[wp-trac] [WordPress Trac] #23290: When using switch_to_blog() with a persistent object cache that lacks wp_cache_switch_to_blog() support, non-persistent groups are not maintained

[WordPress Trac]

#23290: When using switch_to_blog() with a persistent object cache that lacks
wp_cache_switch_to_blog() support, non-persistent groups are not maintained
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 Reporter:  markjaquith              |       Owner:
     Type:  defect (bug)             |      Status:  new
 Priority:  normal                   |   Milestone:  3.6
Component:  Cache                    |     Version:  3.0
 Severity:  normal                   |  Resolution:
 Keywords:  has-patch needs-testing  |
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Changes (by ethitter):

 * keywords:   => has-patch needs-testing


Comment:

 @stevenkword and I worked on
 [http://core.trac.wordpress.org/attachment/ticket/23290/23290.patch
 23290.patch] during the Boston WP Hack Day.

 We introduced a `get_non_persistent_groups()` method in Core's
 `WP_Object_Cache` to handle the core use, and to be implemented by authors
 of object cache drop ins. Initially we tried to include universal support
 for getting the non-persistent cache groups, but review of the APC Object
 Caching plugin revealed that the structure of `$global_groups` can vary
 between persistent backends.

 The switching fallback that was present in `switch_to_blog()` and
 `restore_current_blog()` was abstracted into `_ms_cache_switch_fallback()`
 for consistency, and logic to use the persistent group getter closely
 mirrors the handling of global groups already in those functions.

-- 
Ticket URL: <http://core.trac.wordpress.org/ticket/23290#comment:5>
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