src/PEAR/DependencyDB.php
function assertDepsDB()
    {
        if (!is_file($this->_depdb)) {
            $this->rebuildDB();
            return;
        }

        $depdb = $this->_getDepDB();
        // Datatype format has been changed, rebuild the Deps DB
        if ($depdb['_version'] < $this->_version) {
            $this->rebuildDB();
        }

        if ($depdb['_version']{0} > $this->_version{0}) {
            return PEAR::raiseError('Dependency database is version ' .
                $depdb['_version'] . ', and we are version ' .
                $this->_version . ', cannot continue');
        }
    }
function assertDepsDB()
    {
        if (!is_file($this->_depdb)) {
            $this->rebuildDB();
            return;
        }

        $depdb = $this->_getDepDB();
        // Datatype format has been changed, rebuild the Deps DB
        if ($depdb['_version'] < $this->_version) {
            $this->rebuildDB();
        }

        if ($depdb['_version']{0} > $this->_version{0}) {
            return PEAR::raiseError('Dependency database is version ' .
                $depdb['_version'] . ', and we are version ' .
                $this->_version . ', cannot continue');
        }
    }
Create the dependency database, if it doesn't exist.  Error if the database is
newer than the code reading it.
@return void|PEAR_Error