error 404 on pagination on homepage

Question

I have a blog Post home page with the following code in home.php:

<div id="primary">
<div id="content" role="main">
<h2 class="page-title">Featured Products</h2>
<?php 
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
wp_reset_query();
mp_display_products('&post_type=product&paged=' . $paged, $display) ; ?>

<div class="clear index-space"></div>
 </div><!-- #content -->
</div><!-- #primary -->

Now the homepage works just fine, but the ?paged=2 throws an error 404. Don't know why. In products categories the pagination works fine too.

Any help would be appreciated.

//EDIT

Here is a paste of the function mp_display_products()

Thanks

Answer 1

Change the line in which you set the variable $paged as follows:

$paged = (get_query_var('page')) ? get_query_var('page') : 1;

And maybe do a wp_reset_query(); before the mentioned line as well (depending on what else is going on in your theme).

// Edit

Here's what I did (and what worked):

$paged = (get_query_var('page')) ? get_query_var('page') : 1;
$args = array (
    'category_name' =>'news',
    'posts_per_page' => 5,
    'paged'=>$paged,
); 
query_posts($args);
while (have_posts()) : the_post();
    the_title(); echo ' — '; the_content();
endwhile;

Both ?page=2 and /2 appended onto the URL led to the second page. Maybe you could give the exact code you are using for testing?

Answer 2

To understand why 404 erros occur with pagination, you have to first understand the process WordPress follows when a page is requested.

The query is parsed and the results are queried from the database before the template is loaded. When you create a new query in the template, these results are unrelated to the original query. Whether or not there are additional pages, and how many pages exists, is based on the original default main query, WordPress has no "awareness" of your new custom query in the template.

So the way to fix this is to modify that original query before it is sent to the database via the pre_get_posts action rather than calling query_posts in the template.

function wpa89392_homepage_products( $query ) {
    if ( $query->is_home() && $query->is_main_query() ) {
        $query->set( 'post_type', array( 'product' ) );
    }
}
add_action( 'pre_get_posts', 'wpa89392_homepage_products' );