Object of class Drupal\user\Entity\User could not be converted to string

During corn execution if by mistake from '/admin/config/content/linkchecker', somebody set an user under 'Error handling / Impersonate user account' that later for whatever reason, is deleted and the setting is not updated, the hook_cron throws this error because try to load an inexistent user.

I have updated the patch, in case that the value of the variable after the user_load is empty, then load the superadmin to avoid Fatal errors during the execution and allow the normal execution of Drupal Cron.

I created this issue but i think that now is irrelevant:
https://www.drupal.org/project/linkchecker/issues/3422365 🐛 Cron Execution issue - Error: Call to a member function id() on bool in Drupal\linkchecker\Plugin\LinkStatusHandlerBase->switchSession() Active

Sorry the last one #12 had invalid end line.

I did reproduce the issue on the 2.0.x release as well.

To summarize steps from #10 - this error is reproducible if any status handler plugin is enabled. It happens here - \Drupal\linkchecker\Plugin\LinkStatusHandlerBase::switchSession because the user object is passed instead of the user ID.

I do believe it should be detected and tested in LinkcheckerRepair301Test and LinkcheckerUnpublish404Test but for some reason, tests are passing... I'll try to investigate it and fix

Ok, so I found a place where the error happens: module system, \Drupal\system\TimeZoneResolver::getTimeZone.

Since here we're setting the user object as uid (idk why) - \Drupal\linkchecker\Plugin\LinkStatusHandlerBase::switchSession ->

$this->uid > 0

check in \Drupal\Core\Session\UserSession::isAuthenticated method leads to the error (called in TimeZoneResolver event subscriber)

More details in the attached screenshot

I guess it could be reviewed now.

P.S. in LinkcheckerUnpublish404Test and LinkcheckerRepair301Test I have added the 'system' module in $this->installConfig so that system configs will be installed and the check

$this->currentUser->isAuthenticated()

will be called here: \Drupal\system\TimeZoneResolver::getTimeZone

  protected function getTimeZone() {
    $config = $this->configFactory->get('system.date');
    if ($config->get('timezone.user.configurable') && $this->currentUser->isAuthenticated() && $this->currentUser->getTimezone()) {
      return $this->currentUser->getTimeZone();
    }
    elseif ($default_timezone = $config->get('timezone.default')) {
      return $default_timezone;
    }
    return NULL;
  }

The last submitted patch, 7: object_of_class_user_could_not_be_converted_to_string-3247797-7.patch, failed testing. View results →