Unsupported modules now handles the case update module is not installed

If update module is not installed an error message will be shown for the
specific environment. The final message have also changed to prevent
confussions in the output.

scripts/unsupported-modules.php

@@ -6,6 +6,12 @@
 
 use Drupal\update\UpdateManagerInterface;
 
+$module_handler = \Drupal::moduleHandler();
+
+if (!$module_handler->moduleExists('update')) {
+  throw new Exception("Unable to report unsupported modules as Update module is not enabled in the site.");
+}
+
 $updateManager = \Drupal::service('update.manager');
 $updateManager->refreshUpdateData();
 $projectData = $updateManager->getProjects();
@@ -33,7 +39,10 @@
 
 }
 else {
+
   $projects_unsupported_data = [];
 }
 
 print json_encode($projects_unsupported_data);
+
+

src/UpdaterCommand.php

@@ -503,15 +503,21 @@ protected function showObsoleteDrupalModules() {
 
     $unsupported_modules_list = [];
     foreach ($this->environments as $environment) {
-      $unsupported_modules = json_decode(trim($this
-        ->runCommand(sprintf('drush %s php-script %s/../scripts/unsupported-modules.php', $environment, __DIR__))
-        ->getOutput()));
-      foreach ($unsupported_modules as $unsupported_module) {
-        $unsupported_module = (array) $unsupported_module;
-        if (!isset($unsupported_modules_list[$unsupported_module['project_name']])) {
-          $unsupported_modules_list[$unsupported_module['project_name']] = $unsupported_module;
+      try {
+        $unsupported_modules = json_decode(trim($this
+          ->runCommand(sprintf('drush %s php-script %s/../scripts/unsupported-modules.php', $environment, __DIR__))
+          ->getOutput()));
+        foreach ($unsupported_modules as $unsupported_module) {
+          $unsupported_module = (array) $unsupported_module;
+          if (!isset($unsupported_modules_list[$unsupported_module['project_name']])) {
+            $unsupported_modules_list[$unsupported_module['project_name']] = $unsupported_module;
+          }
+          $unsupported_modules_list[$unsupported_module['project_name']]['environments'][] = $environment;
         }
-        $unsupported_modules_list[$unsupported_module['project_name']]['environments'][] = $environment;
+      }
+      catch (ProcessFailedException $exception) {
+        $this->output->writeln('');
+        $this->output->write($exception->getMessage());
       }
     }
 
@@ -534,9 +540,8 @@ protected function showObsoleteDrupalModules() {
       $fixed_drupal_advisories_table->render();
     }
     else {
-      $this->output->writeln('This project does not contain obsolete modules.');
+      $this->output->writeln('No obsolete modules have been found. Perhaps Update module is not installed?');
     }
-
   }
 
   /**