Setup check to install/enable pygments

Summary: Fixes T6533 - actively prompt the user to install and enable pygments

Test Plan: uninstalled / disabled pygments and checked setup checks

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T6533

Differential Revision: https://secure.phabricator.com/D11048

src/applications/config/check/PhabricatorSetupCheckPygment.php

@@ -3,7 +3,6 @@
 final class PhabricatorSetupCheckPygment extends PhabricatorSetupCheck {
 
   protected function executeChecks() {
-
     $pygment = PhabricatorEnv::getEnvConfig('pygments.enabled');
 
     if ($pygment) {
@@ -47,6 +46,24 @@ final class PhabricatorSetupCheckPygment extends PhabricatorSetupCheck {
             ->addPhabricatorConfig('environment.append-paths');
         }
       }
+    } else {
+      $summary = pht('Pygments should be installed and enabled '.
+        'to provide advanced syntax highlighting.');
+
+      $message = pht('Phabricator can highlight a few languages by default, '.
+        'but installing and enabling Pygments (a third-party highlighting '.
+        'tool) will add syntax highlighting for many more languages. '."\n\n".
+        'For instructions on installing and enabling Pygments, see the '.
+        '%s configuration option.'."\n\n".
+        'If you do not want to install Pygments, you can ignore this issue.',
+        phutil_tag('tt', array(), 'pygments.enabled'));
+
+      $this
+        ->newIssue('pygments.noenabled')
+        ->setName(pht('Install Pygments to Improve Syntax Highlighting'))
+        ->setSummary($summary)
+        ->setMessage($message)
+        ->addRelatedPhabricatorConfig('pygments.enabled');
     }
   }
 }