Deprecated: preg_match(): Passing null to parameter #2

[ekubovsky]

Working on the Drupal site, got PHP updated to v8.1. Running Drush commands throws the following error:

Deprecated: preg_match(): Passing null to parameter #2 ($subject) of type string is deprecated in /var/www/vendor/consolidation/site-alias/src/SiteSpecParser.php on line 144

Steps to reproduce

• Install Drupal on PHP8,1.
• Run a Drush command from the root of the project
• Observe error messages in command line

Expected behavior

No errors

Actual behavior

Aforementioned error is displayed

System Configuration

PHP 8.1

[esolitos]

AFAIK This is not happening anymore in the latest version.