[wp-trac] [WordPress Trac] #27855: Database errors when promoting WP 3.9 to multisite

[WordPress Trac]

#27855: Database errors when promoting WP 3.9 to multisite
-------------------------------+------------------------------
 Reporter:  l3rady             |       Owner:
     Type:  defect (bug)       |      Status:  closed
 Priority:  normal             |   Milestone:  Awaiting Review
Component:  Database           |     Version:  3.7
 Severity:  normal             |  Resolution:  invalid
 Keywords:  reporter-feedback  |     Focuses:
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Comment (by johnjamesjacoby):

 This is a bummer.

 In BuddyPress, we've taken precautions to:

 * Avoid creating a new `wp_signups` table it already multisite
 * Avoid creating a new `wp_signups` table if it already exists is some
 other way
 * Create exactly the same `wp_signups` table that WordPress Multisite
 would make
 * Use dbDelta alter any existing table to match WordPress core's schema if
 necessary

 Is it possible dbDelta isn't capable of handling this particular
 difference (hence why it was added to `pre_schema_upgrade()` in r25179?)
 If so, we will need to add extra checks in BuddyPress and include a
 similar `pre_schema_upgrade()` routine to run this for single-site
 installations. (It's an odd bit of integration with a niche application,
 but if it's something we can check for, I believe we should be doing so.)

 Other alternatives:
 * Improve dbDelta (I'm only mildly afraid to stab that dragon)
 * Remove multisite checks from `pre_schema_upgrade()` and instead check
 for `$wpdb->signups` and/or `$wpdb->get_results( "DESCRIBE
 {$wpdb->base_prefix}signups};" )` along with another version bump to rerun
 those `ALTER`s.

 Today, this falls in BuddyPress's court to fix; we're going outside-of-
 the-wp_box to improve sign-ups. Tomorrow, since 2 plugins are solving this
 problem the same way, WordPress single-site should reconsider how sign-ups
 happen, likely adopting multisite's approach. (Ideally, single-site gets
 phased out completely in favor of multisite as the default experience, but
 that's a 5 year plan that warrants its own ticket.)

 I'm comfortable closing this here, and moving discussion on the fix next-
 door to [https://buddypress.trac.wordpress.org/ticket/5563 BuddyPress's
 trac.]

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Ticket URL: <https://core.trac.wordpress.org/ticket/27855#comment:9>
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