After I autoupdated from 1.2.0 to 1.2.1 I saw the following message. Also to link to the Piwik forum was not working (forwarded me to the backend). Besides this the update seemed to work.
There is an error. Please report the message and full backtrace in the Piwik forums. Notice: Undefined property: Piwik_CoreUpdater_Controller::$pathRootExtractedPiwik in /var/www/vhost1/gpgtools/www/piwik-1.2/plugins/CoreUpdater/Controller.php on line 99 Backtrace --> <a href='/0'>#0</a> Piwik_ErrorHandler(8, Undefined property: Piwik_CoreUpdater_Controller::$pathRootExtractedPiwik, /var/www/vhost1/gpgtools/www/piwik-1.2/plugins/CoreUpdater/Controller.php, 99, Array ()) called at [/var/www/vhost1/gpgtools/www/piwik-1.2/plugins/CoreUpdater/Controller.php:99]<a href='/1'>#1</a> Piwik_CoreUpdater_Controller->oneClick_Unpack() called at [/var/www/vhost1/gpgtools/www/piwik-1.2/plugins/CoreUpdater/Controller.php:63]<a href='/2'>#2</a> Piwik_CoreUpdater_Controller->oneClickUpdate()<a href='/3'>#3</a> call_user_func_array(Array ( => Piwik_CoreUpdater_Controller Object ( => , => Array (), => Array (), => Array (), => CoreUpdater, => , => , => 0, => Piwik_Site Object ( => 0),[newVersion] => 1.2.1,[pathPiwikZip] => /var/www/vhost1/gpgtools/www/piwik-1.2/tmp/latest/latest.zip), => oneClickUpdate), Array ()) called at [/var/www/vhost1/gpgtools/www/piwik-1.2/core/FrontController.php:125]<a href='/4'>#4</a> Piwik_FrontController->dispatch() called at [/var/www/vhost1/gpgtools/www/piwik-1.2/index.php:57]
Screen shot 2011-03-18 at 02.03.26.png
You can see the error message and forum link in the attached screen shot.
Alex, thanks for reporting. I was not able to reproduce upgrading from 1.2 to 1.2.1 I didn't see the error. I assume that the error wasn't causing any other issue? Closing as wont fix for now
Fixed in #2125. The error occurs because the 1.2 version of CoreUpdater_Controller is still loaded in memory when the update occurs.