[wp-trac] [WordPress Trac] #50324: Can't create new blog in multisite if database insert happens on clean_site_cache

[WordPress Trac]

#50324: Can't create new blog in multisite if database insert happens on
clean_site_cache
--------------------------------+-----------------------------
 Reporter:  trepmal             |      Owner:  (none)
     Type:  defect (bug)        |     Status:  new
 Priority:  normal              |  Milestone:  Awaiting Review
Component:  Networks and Sites  |    Version:  5.3
 Severity:  normal              |   Keywords:
  Focuses:  multisite           |
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 In multisite, you cannot create a new blog if there is a database insert
 happening on the `clean_site_cache` action.

 Introduced in r45910

 https://core.trac.wordpress.org/browser/trunk/src/wp-includes/ms-
 site.php#L68-L74

 On L68, the blog data is inserted into the blogs table. The new blog ID is
 in `$wpdb->insert_id`. This ID is then needed shortly after at L74 to get
 the WP_Site object.
 However, `clean_blog_cache()` has an action hook. If something hooked in
 there does a database insert, the value of `$wpdb->insert_id` changes.
 This is likely to cause a `Could not retrieve site data.` but there are
 some other scenarios:

 - If `$wpdb->insert_id` does not match any blog ID: `Error: Could not
 retrieve site data.`

 - If `$wpdb->insert_id` matches a valid blog: potentially perform actions
 against the wrong blog. Anything run on wp_initialize_site will run
 against the preexisting blog, not the newly created one.

 - If `$wpdb->insert_id` matches a half-installed blog (such as from case
 1): The original blog will be fully installed since L74 now returns
 truthy. However, there will be some mixed values (`home`/`siteurl` will
 match wp_blogs values of older site, `blogname` will match the newly
 created blog.)

 - If `$wpdb->insert_id` matches by pure chance the correct blog_id: Task
 failed successfully.

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Ticket URL: <https://core.trac.wordpress.org/ticket/50324>
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