WP_Post:get_instance: Update cache if $_post->filter is empty

[greencp]

WP_Post::get_instance always returns raw filtered posts. At least in my tests it gets many hits where a post is already cached, but not filtered. For each hit it calls sanitize_post again.

To improve performance, if a cached post isn't filtered, update the cache after calling sanitize_post.

class-wp-post.php, line 228:

Instead of

} elseif ( empty( $_post->filter ) ) {
  $_post = sanitize_post( $_post, 'raw' );
}

add wp_cache_replace

} elseif ( empty( $_post->filter ) ) {
  $_post = sanitize_post( $_post, 'raw' );
  wp_cache_replace( $_post->ID, $_post, 'posts' );
}

This significantly reduces unnecessary calls to sanitize_post.

[Soean]

Implements the code from the description.

[crstauf]

Yes please...?