Add taxonomy hierarchy (parent and child) matching to Advanced Custom Fields

acf_taxonomy_hierarchy.php

<?php

function add_child_and_parent_to_acf_taxonomy_choices($choices) {
  $tax_choices = array();
  foreach($choices as $taxonomy => $c) {
    $tax_choices[$taxonomy] = $c;
    if($taxonomy != 'all' && is_taxonomy_hierarchical($taxonomy)) {
      $tax_choices[$taxonomy.'-tax_parent'] = $c.' (parent)';
      $tax_choices[$taxonomy.'-tax_child'] = $c.' (child)';
    }
  }
  return $tax_choices;
}
add_filter('acf/location/rule_values/taxonomy', 'add_child_and_parent_to_acf_taxonomy_choices');

function child_and_parent_taxonomy_matching_for_acf($match, $rule, $options) {
  global $tag_ID;
  $taxonomy = $options['taxonomy'];

  if(!$taxonomy) {
    return false;
  }

  if($tag_ID) {
    $term_obj = get_term($tag_ID, $taxonomy);

    $tax_rule = str_replace($taxonomy.'-', '', $rule['value']);

    if($tax_rule == 'tax_parent') {
      if($rule['operator'] == "==") {
        $match = !$term_obj->parent;
      } elseif($rule['operator'] == "!=") {
        $match = $term_obj->parent;
      }
    } elseif($tax_rule == 'tax_child') {
      if($rule['operator'] == "==") {
        $match = $term_obj->parent;
      } elseif($rule['operator'] == "!=") {
        $match = !$term_obj->parent;
      }
    }
  } else {
    if($rule['operator'] == "==" ) {
      $match = ($taxonomy == $rule['value']);
      if($rule['value'] == "all") {
        $match = true;
      }
    } elseif($rule['operator'] == "!=") {
      $match = ($taxonomy != $rule['value']);
      if($rule['value'] == "all") {
        $match = false;
      }
    }
  }
  return $match;
}
add_filter('acf/location/rule_match/taxonomy', 'child_and_parent_taxonomy_matching_for_acf', 10, 3);