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From: Jeff King <>
Cc: Patrick Steinhardt <>
Subject: [PATCH 7/8] refs: check refnames as fully qualified when writing
Date: Mon, 29 Apr 2024 04:34:01 -0400	[thread overview]
Message-ID: <> (raw)

When a ref update is queued via ref_transaction_update(), we call
check_refname_format() to make sure the name is acceptable. We pass
REFNAME_ALLOW_ONELEVEL, which allows pseudorefs like MERGE_HEAD. But
that's not enough to forbid names outside of refs/ like "foo/bar" or
even scary stuff like "config" (though fortunately I think that should
never work because we cannot resolve "config" to read the old value).

Let's instead pass REFNAME_FULLY_QUALIFIED, which tells the checking
function that we really do have a full refname, and it can enforce
it as such.

This means that "git update-ref foo/bar HEAD" will now be rejected. Note
that _deleting_ such a ref is already forbidden (and there is a test in
t1430 for that already), due to some confusing differences between
check_refname_format() and refname_is_safe(). See the previous commit
for more details.

Signed-off-by: Jeff King <>
 refs.c                  |  2 +-
 t/ | 10 ++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/refs.c b/refs.c
index 44b4419050..57663cfe9e 100644
--- a/refs.c
+++ b/refs.c
@@ -1267,7 +1267,7 @@ int ref_transaction_update(struct ref_transaction *transaction,
 	    ((new_oid && !is_null_oid(new_oid)) ?
-		     check_refname_format(refname, REFNAME_ALLOW_ONELEVEL) :
+		     check_refname_format(refname, REFNAME_FULLY_QUALIFIED) :
 			   !refname_is_safe(refname))) {
 		strbuf_addf(err, _("refusing to update ref with bad name '%s'"),
diff --git a/t/ b/t/
index 0c00118c2b..120e1557d7 100755
--- a/t/
+++ b/t/
@@ -390,4 +390,14 @@ test_expect_success 'branch -m can rename refs/heads/-dash' '
 	git show-ref refs/heads/dash
+test_expect_success 'update-ref refuses lowercase outside of refs/' '
+	test_must_fail git update-ref lowercase HEAD 2>err &&
+	test_grep "refusing to update ref with bad name" err
+test_expect_success 'update-ref refuses non-underscore outside of refs/' '
+	test_must_fail git update-ref FOO/HEAD HEAD 2>err &&
+	test_grep "refusing to update ref with bad name" err

                 reply	other threads:[~2024-04-29  8:34 UTC|newest]

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