relationships-problem-demo.php

<?php

  // Include this page in your functions.php
  // Flush permalinks
  // Create 1 Recipe
  // Create 1 Brand
  // Create 1 Cheese
  // On your recipe, associate created brand and created cheese
  // Adapt id's on adaptQuery function with correct ids
  // Go to "http://www.domain.com/recipe/
  // You will see "Nothing here"
  // If you comment $brand or $cheese, you will "see" your created recipe
  // If you change AND by OR, you will see your created recipe twice

  add_action('init', 'createCustomPostType', 10);
  add_action('mb_relationships_init', 'myRelationships', 10);
  add_action('parse_query', 'adaptQuery', 5, 1);

  function createCustomPostType(){

    $labels = array(
      'name' => 'Recipes',
      'singular_name' => 'Recipe',
      'menu_name' => 'Recipes',
    );

    $args = array(
      'labels' => $labels,
      'description' => 'Recipes',
      'public' => true,
      'publicly_queryable' => true,
      'show_ui' => true,
      'show_in_menu' => true,
      'query_var' => true,
      'capability_type' => 'post',
      'has_archive' => true,
      'hierarchical' => false,
      'menu_position' => null,
      'supports' => array(
          'title',
          'editor',
      )
    );

    register_post_type('recipe', $args);

    $labels = array(
      'name' => 'Brands',
      'singular_name' => 'Brand',
      'menu_name' => 'Brands',
    );

    $args = array(
      'labels' => $labels,
      'description' => 'Brands',
      'public' => true,
      'publicly_queryable' => true,
      'show_ui' => true,
      'show_in_menu' => true,
      'query_var' => true,
      'capability_type' => 'post',
      'has_archive' => false,
      'hierarchical' => false,
      'menu_position' => null,
      'supports' => array(
          'title',
          'editor',
      )
    );

    register_post_type('brand', $args);

    $labels = array(
      'name' => 'Cheeses',
      'singular_name' => 'Cheese',
      'menu_name' => 'Cheeses',
    );

    $args = array(
      'labels' => $labels,
      'description' => 'Cheeses',
      'public' => true,
      'publicly_queryable' => true,
      'show_ui' => true,
      'show_in_menu' => true,
      'query_var' => true,
      'capability_type' => 'post',
      'has_archive' => false,
      'hierarchical' => false,
      'menu_position' => null,
      'supports' => array(
          'title',
          'editor',
      )
    );

    register_post_type('cheese', $args);

  }

  function myRelationships(){

    MB_Relationships_API::register( [
      'id'   => 'recipes_to_brands',
      'from' => 'recipe',
      'to'   => 'brand',
    ]);

    MB_Relationships_API::register( [
      'id'   => 'cheeses_to_recipes',
      'from' => 'cheese',
      'to'   => 'recipe',
    ]);

  }

  function adaptQuery($query){

    if ( !is_admin() && $query->is_main_query() ) {

      if ( is_post_type_archive('recipe')) {

        $cheese = 17; // My cheese ID
        $brand = 18; // My brand ID
          
        $relationShipArgs = [];
    
        if(isset($brand)):
          $relationShipArgs[] = [
            'id'   => 'recipes_to_brands',
            'to' => $brand,
          ];
        endif;

        if(isset($cheese)):
          $relationShipArgs[] = [
            'id'   => 'cheeses_to_recipes',
            'from' => $cheese,
          ];
        endif;
  
        if(sizeof($relationShipArgs) > 0):
          $relationShipArgs['relation'] = 'AND';
          $query->set('relationship', $relationShipArgs);
        endif;
  
      }
    }
  
    return $query;

  }