get_blog_option queries DB on default blog_id

[wpmuguru]

If get_blog_option is passed null for a blog_id, it queries the DB instead of using the current blog option cache.

In most, if not all, of the MS specific functions that have a $blog_id, if $blog_id is null, the current blog is used.

patch is attached.

The $wpdb->get_blog_prefix( ... will return the prefix for the current blog when null is passed. So, the current implementation defaults to the current blog but queries the DB instead of retrieving from cache.

Added test cases for a slew of changes about to drop: ​[UT436].

In [18662]:

Allow get_blog_option(null,...) to hit the cache for the current blog. New return values for add_blog_option, update_blog_option, delete_blog_option. Don't set the cache in those functions if add/update/delete_option failed. see #17883.

Sorry wpmuguru, tried to stop the commit to include props. Thanks for the contribution as always :-)

Leaving this open so ryan can review it.

Replying to nacin:

Sorry wpmuguru, tried to stop the commit to include props. Thanks for the contribution as always :-)

No problem - I've done the same.