$wp_query->found_posts is set to 0 with posts_per_page=-1

[patrik bona]

If I modify/create new WP_Query object with parameter posts_per_page=-1 (or showposts=-1), then $wp_query->found_posts has incorrect value. It always return 0 instead of count of found posts.

If I don't set posts_per_page, or set it to some positive number, then it is set to correct value.

http://core.trac.wordpress.org/browser/trunk/wp-includes/query.php?rev=17610#L2633

If $limits is empty, we should do a count() on $this->posts. Unsure whether we should aim to avoid the count when no_found_rows is true, as I imagine that's just looking out for the extra query.

I think we should avoid the count: In my mind, "no_found_rows" signals that you're not interested in the total number of posts.

Related: http://core.trac.wordpress.org/ticket/10964#comment:77

patch also removes apply_filters_ref_array

Related: #17195

Punted per bug scrub.

Related: #14426, #21147

My reading of $q['no_found_rows'] is "don't do the FOUND_ROWS() query" - doesn't mean that found_rows is forbidden from being set, just don't use the query to do it. The query is also suppressed if there is no limit, which to me means "set found_rows from count( $posts ) since we got all of the posts already"

I made a new patch that IMO is simpler and addresses the original purpose of the ticket which is returning a number that isn't zero in an instance like this:

$q = new WP_Query( array( 'posts_per_page' => -1 ) );
error_log( $q->found_posts );
exit();

Updated patch to populate a property that the object actually contains.

Suggest merging with #14426.

Sergey's patch on #14426 does the trick