Added warning to command when new Grav version is available (#1194)

system/src/Grav/Console/Gpm/UpdateCommand.php

@@ -11,6 +11,7 @@
 use Grav\Common\GPM\GPM;
 use Grav\Common\GPM\Installer;
 use Grav\Console\ConsoleCommand;
+use Grav\Common\GPM\Upgrader;
 use Symfony\Component\Console\Input\ArrayInput;
 use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputOption;
@@ -109,6 +110,22 @@ protected function configure()
      */
     protected function serve()
     {
+        $this->upgrader = new Upgrader($this->input->getOption('force'));
+        $local = $this->upgrader->getLocalVersion();
+        $remote = $this->upgrader->getRemoteVersion();
+        if ($local !== $remote) {
+            $this->output->writeln("<yellow>WARNING</yellow>: A new version of Grav is available. You should update Grav before updating plugins and themes. If you continue without updating Grav, some plugins or themes may stop working.");
+            $this->output->writeln("");
+            $questionHelper = $this->getHelper('question');
+            $question = new ConfirmationQuestion("Continue with the update process? [Y|n] ", true);
+            $answer = $questionHelper->ask($this->input, $this->output, $question);
+
+            if (!$answer) {
+                $this->output->writeln("<red>Update aborted. Exiting...</red>");
+                exit;
+            }
+        }
+
         $this->gpm = new GPM($this->input->getOption('force'));
 
         $this->all_yes = $this->input->getOption('all-yes');