Disallow contentless Ponder answers

Summary:
Any answer without non whitespace characters results in an
error.

Test Plan:
 - Submitted an empty answer, was told off
 - Submitted an answer full of whitespace, didn't like that either
 - Submitted a real answer, accepted

Reviewers: pieter, epriestley, vrana

Reviewed By: epriestley

CC: aran, Korvin, davidreuss

Maniphest Tasks: T1644

Differential Revision: https://secure.phabricator.com/D3492

src/applications/ponder/controller/PonderAnswerSaveController.php

@@ -34,6 +34,17 @@ final class PonderAnswerSaveController extends PonderController {
 
     $answer = $request->getStr('answer');
 
+    // Only want answers with some non whitespace content
+    if (!strlen(trim($answer))) {
+      $dialog = new AphrontDialogView();
+      $dialog->setUser($request->getUser());
+      $dialog->setTitle('Empty answer');
+      $dialog->appendChild('<p>Your answer must not be empty.</p>');
+      $dialog->addCancelButton('/Q'.$question_id);
+
+      return id(new AphrontDialogResponse())->setDialog($dialog);
+    }
+
     $content_source = PhabricatorContentSource::newForSource(
       PhabricatorContentSource::SOURCE_WEB,
       array(
@@ -55,8 +66,7 @@ final class PonderAnswerSaveController extends PonderController {
 
     PhabricatorSearchPonderIndexer::indexQuestion($question);
 
-    return id(new AphrontRedirectResponse())
-      ->setURI(id(new PhutilURI('/Q'. $question->getID()))
-      ->setFragment('A'.$res->getID()));
+    return id(new AphrontRedirectResponse())->setURI(
+      id(new PhutilURI('/Q'. $question->getID())));
   }
 }

src/applications/ponder/view/PonderAddAnswerView.php

@@ -53,6 +53,7 @@ final class PonderAddAnswerView extends AphrontView {
     $form
       ->setUser($this->user)
       ->setAction($this->actionURI)
+      ->setWorkflow(true)
       ->addHiddenInput('question_id', $question->getID())
       ->appendChild(
         id(new AphrontFormTextAreaControl())