Check if Drupal was located before calling realpath

#249

Author: mglaman

Diff for: src/Command/CheckCommand.php

@@ -107,9 +107,10 @@ protected function execute(InputInterface $input, OutputInterface $output): int
             }
         }
 
-        $drupalFinder->locateRoot($drupalRootCandidate);
-        $this->drupalRoot = realpath($drupalFinder->getDrupalRoot());
-        $this->vendorRoot = realpath($drupalFinder->getVendorDir());
+        if ($drupalFinder->locateRoot($drupalRootCandidate)) {
+            $this->drupalRoot = realpath($drupalFinder->getDrupalRoot());
+            $this->vendorRoot = realpath($drupalFinder->getVendorDir());
+        }
 
         if (!$this->drupalRoot) {
             $output->writeln(sprintf('<error>Unable to locate the Drupal root in %s</error>', $drupalRootCandidate));