refs.c: add a strbuf argument to ref_transaction_commit for error logging

Add a strbuf argument to _commit so that we can pass an error string back to
the caller. So that we can do error logging from the caller instead of from
_commit.

Longer term plan is to first convert all callers to use onerr==QUIET_ON_ERR
and craft any log messages from the callers themselves and finally remove the
onerr argument completely.

Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Acked-by: Michael Haggerty <mhagger@alum.mit.edu>

1 files changed, 4 insertions, 1 deletions

diff --git a/refs.h b/refs.h
index 8c7f9c4..09d3564 100644
--- a/refs.h
+++ b/refs.h
@@ -269,9 +269,12 @@ void ref_transaction_delete(struct ref_transaction *transaction,
  * Commit all of the changes that have been queued in transaction, as
  * atomically as possible.  Return a nonzero value if there is a
  * problem.
+ * If err is non-NULL we will add an error string to it to explain why
+ * the transaction failed. The string does not end in newline.
  */
 int ref_transaction_commit(struct ref_transaction *transaction,
-			   const char *msg, enum action_on_err onerr);
+			   const char *msg, struct strbuf *err,
+			   enum action_on_err onerr);
 
 /*
  * Free an existing transaction and all associated data.