refs: add create_only option to refs_update_symref_extended

Allow the caller to specify that it only wants to update the symref if
it does not already exist. Silently ignore the error from the
transaction API if the symref already exists.

Signed-off-by: Bence Ferdinandy <bence@ferdinandy.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/remote.c b/builtin/remote.c
index 6d659d6..3dc1135 100644 (file)
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -1476,7 +1476,7 @@ static int set_head(int argc, const char **argv, const char *prefix)
                goto cleanup;
        }
        was_detached = refs_update_symref_extended(refs, b_head.buf, b_remote_head.buf,
-                       "remote set-head", &b_local_head);
+                       "remote set-head", &b_local_head, 0);
        if (was_detached == -1) {
                result |= error(_("Could not set up %s"), b_head.buf);
                goto cleanup;

diff --git a/refs.c b/refs.c
index d80efd5..2efa6bc 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -2116,26 +2116,38 @@ int peel_iterated_oid(struct repository *r, const struct object_id *base, struct
 int refs_update_symref(struct ref_store *refs, const char *ref,
                       const char *target, const char *logmsg)
 {
-       return refs_update_symref_extended(refs, ref, target, logmsg, NULL);
+       return refs_update_symref_extended(refs, ref, target, logmsg, NULL, 0);
 }
 
 int refs_update_symref_extended(struct ref_store *refs, const char *ref,
                       const char *target, const char *logmsg,
-                      struct strbuf *referent)
+                      struct strbuf *referent, int create_only)
 {
        struct ref_transaction *transaction;
        struct strbuf err = STRBUF_INIT;
-       int ret = 0;
+       int ret = 0, prepret = 0;
 
        transaction = ref_store_transaction_begin(refs, &err);
-       if (!transaction ||
-           ref_transaction_update(transaction, ref, NULL, NULL,
-                                  target, NULL, REF_NO_DEREF,
-                                  logmsg, &err) ||
-           ref_transaction_prepare(transaction, &err)) {
+       if (!transaction) {
+       error_return:
                ret = error("%s", err.buf);
                goto cleanup;
        }
+       if (create_only) {
+               if (ref_transaction_create(transaction, ref, NULL, target,
+                                          REF_NO_DEREF, logmsg, &err))
+                       goto error_return;
+               prepret = ref_transaction_prepare(transaction, &err);
+               if (prepret && prepret != TRANSACTION_CREATE_EXISTS)
+                       goto error_return;
+       } else {
+               if (ref_transaction_update(transaction, ref, NULL, NULL,
+                                          target, NULL, REF_NO_DEREF,
+                                          logmsg, &err) ||
+                       ref_transaction_prepare(transaction, &err))
+                       goto error_return;
+       }
+
        if (referent && refs_read_symbolic_ref(refs, ref, referent) == NOT_A_SYMREF) {
                struct object_id oid;
                if (!refs_read_ref(refs, ref, &oid)) {
@@ -2144,8 +2156,11 @@ int refs_update_symref_extended(struct ref_store *refs, const char *ref,
                }
        }
 
+       if (prepret == TRANSACTION_CREATE_EXISTS)
+               goto cleanup;
+
        if (ref_transaction_commit(transaction, &err))
-               ret = error("%s", err.buf);
+               goto error_return;
 
 cleanup:
        strbuf_release(&err);

diff --git a/refs.h b/refs.h
index b243739..be38377 100644 (file)
--- a/refs.h
+++ b/refs.h
@@ -586,7 +586,7 @@ int refs_update_symref(struct ref_store *refs, const char *refname,
 
 int refs_update_symref_extended(struct ref_store *refs, const char *refname,
                       const char *target, const char *logmsg,
-                      struct strbuf *referent);
+                      struct strbuf *referent, int create_only);
 
 enum action_on_err {
        UPDATE_REFS_MSG_ON_ERR,