update_retrieve_dependencies

update_retrieve_dependencies()

function update_retrieve_dependencies() {
  $return = array();
  // Get a list of installed modules, arranged so that we invoke their hooks in
  // the same order that \Drupal::moduleHandler()->invokeAll() does.
  foreach (\Drupal::keyValue('system.schema')->getAll() as $module => $schema) {
    if ($schema == SCHEMA_UNINSTALLED) {
      // Nothing to upgrade.
      continue;
    }
    $function = $module . '_update_dependencies';
    // Ensure install file is loaded.
    module_load_install($module);
    if (function_exists($function)) {
      $updated_dependencies = $function();
      // Each implementation of hook_update_dependencies() returns a
      // multidimensional, associative array containing some keys that
      // represent module names (which are strings) and other keys that
      // represent update function numbers (which are integers). We cannot use
      // array_merge_recursive() to properly merge these results, since it
      // treats strings and integers differently. Therefore, we have to
      // explicitly loop through the expected array structure here and perform
      // the merge manually.
      if (isset($updated_dependencies) && is_array($updated_dependencies)) {
        foreach ($updated_dependencies as $module_name => $module_data) {
          foreach ($module_data as $update_version => $update_data) {
            foreach ($update_data as $module_dependency => $update_dependency) {
              // If there are redundant dependencies declared for the same
              // update function (so that it is declared to depend on more than
              // one update from a particular module), record the dependency on
              // the highest numbered update here, since that automatically
              // implies the previous ones. For example, if one module's
              // implementation of hook_update_dependencies() required this
              // ordering:
              //
              // system_update_8002 ---> user_update_8001
              //
              // but another module's implementation of the hook required this
              // one:
              //
              // system_update_8003 ---> user_update_8001
              //
              // we record the second one, since system_update_8002() is always
              // guaranteed to run before system_update_8003() anyway (within
              // an individual module, updates are always run in numerical
              // order).
              if (!isset($return[$module_name][$update_version][$module_dependency]) || $update_dependency > $return[$module_name][$update_version][$module_dependency]) {
                $return[$module_name][$update_version][$module_dependency] = $update_dependency;
              }
            }
          }
        }
      }
    }
  }

  return $return;
}