Invalidate post cache when a user is removed from a blog

[nprasath002]

In remove_user_from_blog invalidate post cache when a user is removed from a blog

[wonderboymusic]

Good catch, @nprasath002. I added a new patch here: 25545.diff​

[wonderboymusic]

.2.diff adds a unit test.

[wonderboymusic]

In 27087:

Invalidate the post cache for posts associated with a user who has been removed from a blog in remove_user_from_blog(). Adds a unit test.

Props nprasath002 for the initial patch.
Fixes #25545.

[TobiasBg]

Would array_walk( $post_ids, 'clean_post_cache' ); be more appropriate here than array_map(...), to make it clearer that we don't expect/need the return array?

[kovshenin]

In r27087 you're invalidating caches for all the existing posts of the receiving user. We really just need the ones that belong(ed) to the user being removed. Also this seems like a no-brainer for links as well and since they're still in core, let's clean those caches too. See 25545.3.diff​.

[wonderboymusic]

In 27152:

Collect the post and link ids that will be reassigned before running the update in remove_user_from_blog(). Use array_walk() instead of array_map() when invalidating the caches for the collected ids.

Props kovshenin.
Fixes #25545.

[kovshenin]

Hi, sorry :) I'm having second thoughts about the INs in the queries in r27152, even though they're probably faster, they won't scale with large amounts of posts. Let's change those back. See 25545.4.diff​.

[wonderboymusic]

In 27161:

In remove_user_from_blog(), avoid a potentially expensive IN query before invalidating the reassigned post and link caches.

Props kovshenin.
Fixes #25545. (Again.)

[barry]

There is a typo in r27152. There is no ID field in the links table. The primary key is link_id

[nacin]

In 27834:

Use correct column name. See [27152].

props barry.
fixes #25545.