Function is_dup_ref

refs/ref-cache.c:202–218

* Emit a warning and return true iff ref1 and ref2 have the same name * and the same oid. Die if they have the same name but different * oids. */

 * oids.
 */
static int is_dup_ref(const struct ref_entry *ref1, const struct ref_entry *ref2)
{
	if (strcmp(ref1->name, ref2->name))
		return 0;

	/* Duplicate name; make sure that they don't conflict: */

	if ((ref1->flag & REF_DIR) || (ref2->flag & REF_DIR))
		/* This is impossible by construction */
		die("Reference directory conflict: %s", ref1->name);

	if (!oideq(&ref1->u.value.oid, &ref2->u.value.oid))
		die("Duplicated ref, and SHA1s don't match: %s", ref1->name);

	warning("Duplicated ref: %s", ref1->name);
	return 1;
}

/*
 * Sort the entries in dir non-recursively (if they are not already