phorge-arcanist/src/utils/PhutilDirectedScalarGraph.php

<?php

/**
 * Concrete subclass of @{class:AbstractDirectedGraph} which can not load any
 * data from external sources.
 */
final class PhutilDirectedScalarGraph extends AbstractDirectedGraph {

  protected function loadEdges(array $nodes) {
    throw new Exception(
      pht(
        '%s can not load additional nodes at runtime. Tried to load: %s',
        __CLASS__,
        implode(', ', $nodes)));
  }

}