Subject: Re: The transfer.hideRefs of the upload-pack process does not work properly

From: Patrick Steinhardt <[email-masked]>
Date: Tue, 4 Mar 2025 12:38:50 +0100

On Tue, Mar 04, 2025 at 02:51:46AM -0500, Jeff King wrote:
> On Tue, Mar 04, 2025 at 02:51:14AM -0500, Jeff King wrote:
> 
> > From your reproduction, it looks like the issue is that for loose refs,
> > asking for_each_ref() to exclude "refs/heads/foo" will not yield
> > "refs/heads/foo/bar", but will yield "refs/heads/foo-bar".
> > 
> > And that was true for packed-refs, too, before 59c35fac54
> > (refs/packed-backend.c: implement jump lists to avoid excluded
> > pattern(s), 2023-07-10). After that, packed-refs exclude both.
> 
> Oh, and of course it would be interesting to know how reftables behave
> here, too, as I think they recently learned about exclusions.

Well, we have tests that explicitly verify that prefixes cause us to
exclude such refs in t1419, "overlapping exclude regions". So the
reftable backend is bug-compatible :)

Guess we'll need something similar to the following:

diff --git a/refs/reftable-backend.c b/refs/reftable-backend.c
index 7e90e13f745..45462f2ce6d 100644
--- a/refs/reftable-backend.c
+++ b/refs/reftable-backend.c
@@ -594,6 +594,16 @@ static int should_exclude_current_ref(struct reftable_ref_iterator *iter)
 		if (cmp < 0)
 			return 0;
 
+		/*
+		 * The exclude pattern needs to either match exactly, or, if it
+		 * is a prefix of the given reference, it must be a containing
+		 * directory.
+		 */
+		if (iter->ref.refname[iter->exclude_patterns_strlen] &&
+		    pattern[iter->exclude_patterns_strlen - 1] != '/' &&
+		    iter->ref.refname[iter->exclude_patterns_strlen] != '/')
+			return 0;
+
 		/*
 		 * The reference shares a prefix with the exclude pattern and
 		 * shall thus be omitted. We skip all references that match the

Patrick