Pass all Throwables to Exception Handlers, not just Exceptions

Summary:
Ref T12855. PHP7 introduced "Throwables", which are sort of like super exceptions. Some errors that PHP raises at runtime have become Throwables instead of old-school errors now.

The major effect this has is blank pages during development under PHP7 for certain classes of errors: they skip all the nice "show a pretty error" handlers and

This isn't a compelete fix, but catches the most common classes of unexpected Throwable and sends them through the normal machinery. Principally, it shows a nice stack trace again instead of a blank page for a larger class of typos and minor mistakes.

Test Plan:
Before: blank page. After:

{F5007979}

Reviewers: chad, amckinley

Reviewed By: chad

Maniphest Tasks: T12855

Differential Revision: https://secure.phabricator.com/D18136

src/aphront/configuration/AphrontApplicationConfiguration.php

@@ -270,7 +270,10 @@ abstract class AphrontApplicationConfiguration extends Phobject {
       }
     } catch (Exception $ex) {
       $original_exception = $ex;
-      $response = $this->handleException($ex);
+      $response = $this->handleThrowable($ex);
+    } catch (Throwable $ex) {
+      $original_exception = $ex;
+      $response = $this->handleThrowable($ex);
     }
 
     try {
@@ -663,24 +666,24 @@ abstract class AphrontApplicationConfiguration extends Phobject {
    * This method delegates exception handling to available subclasses of
    * @{class:AphrontRequestExceptionHandler}.
    *
-   * @param Exception Exception which needs to be handled.
+   * @param Throwable Exception which needs to be handled.
    * @return wild Response or response producer, or null if no available
    *   handler can produce a response.
    * @task exception
    */
-  private function handleException(Exception $ex) {
+  private function handleThrowable($throwable) {
     $handlers = AphrontRequestExceptionHandler::getAllHandlers();
 
     $request = $this->getRequest();
     foreach ($handlers as $handler) {
-      if ($handler->canHandleRequestException($request, $ex)) {
+      if ($handler->canHandleRequestThrowable($request, $throwable)) {
-        $response = $handler->handleRequestException($request, $ex);
+        $response = $handler->handleRequestThrowable($request, $throwable);
         $this->validateErrorHandlerResponse($handler, $response);
         return $response;
       }
     }
 
-    throw $ex;
+    throw $throwable;
   }
 
   private static function newSelfCheckResponse() {

src/aphront/handler/AphrontRequestExceptionHandler.php

@@ -12,19 +12,13 @@ abstract class AphrontRequestExceptionHandler extends Phobject {
 
   abstract public function getRequestExceptionHandlerPriority();
 
-  public function shouldLogException(
+  abstract public function canHandleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable);
-    return null;
-  }
 
-  abstract public function canHandleRequestException(
+  abstract public function handleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex);
+    $throwable);
-
-  abstract public function handleRequestException(
-    AphrontRequest $request,
-    Exception $ex);
 
   final public static function getAllHandlers() {
     return id(new PhutilClassMapQuery())

src/aphront/handler/PhabricatorAjaxRequestExceptionHandler.php

@@ -11,27 +11,28 @@ final class PhabricatorAjaxRequestExceptionHandler
     return pht('Responds to requests made by AJAX clients.');
   }
 
-  public function canHandleRequestException(
+  public function canHandleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
     // For non-workflow requests, return a Ajax response.
     return ($request->isAjax() && !$request->isWorkflow());
   }
 
-  public function handleRequestException(
+  public function handleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
 
     // Log these; they don't get shown on the client and can be difficult
     // to debug.
-    phlog($ex);
+    phlog($throwable);
 
     $response = new AphrontAjaxResponse();
     $response->setError(
       array(
-        'code' => get_class($ex),
+        'code' => get_class($throwable),
-        'info' => $ex->getMessage(),
+        'info' => $throwable->getMessage(),
       ));
+
     return $response;
   }
 

src/aphront/handler/PhabricatorConduitRequestExceptionHandler.php

@@ -11,19 +11,19 @@ final class PhabricatorConduitRequestExceptionHandler
     return pht('Responds to requests made by Conduit clients.');
   }
 
-  public function canHandleRequestException(
+  public function canHandleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
     return $request->isConduit();
   }
 
-  public function handleRequestException(
+  public function handleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
 
     $response = id(new ConduitAPIResponse())
-      ->setErrorCode(get_class($ex))
+      ->setErrorCode(get_class($throwable))
-      ->setErrorInfo($ex->getMessage());
+      ->setErrorInfo($throwable->getMessage());
 
     return id(new AphrontJSONResponse())
       ->setAddJSONShield(false)

src/aphront/handler/PhabricatorDefaultRequestExceptionHandler.php

@@ -11,9 +11,9 @@ final class PhabricatorDefaultRequestExceptionHandler
     return pht('Handles all other exceptions.');
   }
 
-  public function canHandleRequestException(
+  public function canHandleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
 
     if (!$this->isPhabricatorSite($request)) {
       return false;
@@ -22,9 +22,9 @@ final class PhabricatorDefaultRequestExceptionHandler
     return true;
   }
 
-  public function handleRequestException(
+  public function handleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
 
     $viewer = $this->getViewer($request);
 
@@ -33,18 +33,18 @@ final class PhabricatorDefaultRequestExceptionHandler
     // the internet. These include requests with bad CSRF tokens and
     // questionable "Host" headers.
     $should_log = true;
-    if ($ex instanceof AphrontMalformedRequestException) {
+    if ($throwable instanceof AphrontMalformedRequestException) {
-      $should_log = !$ex->getIsUnlogged();
+      $should_log = !$throwable->getIsUnlogged();
     }
 
     if ($should_log) {
-      phlog($ex);
+      phlog($throwable);
     }
 
-    $class = get_class($ex);
+    $class = get_class($throwable);
-    $message = $ex->getMessage();
+    $message = $throwable->getMessage();
 
-    if ($ex instanceof AphrontSchemaQueryException) {
+    if ($throwable instanceof AphrontSchemaQueryException) {
       $message .= "\n\n".pht(
         "NOTE: This usually indicates that the MySQL schema has not been ".
         "properly upgraded. Run '%s' to ensure your schema is up to date.",
@@ -54,7 +54,7 @@ final class PhabricatorDefaultRequestExceptionHandler
     if (PhabricatorEnv::getEnvConfig('phabricator.developer-mode')) {
       $trace = id(new AphrontStackTraceView())
         ->setUser($viewer)
-        ->setTrace($ex->getTrace());
+        ->setTrace($throwable->getTrace());
     } else {
       $trace = null;
     }

src/aphront/handler/PhabricatorHighSecurityRequestExceptionHandler.php

@@ -13,26 +13,26 @@ final class PhabricatorHighSecurityRequestExceptionHandler
       'to present MFA credentials to take an action.');
   }
 
-  public function canHandleRequestException(
+  public function canHandleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
 
     if (!$this->isPhabricatorSite($request)) {
       return false;
     }
 
-    return ($ex instanceof PhabricatorAuthHighSecurityRequiredException);
+    return ($throwable instanceof PhabricatorAuthHighSecurityRequiredException);
   }
 
-  public function handleRequestException(
+  public function handleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
 
     $viewer = $this->getViewer($request);
 
     $form = id(new PhabricatorAuthSessionEngine())->renderHighSecurityForm(
-      $ex->getFactors(),
+      $throwable->getFactors(),
-      $ex->getFactorValidationResults(),
+      $throwable->getFactorValidationResults(),
       $viewer,
       $request);
 
@@ -61,7 +61,7 @@ final class PhabricatorHighSecurityRequestExceptionHandler
           'period of time. When you are finished taking sensitive '.
           'actions, you should leave high security.'))
       ->setSubmitURI($request->getPath())
-      ->addCancelButton($ex->getCancelURI())
+      ->addCancelButton($throwable->getCancelURI())
       ->addSubmitButton(pht('Enter High Security'));
 
     $request_parameters = $request->getPassthroughRequestParameters(

src/aphront/handler/PhabricatorPolicyRequestExceptionHandler.php

@@ -13,20 +13,20 @@ final class PhabricatorPolicyRequestExceptionHandler
       'do something they do not have permission to do.');
   }
 
-  public function canHandleRequestException(
+  public function canHandleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
 
     if (!$this->isPhabricatorSite($request)) {
       return false;
     }
 
-    return ($ex instanceof PhabricatorPolicyException);
+    return ($throwable instanceof PhabricatorPolicyException);
   }
 
-  public function handleRequestException(
+  public function handleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
 
     $viewer = $this->getViewer($request);
 
@@ -52,12 +52,12 @@ final class PhabricatorPolicyRequestExceptionHandler
         array(
           'class' => 'aphront-policy-rejection',
         ),
-        $ex->getRejection()),
+        $throwable->getRejection()),
     );
 
     $list = null;
-    if ($ex->getCapabilityName()) {
+    if ($throwable->getCapabilityName()) {
-      $list = $ex->getMoreInfo();
+      $list = $throwable->getMoreInfo();
       foreach ($list as $key => $item) {
         $list[$key] = $item;
       }
@@ -67,12 +67,14 @@ final class PhabricatorPolicyRequestExceptionHandler
         array(
           'class' => 'aphront-capability-details',
         ),
-        pht('Users with the "%s" capability:', $ex->getCapabilityName()));
+        pht(
+          'Users with the "%s" capability:',
+          $throwable->getCapabilityName()));
 
     }
 
     $dialog = id(new AphrontDialogView())
-      ->setTitle($ex->getTitle())
+      ->setTitle($throwable->getTitle())
       ->setClass('aphront-access-dialog')
       ->setUser($viewer)
       ->appendChild($content);

src/aphront/handler/PhabricatorRateLimitRequestExceptionHandler.php

@@ -13,20 +13,20 @@ final class PhabricatorRateLimitRequestExceptionHandler
       'does something too frequently.');
   }
 
-  public function canHandleRequestException(
+  public function canHandleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
 
     if (!$this->isPhabricatorSite($request)) {
       return false;
     }
 
-    return ($ex instanceof PhabricatorSystemActionRateLimitException);
+    return ($throwable instanceof PhabricatorSystemActionRateLimitException);
   }
 
-  public function handleRequestException(
+  public function handleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
 
     $viewer = $this->getViewer($request);
 
@@ -34,8 +34,8 @@ final class PhabricatorRateLimitRequestExceptionHandler
       ->setTitle(pht('Slow Down!'))
       ->setUser($viewer)
       ->setErrors(array(pht('You are being rate limited.')))
-      ->appendParagraph($ex->getMessage())
+      ->appendParagraph($throwable->getMessage())
-      ->appendParagraph($ex->getRateExplanation())
+      ->appendParagraph($throwable->getRateExplanation())
       ->addCancelButton('/', pht('Okaaaaaaaaaaaaaay...'));
   }
 

src/infrastructure/cluster/exception/PhabricatorClusterExceptionHandler.php

@@ -11,24 +11,24 @@ final class PhabricatorClusterExceptionHandler
     return pht('Handles runtime problems with cluster configuration.');
   }
 
-  public function canHandleRequestException(
+  public function canHandleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
-    return ($ex instanceof PhabricatorClusterException);
+    return ($throwable instanceof PhabricatorClusterException);
   }
 
-  public function handleRequestException(
+  public function handleRequestThrowable(
     AphrontRequest $request,
-    Exception $ex) {
+    $throwable) {
 
     $viewer = $this->getViewer($request);
 
-    $title = $ex->getExceptionTitle();
+    $title = $throwable->getExceptionTitle();
 
     $dialog =  id(new AphrontDialogView())
       ->setTitle($title)
       ->setUser($viewer)
-      ->appendParagraph($ex->getMessage())
+      ->appendParagraph($throwable->getMessage())
       ->addCancelButton('/', pht('Proceed With Caution'));
 
     return id(new AphrontDialogResponse())