[PATCH v17 15/48] refs.c: make ref_update_reject_duplicates take a strbuf argument for errors

[Ronnie Sahlberg <sahlberg@google.com>]

Make ref_update_reject_duplicates return any error that occurs through a
new strbuf argument. This means that when a transaction commit fails in
this function we will now be able to pass a helpful error message back to the
caller.

Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
---
 refs.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/refs.c b/refs.c
index 31ae63e..81d3605 100644
--- a/refs.c
+++ b/refs.c
@@ -3463,6 +3463,7 @@ static int ref_update_compare(const void *r1, const void *r2)
 }
 
 static int ref_update_reject_duplicates(struct ref_update **updates, int n,
+					struct strbuf *err,
 					enum action_on_err onerr)
 {
 	int i;
@@ -3470,6 +3471,9 @@ static int ref_update_reject_duplicates(struct ref_update **updates, int n,
 		if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
 			const char *str =
 				"Multiple updates for ref '%s' not allowed.";
+			if (err)
+				strbuf_addf(err, str, updates[i]->refname);
+
 			switch (onerr) {
 			case UPDATE_REFS_MSG_ON_ERR:
 				error(str, updates[i]->refname); break;
@@ -3500,7 +3504,7 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 
 	/* Copy, sort, and reject duplicate refs */
 	qsort(updates, n, sizeof(*updates), ref_update_compare);
-	ret = ref_update_reject_duplicates(updates, n, onerr);
+	ret = ref_update_reject_duplicates(updates, n, err, onerr);
 	if (ret)
 		goto cleanup;
 
-- 
2.0.0.282.g3799eda.dirty