Re: t5401-update-hooks test failure

From: Shawn O. Pearce <spearce@spearce.org>
Date: Feb 9, 2010, 19:26 UTC
Message-ID: <20100209192628.GC28936@spearce.org>
In-Reply-To: <alpine.LFD.2.00.1002091337421.1681@xanadu.home>

Nicolas Pitre <nico@fluxnic.net> wrote:

Show 12 quoted lines

> On Tue, 9 Feb 2010, Shawn O. Pearce wrote:
> > 
> > builtin-send-pack.c clearly isn't stopping early while processing
> > the stream, since we see later messages from the post-receive and
> > post-update hooks just fine.
> > 
> > So I think the only code that is in question is the case 2 arm of
> > recv_sideband().  But to be honest, I can't find any fault with it.
> 
> Note that strict order of messages passed through the sideband can't be 
> relied upon.  Often you have sideband 1 connected to stdin and sideband 
> 2 connected to stderr,

Oh.  Sure.  But that isn't really the case here.

The messages are all coming down side band #2, before we write anything down side band #1. The missing message in question should have appeared somewhere in the middle of that side band #2 stream that we are seeing in the test output. Given that its all serialized down into a single stream by the parent process receive-pack, we really shouldn't see the messages out of order.

> and they are linked with pipes, and various 
> factors such as stdio buffering or even printf implementation in the C 
> lib

The only way I can see this missing message happening is if the C library isn't flushing the stdio buffer before the hook process exits. Given that the hook process is a /bin/sh shell script, and its using echo to print its messages... I'm at a loss for how to fix that in Git.

Unless its the recv_sideband() somehow skipping a line. But I can't see it doing that.

-- 
Shawn.