Assuming a plugin contains an invalid update script (e.g. classname, filename or namespace doesn't match), Matomo will currently get stuck in the update process with a message like
The class \Piwik\Plugins\TestPlugin\Updates_0_2_3 was not found in /path/to/matomo/plugins/TestPlugin/Updates/0.2.3.php. There is currently no solution to fix that, besides deactivating the plugin on command line or directly in config.
By throwing an
Error instead of an
Exception, Matomo will show the safemode sceen, that allows deactivating/uninstalling a plugin directly.