Subject: [PATCH v7 6/8] refs: use transaction in `refs_create_symref()`

From: Karthik Nayak <[email-masked]>
Date: Tue, 7 May 2024 08:00:33 +0200

From: Karthik Nayak <[email-masked]>

The `refs_create_symref()` function updates a symref to a given new
target. To do this, it uses a ref-backend specific function
`create_symref()`.

In the previous commits, we introduced symref support in transactions.
This means we can now use transactions to perform symref updates and
don't have to resort to `create_symref()`. Doing this allows us to
remove and cleanup `create_symref()`, which we will do in the following
commit.

Modify the expected error message for a test in
't/t0610-reftable-basics.sh', since the error is now thrown from
'refs.c'. This is because in transactional updates, F/D conflicts are
caught before we're in the reference backend.

Signed-off-by: Karthik Nayak <[email-masked]>
---
 refs.c                           | 24 +++++++++++++++++-------
 t/t1416-ref-transaction-hooks.sh | 23 +++++++++++++++++++++++
 2 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/refs.c b/refs.c
index f3d6b3b8e3..7a693dbcfb 100644
--- a/refs.c
+++ b/refs.c
@@ -2305,14 +2305,24 @@ int refs_create_symref(struct ref_store *refs,
 		       const char *refs_heads_master,
 		       const char *logmsg)
 {
-	char *msg;
-	int retval;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
+	int ret = 0;
 
-	msg = normalize_reflog_message(logmsg);
-	retval = refs->be->create_symref(refs, ref_target, refs_heads_master,
-					 msg);
-	free(msg);
-	return retval;
+	transaction = ref_store_transaction_begin(refs, &err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, ref_target, NULL, NULL,
+				   refs_heads_master, NULL, REF_NO_DEREF,
+				   logmsg, &err) ||
+	    ref_transaction_commit(transaction, &err)) {
+		ret = error("%s", err.buf);
+	}
+
+	strbuf_release(&err);
+	if (transaction)
+		ref_transaction_free(transaction);
+
+	return ret;
 }
 
 int create_symref(const char *ref_target, const char *refs_heads_master,
diff --git a/t/t1416-ref-transaction-hooks.sh b/t/t1416-ref-transaction-hooks.sh
index 2092488090..067fd57290 100755
--- a/t/t1416-ref-transaction-hooks.sh
+++ b/t/t1416-ref-transaction-hooks.sh
@@ -134,4 +134,27 @@ test_expect_success 'interleaving hook calls succeed' '
 	test_cmp expect target-repo.git/actual
 '
 
+test_expect_success 'hook captures git-symbolic-ref updates' '
+	test_when_finished "rm actual" &&
+
+	test_hook reference-transaction <<-\EOF &&
+		echo "$*" >>actual
+		while read -r line
+		do
+			printf "%s\n" "$line"
+		done >>actual
+	EOF
+
+	git symbolic-ref refs/heads/symref refs/heads/main &&
+
+	cat >expect <<-EOF &&
+	prepared
+	$ZERO_OID ref:refs/heads/main refs/heads/symref
+	committed
+	$ZERO_OID ref:refs/heads/main refs/heads/symref
+	EOF
+
+	test_cmp expect actual
+'
+
 test_done
-- 
2.43.GIT