The post_limits Hook in WPFTS

The post_limits hook in WordPress is a filter that allows modification of the SQL LIMIT clause used to restrict the number of posts selected. WPFTS uses this hook to store the original LIMIT value, set by WordPress, in the WP_Query session. This is necessary for the correct operation in split_the_query mode.

What WPFTS does when post_limits is called:

1. Saving the original LIMIT value: WPFTS saves the value passed to the post_limits filter in the session $wpq->wpftsi_session['limits']. This is the original LIMIT value set by WordPress or other plugins.

2. Returning the original value: The plugin returns the original LIMIT value unchanged. This means that WPFTS does not directly modify the post count limit in the query at this hook.

Important functions involved in post_limits processing:

• WPFTS_Search::index_post_limits()

How to use this in addon development:

Addon developers working with pagination and WPFTS need to understand that the plugin saves the original LIMIT value and does not change it at this hook. Modification of LIMIT in WPFTS occurs at later stages of query processing, specifically in the WPFTS_Search::index_posts_fields() method, where it is determined whether to use a split query. If your addon also modifies LIMIT, ensure that your logic does not conflict with WPFTS.

Additional notes:

• WPFTS uses the saved LIMIT value to determine the split query mode and for correct pagination operation.

• This hook is called for all WP_Query queries, but WPFTS only processes it for queries related to search.