wp_get_active_network_plugins() can generate a needless query
|Reported by:||nacin||Owned by:||ryan|
In #18955, we stopped caching the default value when get_site_option() was called on an option that does not exist.
This introduces a situation where active_sitewide_plugins may be queried for on every pageload.
- active_sitewide_plugins should be instantiated in populate_network() and added to upgrade_network().
- wp_load_core_site_options() should be set up to cache as false any keys it misses. As this only works when an external object cache is not at play, it basically becomes a rudimentary not-options cache. (See #19008.)
Point 1 is for 3.3. Point 2 is a general nice-to-have.