Re: git status: small difference between stating whole repository and small subdirectory

[Jeff King <peff@peff.net>]

On Mon, Feb 20, 2012 at 02:04:26PM -0800, Junio C Hamano wrote:

> > ... Things may have changed since then, of course, but I at
> > least know that they were sufficient in 34110cd^.
> 
> Looking at where cache_tree_free() is called, I think back then the
> two-way merge was deemed OK, but we did not trust three-way merge or
> merge-recursive at all.

Thanks, I'll take a look more closely at those cases.

> It is OK to check that we do not over-invalidate for performance, but it
> is a lot more important to make sure we do not under-invalidate for
> correctness.  I am a bit worried that you seem to be putting more stress
> on the former.

I think it is just selection bias of the specific parts of his tests
that I was responding to. I completely agree that correctness is way
more important, and I'm also trying to come up with tests to validate
correctness. I just wasn't talking about them there.

I still think replaying real-world test cases is going to be more likely
to find issues in invalidation. I can come up with lots of simple
test-cases, but they're not likely to find anything we wouldn't find in
the code with trivial inspection. I think a combination of careful
analysis and real-world validation is going to be more helpful in the
long run than the kind of simplistic tests that are in t0090.

-Peff