WP_Query found_posts inconsistent data type.

[PressLabs]

You can remove the patch that has the mismatching ticket number, my bad.

[birgire]

Thanks for the patch @PressLabs.

The database query returns a string, so this seems a valid concern.

I checked the other query classes and they also convert it to integer.

In WP_Comment_Query we see:

$found_comments_query = apply_filters( 'found_comments_query', 'SELECT FOUND_ROWS()', $this );
 
$this->found_comments = (int) $wpdb->get_var( $found_comments_query );

and in WP_Site_Query we have:

$found_sites_query = apply_filters( 'found_sites_query', 'SELECT FOUND_ROWS()', $this );
 
$this->found_sites = (int) $wpdb->get_var( $found_sites_query );

Similarly in WP_User_Query:

$this->total_users = (int) $wpdb->get_var( apply_filters( 'found_users_query', 'SELECT FOUND_ROWS()' ) );

I would suggest making it more readable and change:

$this->found_posts = intval( $wpdb->get_var( apply_filters_ref_array( 'found_posts_query', array( 'SELECT FOUND_ROWS()', &$this ) ) ) );

to

$found_posts_query = apply_filters_ref_array( 'found_posts_query', array( 'SELECT FOUND_ROWS()', &$this ) );

$this->found_posts = (int) $wpdb->get_var( $found_posts_query );

in WP_Query.

[PressLabs]

I'm unsure what the stance is on the matter, but do you in core enforce type casting on apply_filter or is it too defensive and out of scope.

I'm asking because for me it would be reasonable if I got an int I should return an int but in the PHP world things grow hazy on the matter.

Should I cast also the found_posts filter a couple of lines below, as well?

[birgire]

I added a type test in 42469.2.diff​ and removed some extra tabs.

There are some cases in core with (int) apply_filters( ... ); so I don't think that's a problem with that structure. It sounds logical to convert the output from the found_posts filter to integer as well, as the definition of the found_posts property says it's of type int:

/**
 * The amount of found posts for the current query.
 *
 * If limit clause was not used, equals $post_count.
 *
 * @since 2.1.0
 * @var int
 */
public $found_posts = 0;

I added the int cast on the found_posts filter in 42469.3.diff​, with an extra test.

But the general concern is if anyone out there is assuming that found_posts is a string, for example:

if( '1' === $query->found_posts ) {
   // ...
}

So I tagged the ticket with dev-feedback.

[SergeyBiryukov]

In 48328:

Query: Make sure the found_posts property of WP_Query is always an integer, to match the documented type.

This makes the property consistent with similar properties of other classes:

• WP_Comment_Query::$found_comments
• WP_Network_Query::$found_networks
• WP_Site_Query::$found_sites
• WP_User_Query::$total_users

Props birgire, PressLabs.
Fixes #42469.

[desrosj]

This received a call out in the Miscellaneous Developer Changes in 5.5 dev note: ​https://make.wordpress.org/core/2020/07/29/miscellaneous-developer-focused-changes-in-wordpress-5-5/.