t: allow skipping expected object ID in `ref-store update-ref`

We require the caller to pass both the old and new expected object ID to
our `test-tool ref-store update-ref` helper. When trying to update a
symbolic reference though it's impossible to specify the expected object
ID, which means that the test would instead have to force-update the
reference. This is currently impossible though.

Update the helper to optionally skip verification of the old object ID
in case the test passes in an empty old object ID as input.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/helper/test-ref-store.c b/t/helper/test-ref-store.c
index 48552e6a9e0049365185499c02d9b1c7d1069d0c..702ec1f128ad42443bc093614dee971c7106af77 100644 (file)
--- a/t/helper/test-ref-store.c
+++ b/t/helper/test-ref-store.c
@@ -298,16 +298,19 @@ static int cmd_update_ref(struct ref_store *refs, const char **argv)
        const char *new_sha1_buf = notnull(*argv++, "new-sha1");
        const char *old_sha1_buf = notnull(*argv++, "old-sha1");
        unsigned int flags = arg_flags(*argv++, "flags", transaction_flags);
-       struct object_id old_oid;
+       struct object_id old_oid, *old_oid_ptr = NULL;
        struct object_id new_oid;
 
-       if (get_oid_hex(old_sha1_buf, &old_oid))
-               die("cannot parse %s as %s", old_sha1_buf, the_hash_algo->name);
+       if (*old_sha1_buf) {
+               if (get_oid_hex(old_sha1_buf, &old_oid))
+                       die("cannot parse %s as %s", old_sha1_buf, the_hash_algo->name);
+               old_oid_ptr = &old_oid;
+       }
        if (get_oid_hex(new_sha1_buf, &new_oid))
                die("cannot parse %s as %s", new_sha1_buf, the_hash_algo->name);
 
        return refs_update_ref(refs, msg, refname,
-                              &new_oid, &old_oid,
+                              &new_oid, old_oid_ptr,
                               flags, UPDATE_REFS_DIE_ON_ERR);
 }