stdout is bounded in a reasonable way).

But what I meant was: the child will only show progress if stderr is a
tty, but here it is not.

I wonder if we need to set GIT_STDERR_IS_TTY=1 in the parent process,
and then respect it in the children (this is similar to what
GIT_PAGER_IN_USE does for stdout).

-Peff