[wp-trac] [WordPress Trac] #54969: PHP Fatal error when upgrading WordPress to 5.9

[WordPress Trac]

#54969: PHP Fatal error when upgrading WordPress to 5.9
-----------------------------+-----------------------------
 Reporter:  garak734         |      Owner:  (none)
     Type:  defect (bug)     |     Status:  new
 Priority:  normal           |  Milestone:  Awaiting Review
Component:  Upgrade/Install  |    Version:  5.9
 Severity:  blocker          |   Keywords:
  Focuses:                   |
-----------------------------+-----------------------------
 Clicked on manual upgrade link on dashboard to upgrade from 5.8.2 to
 Version 5.9-en_GB.

 Message on screen: There has been a critical error on this website.

 Error message in debug.log:

 PHP Fatal error:  Uncaught Error: Call to a member function
 switch_to_blog() on null in C:\wamp64\www\xxxxxx\wordpress\wp-
 includes\cache.php:239
 Stack trace:
 #0 C:\wamp64\www\xxxxxx\wordpress\wp-includes\load.php(727):
 wp_cache_switch_to_blog(1)
 #1 C:\wamp64\www\xxxxxx\wordpress\wp-settings.php(131):
 wp_start_object_cache()
 #2 C:\wamp64\www\xxxxxx\wordpress\wp-config.php(116):
 require_once('C:\\wamp64\\www\\x...')
 #3 C:\wamp64\www\xxxxxx\wordpress\wp-load.php(50):
 require_once('C:\\wamp64\\www\\x...')
 #4 C:\wamp64\www\xxxxxx\wordpress\wp-admin\upgrade.php(18):
 require('C:\\wamp64\\www\\x...')
 #5 {main} thrown in C:\wamp64\www\xxxxxx\wordpress\wp-includes\cache.php
 on line 239

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Ticket URL: <https://core.trac.wordpress.org/ticket/54969>
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