Function check_not_current_branch

builtin/fetch.c:1495–1505

}

static void check_not_current_branch(struct ref *ref_map)
{
	const char *path;
	for (; ref_map; ref_map = ref_map->next)
		if (ref_map->peer_ref &&
		    starts_with(ref_map->peer_ref->name, "refs/heads/") &&
		    (path = branch_checked_out(ref_map->peer_ref->name)))
			die(_("refusing to fetch into branch '%s' "
			      "checked out at '%s'"),
			    ref_map->peer_ref->name, path);
}

static int truncate_fetch_head(void)
{