Re: [PATCH 0/4] perf improvements for git-describe with few tags

From: Jeff King <peff@peff.net>
Date: Dec 4, 2024, 23:20 UTC
Message-ID: <20241204232016.GA1460459@coredump.intra.peff.net>
In-Reply-To: <fxbv4ihz4sgdfwtq4vkadntank2lzwkt6abgipuojhumjmuxjs@fegutv3kcamo>

On Wed, Dec 04, 2024 at 03:04:59PM -0800, Josh Steadmon wrote:

> This breaks the case of `git describe --always $SOME_HASH` (we hit the
> die at builtin/describe.c:340) when there are no tags in the repo. I can
> send a test case and a small fix shortly.

Yeah, this is easy to reproduce. I think it was always broken with:

  git describe --candidates=0 --always ...

since there is a line that skips the whole algorithm and bails early if there are no candidates allowed. But that should surely not kick in if "always" is set. I.e., I'd expect the fix to be something like:

diff --git a/builtin/describe.c b/builtin/describe.c
index d6c77a714f..d4c869e3d5 100644
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -332,7 +332,7 @@ static void describe_commit(struct object_id *oid, struct strbuf *dst)
 		return;
 	}
 
-	if (!max_candidates)
+	if (!max_candidates && !always)
 		die(_("no tag exactly matches '%s'"), oid_to_hex(&cmit->object.oid));
 	if (debug)
 		fprintf(stderr, _("No exact match on refs or tags, searching to describe\n"));

But I'll wait and see what your proposed fix looks like.

-Peff