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

From: Jeff King <peff@peff.net>
Date: Jan 19, 2021, 22:15 UTC
Message-ID: <YAdaAsP6vCQla/Ar@coredump.intra.peff.net>
In-Reply-To: <YAdWNgF75QEYFLA7@coredump.intra.peff.net>

On Tue, Jan 19, 2021 at 04:59:18PM -0500, Jeff King wrote:

Show 14 quoted lines

> > > What does "delimited by /" mean?
> > 
> > Ah, I just meant that it looks for the longest common prefix where it
> > will only split at '/' characters. But, that's not right at all:
> > find_longest_prefixes_1() will happily split anywhere there is a
> > difference.
> 
> Right. We thought in early revisions of the ref-filter work that we
> might have to split on path components, but it turns out that the
> underlying ref code is happy to take arbitrary prefixes. And it's that
> code which defines our strategy; Even if the ls-refs code wanted to
> allow only full path components, it should be using the limiting from
> for_each_ref_in() only as an optimization, and applying its own
> filtering to the output.

Having now looked carefully at the ls-refs code, it's a pure prefix-match, too. So I think we _could_ rely on for_each_fullref_in() returning us the correct full results, and not checking it further in send_ref(). But I kind of like keeping it there as an extra check (and one which could in theory grow more logic later).

-Peff