Category page shows only 1 post when that post has more than 1 category?

Question

The error I'm seeing is that the way I currently have my category page set up, if a post on that page has more than 1 category, the loop won't load the posts that follow the one with multiple categories.

Currently I have about 10 posts in my test installation of WordPress. 9 of them have the same category, lets call it "Surprised". 1 of them has 3 categories. When I go to the category for page "Surprised, instead of seeing 10 posts on that page, including the one with 3 different categories, the page stops loading the category posts that follow it.

Here is an example of one of the loops that ate on the category page (there are 4 loops total and all of them behave the same presently).

<? get_header(); ?>

<?
$cat_array = get_the_category();
$cat_name = esc_html($cat_array[0]->name);
?>
    <?
    $paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
    $args  = array(
      'category_name'  => $cat_name,
      'paged'          => $paged,
      'posts_per_page' => 2
    );
    $wp_query = new WP_Query($args);
    while($wp_query->have_posts()) : $wp_query->the_post(); ?>
    <div class="post-box pane">
      <a href="<? the_permalink(); ?>" class="article">
        <h3 class="title"><? echo get_the_title(); ?></h3>
        <? echo the_post_thumbnail('smaller-general-thumb', array('class' => 'thumb')) ?>
      </a>
    </div>
    <? endwhile; wp_reset_postdata(); ?>

The reason I'm doing 4 sections with different loops is because each section has a specific number of posts in it. I have to limit the number of posts that show for a section, so I create a new loop and I limit the posts for that loop by paging them and limiting posts per page.

Answer 1

Multiple Loops

Outside the loop you can get available terms of the core taxonomy category with get_terms( 'taxonomy_name' ). The resulting array contains objects like

object(stdClass)#141 (9) {
    ["term_id"] => string(1) "3"
    ["name"] => string(9) "The Name of your Category"
    ["slug"] => string(9) "name-of-tax-term"
    ["term_group"] => string(1) "0"
    ["term_taxonomy_id"] => string(1) "3"
    ["taxonomy"] => string(11) "slug_of_tax"
    ["description"] => string(41) "Description of Term."
    ["parent"] => string(1) "0"
    ["count"] => string(1) "3"
}

So you would want to get the category slug, not its name:

$cats = get_terms( 'category' );

You could then loop the categories like

foreach ( $cats as $cat ) {
    $args  = array(
      'category_name'  => $cat->slug,
      'paged'          => $paged,
      'posts_per_page' => 2
    );
    // the loop
    wp_reset_postdata();
}

One Loop

If your loop runs on the unchanged main query, the current category is already present in the query.

Just change

$args  = array(
  'category_name'  => $cat_name,
  'paged'          => $paged,
  'posts_per_page' => 2
);

to

$args  = array(
  'paged'          => $paged,
  'posts_per_page' => 2
);

in your code.

Besides, when not using get_the_category() inside the loop, you have to pass a post ID as argument.

Answer 2

This is the solution I found to be the most elegant and appropriate for my situation:

<? global $wp_query; ?>

$args  = array_merge( $wp_query->query_vars, array( 'posts_per_page' => 2));
$the_query = new WP_Query($args);
while($the_query->have_posts()) : $the_query->the_post(); ?>

/// The loop

<? endwhile; rewind_posts(); ?> 

I specifically decided to use array_merge in order to merge the global query with the loop I'm writing in order to limit the number of posts for that loop. Now I don't need to specify the category since that's already in the global query. No need to update dat bish myself.

Thank you everyone for your help!