From: Jeff King <peff@peff.net>
Date: Fri, 13 May 2016 20:02:33 GMT
Subject: Re: t3404 static check of bad SHA-1 failure
Message-ID: <20160513200232.GA10371@sigill.intra.peff.net>
In-Reply-To: <20160513195911.GE9890@sigill.intra.peff.net>

On Fri, May 13, 2016 at 03:59:11PM -0400, Jeff King wrote:

> On Fri, May 13, 2016 at 12:52:44PM -0700, Junio C Hamano wrote:
> 
> > I _think_ "test -z" should succeed according to POSIX, because
> > 
> >  (1) it is not "test -z string" because it lacks string,
> > 
> >  (2) it is not any of the other "test -<option> thing" because -z,
> >     and
> > 
> >  (3) the only thing it matches in the supported form of "test" is
> >      "test <string>" that tests if the <string> is not the null
> >      string, and "-z" indeed is not the null string.
> > 
> > For the same reason, "test -n" succeeds.
> 
> Yeah, I think you're right; POSIX is pretty clear that this falls under
> case 3. So that means "test -z" quietly does what we want. But it means
> that "test -n" does the _opposite_ of what we want.
> 
> And sadly,
> 
>   git grep 'test -n [^"]'
> 
> is not empty.
> 
> > But working around older/broken shells is easy and the resulting
> > script it more readable, so let's take this.  It makes the resulting
> > code easier to understand even when we know we run it under POSIX
> > shell.
> 
> Yep. The POSIX-explanation of what is going on might be worth putting in
> the commit message for the "-z" case (i.e., it should work, but the
> "why" is subtle).

I think we can just lump all of these into a single patch, but there are
a few related cleanups, including the SVN stuff I just sent. So let me
send out a unified patch series in a moment.

-Peff