Re: [PATCH 1/1] ls-refs.c: minimize number of refs visited

On Tue, Jan 19, 2021 at 05:53:56PM -0500, Jeff King wrote:

Thanks for posting this. I have a vague recollection that we considered
this either when we did the for-each-ref prefixes, or when we added
ls-refs prefixes, but I can't seem to find either. At any rate, at
GitHub we haven't generally found it to be a problem because our
horrifically-large repos tend to be aggregated alternates repos, not the
ones people serve upload-pack out of (though I did just time it, and
some of our largest repos should save a few hundred milliseconds per
advertisement, which is certainly not nothing).

Great on all counts!

quoted

This commit also fixes a bug in ls-refs.c that was not triggered
before: we were using a strvec set to zero, which is not how you are
supposed to initialize a strvec. We now call strvec_init after zeroing.

Good catch. It didn't matter until now because nobody relied on having a
NULL entry when no prefix had been added (instead, they always iterated
over prefixes->nr). IMHO that is worth fixing as a separate commit.

Yeah. Even after calling it out as such myself, I promptly forgot it
when preparing the first patch I sent back to Jacob!

I didn't pull it out into its own patch, and rather folded it in to my
2/2. It has a small call-out of its own, but if you'd prefer it by
itself, I'm happy to resubmit it with that change included.

-Peff

Thanks,
Taylor