refs.c: make update_ref_write update a strbuf on failure

Change update_ref_write to also update an error strbuf on failure.
This makes the error available to ref_transaction_commit callers if the
transaction failed due to update_ref_sha1/write_ref_sha1 failures.

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>

diff --git a/refs.c b/refs.c
index 115f1431f781c89388e57ec3e88211e37d8cc3fa..003b313ade28dc5dc5cba4fb15edb504076124e3 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -3353,10 +3353,13 @@ static struct ref_lock *update_ref_lock(const char *refname,
 
 static int update_ref_write(const char *action, const char *refname,
                            const unsigned char *sha1, struct ref_lock *lock,
-                           enum action_on_err onerr)
+                           struct strbuf *err, enum action_on_err onerr)
 {
        if (write_ref_sha1(lock, sha1, action) < 0) {
                const char *str = "Cannot update the ref '%s'.";
+               if (err)
+                       strbuf_addf(err, str, refname);
+
                switch (onerr) {
                case UPDATE_REFS_MSG_ON_ERR: error(str, refname); break;
                case UPDATE_REFS_DIE_ON_ERR: die(str, refname); break;
@@ -3477,7 +3480,7 @@ int update_ref(const char *action, const char *refname,
        lock = update_ref_lock(refname, oldval, flags, NULL, onerr);
        if (!lock)
                return 1;
-       return update_ref_write(action, refname, sha1, lock, onerr);
+       return update_ref_write(action, refname, sha1, lock, NULL, onerr);
 }
 
 static int ref_update_compare(const void *r1, const void *r2)
@@ -3559,7 +3562,7 @@ int ref_transaction_commit(struct ref_transaction *transaction,
                        ret = update_ref_write(msg,
                                               update->refname,
                                               update->new_sha1,
-                                              update->lock, onerr);
+                                              update->lock, err, onerr);
                        update->lock = NULL; /* freed by update_ref_write */
                        if (ret)
                                goto cleanup;