Make some Herald errors more spider-resistant

Summary:
Fixes T9328. There's no way to hit these error states by clicking things in the UI that I could find, but if you mash stuff into your URL bar or "Inspect Element..." and then edit the form to be full of garbage you can hit them.

Make them a little more informative and don't send them to the log, since these are pretty much just fancy 404s.

Test Plan: Bashed my fist on the URL bar to hit all these messages.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9328

Differential Revision: https://secure.phabricator.com/D14164

src/applications/herald/controller/HeraldRuleController.php

@@ -24,6 +24,8 @@ final class HeraldRuleController extends HeraldController {
       }
       $cancel_uri = $this->getApplicationURI("rule/{$id}/");
     } else {
+      $new_uri = $this->getApplicationURI('new/');
+
       $rule = new HeraldRule();
       $rule->setAuthorPHID($viewer->getPHID());
       $rule->setMustMatchAll(1);
@@ -33,18 +35,40 @@ final class HeraldRuleController extends HeraldController {
 
       $rule_type = $request->getStr('rule_type');
       if (!isset($rule_type_map[$rule_type])) {
-        $rule_type = HeraldRuleTypeConfig::RULE_TYPE_PERSONAL;
+        return $this->newDialog()
+          ->setTitle(pht('Invalid Rule Type'))
+          ->appendParagraph(
+            pht(
+              'The selected rule type ("%s") is not recognized by Herald.',
+              $rule_type))
+          ->addCancelButton($new_uri);
       }
       $rule->setRuleType($rule_type);
 
+      try {
         $adapter = HeraldAdapter::getAdapterForContentType(
           $rule->getContentType());
+      } catch (Exception $ex) {
+        return $this->newDialog()
+          ->setTitle(pht('Invalid Content Type'))
+          ->appendParagraph(
+            pht(
+              'The selected content type ("%s") is not recognized by '.
+              'Herald.',
+              $rule->getContentType()))
+          ->addCancelButton($new_uri);
+      }
 
       if (!$adapter->supportsRuleType($rule->getRuleType())) {
-        throw new Exception(
+        return $this->newDialog()
+          ->setTitle(pht('Rule/Content Mismatch'))
+          ->appendParagraph(
             pht(
-            "This rule's content type does not support the selected rule ".
-            "type."));
+              'The selected rule type ("%s") is not supported by the selected '.
+              'content type ("%s").',
+              $rule->getRuleType(),
+              $rule->getContentType()))
+          ->addCancelButton($new_uri);
       }
 
       if ($rule->isObjectRule()) {