Which method will have higher priority? - wordpress

Question

There are two approaches for limiting revisions in WordPress; WP_POST_REVISIONS and wp_revisions_to_keep(). Which will have higher priority ? I could not understand even after reading codex.

Answer 1

WP_POST_REVISIONS is constant, not a function. if you have set WP_POST_REVISIONS like this: define( 'WP_POST_REVISIONS', 3 ); then you'll get 3 when you'll call the function wp_revisions_to_keep (provided that there is no filter who is modifying the value). If WP_POST_REVISIONS is not set then it will store every revision and you'll get -1 when you'll call wp_revisions_to_keep. This is the source code of wp_revisions_to_keep.
/**
* Determine how many revisions to retain for a given post.
* By default, an infinite number of revisions are stored if a post type supports revisions.
*
* #since 3.6.0
*
* #uses post_type_supports()
* #uses apply_filters() Calls 'wp_revisions_to_keep' hook on the number of revisions.
*
* #param object $post The post object.
* #return int The number of revisions to keep.
*/
function wp_revisions_to_keep( $post ) {
$num = WP_POST_REVISIONS;
if ( true === $num )
$num = -1;
else
$num = intval( $num );
if ( ! post_type_supports( $post->post_type, 'revisions' ) )
$num = 0;
return (int) apply_filters( 'wp_revisions_to_keep', $num, $post );
}
From this, it is clear that function wp_revisions_to_keep() uses WP_POST_REVISIONS inside it. However, to be 100% sure that your suggested number of revisions work then you should hook a function to wp_revisions_to_keep. Something like this:-
add_filter('wp_revisions_to_keep', 'custom_revisions_number', 10, 2);
function custom_revisions_number($num, $post) {
$num = 5; // <---- change this accordingly.
return $num;
}
Highest priority is of the hook that will execute last.