[wp-trac] [WordPress Trac] #45157: Upgrading from 4.9.9 to 5.0-alpha-43815 with Gutenberg plugin installed gets whitescreen of death

[WordPress Trac]

#45157: Upgrading from 4.9.9 to 5.0-alpha-43815 with Gutenberg plugin installed
gets whitescreen of death
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 Reporter:  timhibberd    |       Owner:  (none)
     Type:  defect (bug)  |      Status:  new
 Priority:  normal        |   Milestone:  5.0
Component:  General       |     Version:  5.0
 Severity:  major         |  Resolution:
 Keywords:  needs-patch   |     Focuses:
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Comment (by mcsf):

 > I also get a fatal when coming from bleeding edge nightlies (
 5.1-something or other ) and the Gutenberg plugin is active.

 @TimothyBlynJacobs, this is less surprising, though. I assume you were
 running a nightly after r43765? Which exact version of the plugin were you
 running? If you ''weren't'' running a nightly later than 43765 then I have
 no clue what would've caused the plugin not to deactivate.

 In any case, the failure seems to be the same for both reports.

 > Cannot redeclare class WP_REST_Blocks_Controller
 >
 > File: /var/www/wordpress/wp-content/plugins/gutenberg/lib/class-wp-rest-
 blocks-controller.php on line 0

 The issue here is related to
 [https://github.com/WordPress/gutenberg/issues/10822#issuecomment-431563910
 gb10822], in which the plugin's declaration is hit before the one in core,
 so any `class_exists` check in the plugin is useless.

 I think the only way forward now, if we want to be safe, is to finally
 switch the plugin to requiring 5.0.0 as the minimum WP version and
 removing all the declarations that core already provides.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/45157#comment:13>
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