Re: [PATCH 0/4] Re: [PATCH 3/4] t: rev-parse-parents: avoid yoda conditions

From: Jeff King <peff@peff.net>
Date: Sep 4, 2013, 18:36 UTC
Message-ID: <20130904183559.GA3465@sigill.intra.peff.net>
In-Reply-To: <xmqq1u54o5c4.fsf@gitster.dls.corp.google.com>

On Wed, Sep 04, 2013 at 10:38:03AM -0700, Junio C Hamano wrote:

Show 12 quoted lines

> >> This is way off tangent, but I am somewhat sympathetic to Felipe's
> >> "compare actual with expect", with reservations.
> >
> > This isn't an argument either way, but note that JUnit (and NUnit and
> > PHPUnit) all have assertEquals methods that take the arguments in the
> > order "expect, actual".  I've always assumed that Git's test framework
> > was imitating that,...
> 
> No.  See 82ebb0b6 (add test_cmp function for test scripts,
> 2008-03-12).  The "test_cmp" was a replacement for "diff -u", and
> the same order we fed "diff -u", i.e. expect then actual, was
> carried over.

I don't think it was intentional at the time. But over the intervening 5 years, I have noticed that I certainly think of "test_cmp A B" as "differences from A to B", and the order makes sense. IOW, the "test_cmp is diff" abstraction is leaky, and that is fine (if it were not leaky, then order would not matter at all, but it clearly does).

But let's take a step back. This seems like an endian-ness issue to me. I.e., some people prefer one order for test assertions, and other people prefer the other. Is anyone actually right, or is this simply a matter of preference? And if it is simply a matter of preference, then why bother going through the pain of changing the current project standard?

Though I prefer the current, I can certainly live and adapt to a changed standard, and I do not mind doing so if there is a good reason. But I've yet to see any argument beyond "it is not what I like". Which to me argues for the status quo as the path of least resistance.

-Peff