[PATCH v8 12/44] refs.c: ref_transaction_delete to check for error and return status

[Ronnie Sahlberg <sahlberg@google.com>]

Change ref_transaction_delete() to do basic error checking and return
non-zero of error. Update all callers to check the return for
ref_transaction_delete(). There are currently no conditions in _delete that
will return error but there will be in the future.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
---
 builtin/update-ref.c |  5 +++--
 refs.c               | 15 ++++++++++-----
 refs.h               | 11 +++++++----
 3 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 0924502..2a51df1 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -257,8 +257,9 @@ static const char *parse_cmd_delete(struct strbuf *input, const char *next)
 	if (*next != line_termination)
 		die("delete %s: extra input: %s", refname, next);
 
-	ref_transaction_delete(transaction, refname, old_sha1,
-			       update_flags, have_old);
+	if (ref_transaction_delete(transaction, refname, old_sha1,
+				   update_flags, have_old))
+		die("failed transaction delete for %s", refname);
 
 	update_flags = 0;
 	free(refname);
diff --git a/refs.c b/refs.c
index f38d3d6..6e5e940 100644
--- a/refs.c
+++ b/refs.c
@@ -3392,19 +3392,24 @@ int ref_transaction_create(struct ref_transaction *transaction,
 	return 0;
 }
 
-void ref_transaction_delete(struct ref_transaction *transaction,
-			    const char *refname,
-			    const unsigned char *old_sha1,
-			    int flags, int have_old)
+int ref_transaction_delete(struct ref_transaction *transaction,
+			   const char *refname,
+			   const unsigned char *old_sha1,
+			   int flags, int have_old)
 {
-	struct ref_update *update = add_update(transaction, refname);
+	struct ref_update *update;
 
+	if (have_old && !old_sha1)
+		die("BUG: have_old is true but old_sha1 is NULL");
+
+	update = add_update(transaction, refname);
 	update->flags = flags;
 	update->have_old = have_old;
 	if (have_old) {
 		assert(!is_null_sha1(old_sha1));
 		hashcpy(update->old_sha1, old_sha1);
 	}
+	return 0;
 }
 
 int update_ref(const char *action, const char *refname,
diff --git a/refs.h b/refs.h
index e3bdd57..cba2f3d 100644
--- a/refs.h
+++ b/refs.h
@@ -270,11 +270,14 @@ int ref_transaction_create(struct ref_transaction *transaction,
  * Add a reference deletion to transaction.  If have_old is true, then
  * old_sha1 holds the value that the reference should have had before
  * the update (which must not be the null SHA-1).
+ * Function returns 0 on success and non-zero on failure. A failure to delete
+ * means that the transaction as a whole has failed and will need to be
+ * rolled back.
  */
-void ref_transaction_delete(struct ref_transaction *transaction,
-			    const char *refname,
-			    const unsigned char *old_sha1,
-			    int flags, int have_old);
+int ref_transaction_delete(struct ref_transaction *transaction,
+			   const char *refname,
+			   const unsigned char *old_sha1,
+			   int flags, int have_old);
 
 /*
  * Commit all of the changes that have been queued in transaction, as
-- 
2.0.0.rc3.477.g0f8edf7