Add get and set methods to WP_User_Query

[wonderboymusic]

User queries are confusing to alter, so it would be helpful to have get and set methods a la WP_Query when altering WP_User_Query::query_vars in a filter or action.

do_action_ref_array( 'pre_user_query', array( &$this ) );

Without these methods, you have to do things like:

$query->query_vars[ 'meta_query' ] = array( $memory_hog );

Instead of:

$query->set( 'meta_query', array( $memory_hog )  );

I personally don't find WP_Query->set() and WP_Query->get() all that useful, but I do use them, so I don't know. +1 for consistency, I guess.

One thing I don't like about WP_Query::get() is that it returns an empty string, rather than something like null or false. See #19243. It would be nice if we changed how WP_Query::get() works in the process.

False or null for when it isn't set?

I like functions to return absolutely nothing in those cases, but you pick false / null if there's a consistency issue with WP_Query

null would be the same as absolutely nothing, so that's fine. I may try to convert WP_Query::get() over to null in the future.

21426.diff​ — could use some basic unit tests.

I am noticing this trend

Attached tests - adds query.php to tests/user in Unit Tests

In [21995]:

Add get() and set() methods to WP_User_Query for modifying query variables the way you might with WP_Query. props wonderboymusic. fixes #21426.

​[UT1047]