Add a friendlier "in flight" error page

Summary:
Ref T11589. When we hit a fatal setup issue (essentially always a connection failure) //after// we've already survived them on at least one request, we can be pretty sure a server went down and that the problem is not a setup/configuration issue.

In this case, show a friendlier error page instead of the fairly detailed technical one.

Test Plan:
- Broke MySQL config.
- Restarted Apache.
- Got the "admin/setup" error page:

{F1803268}

- Fixed the MySQL config.
- Loaded any page, to put us "in flight".
- Broke MySQL config.
- Loaded any page.
- Got the friendly "in flight" error page:

{F1803271}

If you want to design this better, easiest way to get to it is:

- Set `mysql.port` to `9999` in `conf/local/local.json`.
- Reload any page while already running (don't restart).

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11589

Differential Revision: https://secure.phabricator.com/D16503

resources/celerity/map.php

···
     'rsrc/css/application/conduit/conduit-api.css' => '7bc725c4',
     'rsrc/css/application/config/config-options.css' => '0ede4c9b',
     'rsrc/css/application/config/config-page.css' => '8798e14f',
-    'rsrc/css/application/config/config-template.css' => '8e6c6fcd',
+    'rsrc/css/application/config/config-template.css' => '8f18fa41',
     'rsrc/css/application/config/setup-issue.css' => 'f794cfc3',
     'rsrc/css/application/config/unhandled-exception.css' => '4c96257a',
     'rsrc/css/application/conpherence/durable-column.css' => '86396117',
···
     'phabricator-dashboard-css' => 'bc6f2127',
     'phabricator-drag-and-drop-file-upload' => '58dea2fa',
     'phabricator-draggable-list' => '5a13c79f',
-    'phabricator-fatal-config-template-css' => '8e6c6fcd',
+    'phabricator-fatal-config-template-css' => '8f18fa41',
     'phabricator-feed-css' => 'ecd4ec57',
     'phabricator-file-upload' => '680ea2c8',
     'phabricator-filetree-view-css' => 'fccf9f82',

src/__phutil_library_map__.php

···
     'PhabricatorImageMacroRemarkupRule' => 'applications/macro/markup/PhabricatorImageMacroRemarkupRule.php',
     'PhabricatorImageTransformer' => 'applications/files/PhabricatorImageTransformer.php',
     'PhabricatorImagemagickSetupCheck' => 'applications/config/check/PhabricatorImagemagickSetupCheck.php',
+    'PhabricatorInFlightErrorView' => 'applications/config/view/PhabricatorInFlightErrorView.php',
     'PhabricatorIndexEngine' => 'applications/search/index/PhabricatorIndexEngine.php',
     'PhabricatorIndexEngineExtension' => 'applications/search/index/PhabricatorIndexEngineExtension.php',
     'PhabricatorIndexEngineExtensionModule' => 'applications/search/index/PhabricatorIndexEngineExtensionModule.php',
···
     'PhabricatorImageMacroRemarkupRule' => 'PhutilRemarkupRule',
     'PhabricatorImageTransformer' => 'Phobject',
     'PhabricatorImagemagickSetupCheck' => 'PhabricatorSetupCheck',
+    'PhabricatorInFlightErrorView' => 'AphrontView',
     'PhabricatorIndexEngine' => 'Phobject',
     'PhabricatorIndexEngineExtension' => 'Phobject',
     'PhabricatorIndexEngineExtensionModule' => 'PhabricatorConfigModule',

src/applications/config/check/PhabricatorSetupCheck.php

···
     }
   }
 
+  /**
+   * Test if we've survived through setup on at least one normal request
+   * without fataling.
+   *
+   * If we've made it through setup without hitting any fatals, we switch
+   * to render a more friendly error page when encountering issues like
+   * database connection failures. This gives users a smoother experience in
+   * the face of intermittent failures.
+   *
+   * @return bool True if we've made it through setup since the last restart.
+   */
+  final public static function isInFlight() {
+    return (self::getOpenSetupIssueKeys() !== null);
+  }
+
   final public static function loadAllChecks() {
     return id(new PhutilClassMapQuery())
       ->setAncestorClass(__CLASS__)

src/applications/config/response/PhabricatorConfigResponse.php

···
   }
 
   protected function getResponseBodyClass() {
-    return 'setup-fatal';
+    if (PhabricatorSetupCheck::isInFlight()) {
+      return 'setup-fatal in-flight';
+    } else {
+      return 'setup-fatal';
+    }
   }
 
   protected function getResponseBody() {
-    return $this->view->render();
+    $view = $this->view;
+
+    if (PhabricatorSetupCheck::isInFlight()) {
+      return $view->renderInFlight();
+    } else {
+      return $view->render();
+    }
   }
 
   protected function buildPlainTextResponseString() {

src/applications/config/view/PhabricatorInFlightErrorView.php

···
+<?php
+
+final class PhabricatorInFlightErrorView extends AphrontView {
+
+  private $message;
+
+  public function setMessage($message) {
+    $this->message = $message;
+    return $this;
+  }
+
+  public function getMessage() {
+    return $this->message;
+  }
+
+  public function render() {
+    return phutil_tag(
+      'div',
+      array(
+        'class' => 'in-flight-error-detail',
+      ),
+      array(
+        phutil_tag(
+          'h1',
+          array(
+            'class' => 'in-flight-error-title',
+          ),
+          pht('A Troublesome Encounter!')),
+        phutil_tag(
+          'div',
+          array(
+            'class' => 'in-flight-error-body',
+          ),
+          pht(
+            'Woe! This request had its journey cut short by unexpected '.
+            'circumstances (%s).',
+            $this->getMessage())),
+      ));
+  }
+
+}

src/applications/config/view/PhabricatorSetupIssueView.php

···
     return $this->issue;
   }
 
+  public function renderInFlight() {
+    $issue = $this->getIssue();
+
+    return id(new PhabricatorInFlightErrorView())
+      ->setMessage($issue->getName())
+      ->render();
+  }
+
   public function render() {
     $issue = $this->getIssue();
 

webroot/rsrc/css/application/config/config-template.css

···
   text-align: left;
   -webkit-text-size-adjust: none;
 }
+
+body.in-flight {
+  background: #41506e;
+  color: #e0e0e0;
+}
+
+.in-flight-error-detail {
+  max-width: 760px;
+  margin: 72px auto;
+  background: rgba(255, 255, 255, 0.25);
+  border-radius: 3px;
+  padding: 8px 16px;
+}
+
+.in-flight-error-title {
+   padding: 12px 8px;
+   font-size: 24px;
+   font-weight: 500;
+   margin: 0;
+}
+
+.in-flight-error-body {
+   padding: 4px 12px 12px;
+}