Sort a Drupal graph into chunks of dependencies that can be installed concurrently

chunk_graph.php

<?php

use Drupal\Component\Graph;

function chunk_graph(Graph $graph_object) {
  // Sort the graph by weight.
  $graph = $graph_object->searchAndSort();
  uasort($graph, 'Drupal\Component\Utility\SortArray::sortByWeightElement');
  // Ensure that graph nodes are sorted from least to most edges.
  $graph = array_reverse($graph);
  $all_imported = [];
  $chunked_graph = [];
  // Traverse the ordered graph and chunk it into sets that can be installed
  // concurrently.
  while ($graph) {
    $chunk = [];
    foreach ($graph as $i => $node) {
      $edges = array_keys($node['edges']);
      if (count(array_intersect($edges, $all_imported)) === count($edges)) {
        $chunk[] = $i;
        unset($graph[$i]);
      }
    }
    $all_imported = array_merge($all_imported, $chunk);
    $chunked_graph[] = $chunk;
  }
  return $chunked_graph;
}