Improve error messages for PHABRICATOR_ENV

Summary:
- Allow user to specify "myconf" (recommended) or "myconf.conf.php" (less
surprising).
  - Make sure syntax errors and other problems are surfaced.
  - If the configuration value isn't valid, give them a list of all valid
values.

Test Plan:
- Added a syntax error, got a useful error.
  - Set PHABRICATOR_ENV to a silly value, got a list of valid values.
  - Set PHABRICATOR_ENV to have .conf.php suffix, site still worked.

Reviewed By: kevinwallace
Reviewers: kevinwallace, codeblock, aran, jungejason, tuomaspelkonen
CC: aran, epriestley, kevinwallace
Differential Revision: 381

conf/__init_conf__.php

@@ -16,11 +16,47 @@
  * limitations under the License.
  */
 
-function phabricator_read_config_file($config) {
+function phabricator_read_config_file($original_config) {
+
   $root = dirname(dirname(__FILE__));
-  $conf = include $root.'/conf/'.$config.'.conf.php';
+
+  // Accept either "myconfig" (preferred) or "myconfig.conf.php".
+  $config = preg_replace('/\.conf\.php$/', '', $original_config);
+  $full_config_path = $root.'/conf/'.$config.'.conf.php';
+
+  // Make sure config file errors are reported.
+  $old_error_level = error_reporting(E_ALL | E_STRICT);
+  $old_display_errors = ini_get('display_errors');
+  ini_set('display_errors', 1);
+
+    ob_start();
+    $conf = include $full_config_path;
+    $errors = ob_get_clean();
+
+  error_reporting($old_error_level);
+  ini_set('display_errors', $old_display_errors);
+
   if ($conf === false) {
-    throw new Exception("Failed to read config file '{$config}'.");
+    if (!Filesystem::pathExists($full_config_path)) {
+      $files = id(new FileFinder($root.'/conf/'))
+        ->withType('f')
+        ->withSuffix('conf.php')
+        ->withFollowSymlinks(true)
+        ->find();
+
+      foreach ($files as $key => $file) {
+        $file = trim($file, './');
+        $files[$key] = preg_replace('/\.conf\.php$/', '', $file);
+      }
+      $files = "    ".implode("\n    ", $files);
+
+      throw new Exception(
+        "CONFIGURATION ERROR\n".
+        "Config file '{$original_config}' does not exist. Valid config files ".
+        "are:\n\n".$files);
+    }
+    throw new Exception("Failed to read config file '{$config}': {$errors}");
   }
+
   return $conf;
 }

webroot/index.php

@@ -55,11 +55,11 @@ if (get_magic_quotes_gpc()) {
 require_once dirname(dirname(__FILE__)).'/conf/__init_conf__.php';
 
 try {
+  setup_aphront_basics();
+
   $conf = phabricator_read_config_file($env);
   $conf['phabricator.env'] = $env;
 
-  setup_aphront_basics();
-
   phutil_require_module('phabricator', 'infrastructure/env');
   PhabricatorEnv::setEnvConfig($conf);