Fix excessively harsh validation of certain complex configuration

Summary:
See IRC. We're supposed to repair configuration, but if custom validators throw a generic `Exception` or use `PhutilTypeSpec` to do a check, we may explode way harder than we intend to.

Instead, soften these exceptions into validation exceptions so we repair configuration, raise a setup issue, and continue.

Test Plan: {F1059609}

Reviewers: chad

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D14998

src/applications/config/option/PhabricatorApplicationConfigOptions.php

@@ -21,7 +21,14 @@ abstract class PhabricatorApplicationConfigOptions extends Phobject {
     }
 
     if ($option->isCustomType()) {
+      try {
         return $option->getCustomObject()->validateOption($option, $value);
+      } catch (Exception $ex) {
+        // If custom validators threw exceptions, convert them to configuation
+        // validation exceptions so we repair the configuration and raise
+        // an error.
+        throw new PhabricatorConfigValidationException($ex->getMessage());
+      }
     }
 
     switch ($option->getType()) {

src/applications/maniphest/constants/ManiphestTaskPriority.php

@@ -116,7 +116,15 @@ final class ManiphestTaskPriority extends ManiphestConstants {
     return $config;
   }
 
-  public static function validateConfiguration(array $config) {
+  public static function validateConfiguration($config) {
+    if (!is_array($config)) {
+      throw new Exception(
+        pht(
+          'Configuration is not valid. Maniphest priority configurations '.
+          'must be dictionaries.',
+          $config));
+    }
+
     foreach ($config as $key => $value) {
       if (!ctype_digit((string)$key)) {
         throw new Exception(