Re: [PATCH v6 2/7] cherry-pick: treat CHERRY_PICK_HEAD and REVERT_HEAD as refs

Instead of directly writing to and reading from files in
$GIT_DIR, use ref API to interact with CHERRY_PICK_HEAD
and REVERT_HEAD.

Signed-off-by: David Turner <redacted>
---
 branch.c                         |  4 ++--
 builtin/commit.c                 |  6 +++---
 builtin/merge.c                  |  2 +-
 contrib/completion/git-prompt.sh |  4 ++--
 git-gui/lib/commit.tcl           |  2 +-
 sequencer.c                      | 39 ++++++++++++++++++++-------------------
 t/t7509-commit.sh                |  4 ++--
 wt-status.c                      |  6 ++----
 8 files changed, 33 insertions(+), 34 deletions(-)

[...]

diff --git a/sequencer.c b/sequencer.c
index f8421a8..44c43e5 100644
--- a/sequencer.c
+++ b/sequencer.c

@@ -158,21 +158,22 @@ static void free_message(struct commit *commit, struct commit_message *msg)
 	unuse_commit_buffer(commit, msg->message);
 }
 
-static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
+static void write_cherry_pick_head(struct commit *commit, const char *ref)
 {
-	const char *filename;
-	int fd;
-	struct strbuf buf = STRBUF_INIT;
+	struct strbuf err = STRBUF_INIT;
+	void *transaction;
 
-	strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
+	transaction = ref_transaction_begin(&err);
+	if (!transaction)
+		die(_("Could not create transaction: %s"), err.buf);
 
-	filename = git_path("%s", pseudoref);
-	fd = open(filename, O_WRONLY | O_CREAT, 0666);
-	if (fd < 0)
-		die_errno(_("Could not open '%s' for writing"), filename);
-	if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
-		die_errno(_("Could not write to '%s'"), filename);
-	strbuf_release(&buf);
+	if (ref_transaction_update(transaction, ref, commit->object.sha1,
+				   NULL, REF_NODEREF, NULL,
+				   &err))
+		die(_("Could not write ref %s: %s"), ref, err.buf);
+
+	if (ref_transaction_commit(transaction, &err))
+		die(_("Could not commit ref write %s: %s"), ref, err.buf);
 }

 static void print_advice(int show_hint, struct replay_opts *opts)

@@ -186,7 +187,7 @@ static void print_advice(int show_hint, struct replay_opts *opts)

[...]