Deprecated function: preg_split(): Passing null to parameter #2 (mb_strtolower($path)) of type string is deprecated in Drupal\Core\Routing RouteProvider->getRoutesByPath() (line 352 of core/lib/Drupal/Core/Routing/RouteProvider.php)

Thank you for taking an interest

First you shouldn't assign tickets to yourself unless your a maintainer, simple comment should do https://www.drupal.org/docs/develop/issues/issue-procedures-and-etiquett... →

Also this will need steps to reproduce. Need to investigate why this null vs just an isset or empty check. Could be masking a larger problem.

11.x is current development branch

Kindly review the Patch

Build issue fixed patch.

Contributors: please do not ignore comment #4.

Was previously tagged for steps to reproduce and tests.

Also with these kind of issues we need to figure out why that variable is empty vs just putting an issuet() or !empty() check.

Thanks!