Merge branch 'rs/ref-transaction-1'

The second batch of the transactional ref update series.

* rs/ref-transaction-1: (22 commits)
  update-ref --stdin: pass transaction around explicitly
  update-ref --stdin: narrow scope of err strbuf
  refs.c: make delete_ref use a transaction
  refs.c: make prune_ref use a transaction to delete the ref
  refs.c: remove lock_ref_sha1
  refs.c: remove the update_ref_write function
  refs.c: remove the update_ref_lock function
  refs.c: make lock_ref_sha1 static
  walker.c: use ref transaction for ref updates
  fast-import.c: use a ref transaction when dumping tags
  receive-pack.c: use a reference transaction for updating the refs
  refs.c: change update_ref to use a transaction
  branch.c: use ref transaction for all ref updates
  fast-import.c: change update_branch to use ref transactions
  sequencer.c: use ref transactions for all ref updates
  commit.c: use ref transactions for updates
  replace.c: use the ref transaction functions for updates
  tag.c: use ref transactions when doing updates
  refs.c: add transaction.status and track OPEN/CLOSED
  refs.c: make ref_transaction_begin take an err argument
  ...

1 files changed, 18 insertions, 8 deletions

diff --git a/sequencer.c b/sequencer.c
index 3c060e0547..5e8a207474 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -237,23 +237,33 @@ static int error_dirty_index(struct replay_opts *opts)
 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 			int unborn, struct replay_opts *opts)
 {
-	struct ref_lock *ref_lock;
+	struct ref_transaction *transaction;
 	struct strbuf sb = STRBUF_INIT;
-	int ret;
+	struct strbuf err = STRBUF_INIT;
 
 	read_cache();
 	if (checkout_fast_forward(from, to, 1))
 		exit(128); /* the callee should have complained already */
-	ref_lock = lock_any_ref_for_update("HEAD", unborn ? null_sha1 : from,
-					   0, NULL);
-	if (!ref_lock)
-		return error(_("Failed to lock HEAD during fast_forward_to"));
 
 	strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
-	ret = write_ref_sha1(ref_lock, to, sb.buf);
+
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, "HEAD",
+				   to, unborn ? null_sha1 : from,
+				   0, 1, &err) ||
+	    ref_transaction_commit(transaction, sb.buf, &err)) {
+		ref_transaction_free(transaction);
+		error("%s", err.buf);
+		strbuf_release(&sb);
+		strbuf_release(&err);
+		return -1;
+	}
 
 	strbuf_release(&sb);
-	return ret;
+	strbuf_release(&err);
+	ref_transaction_free(transaction);
+	return 0;
 }
 
 static int do_recursive_merge(struct commit *base, struct commit *next,