Issue #2176105 by sun: Installer catches exceptions and manually re-prints...

Issue #2176105 by sun: Installer catches exceptions and manually re-prints them; does not use error/exception handler.

core/includes/errors.inc

@@ -116,9 +116,10 @@ function error_displayable($error = NULL) {
  *   TRUE if the error is fatal.
  */
 function _drupal_log_error($error, $fatal = FALSE) {
+  $is_installer = drupal_installation_attempted();
   // Initialize a maintenance theme if the bootstrap was not complete.
   // Do it early because drupal_set_message() triggers a drupal_theme_initialize().
-  if ($fatal && (drupal_get_bootstrap_phase() != DRUPAL_BOOTSTRAP_FULL)) {
+  if (!$is_installer && $fatal && (drupal_get_bootstrap_phase() != DRUPAL_BOOTSTRAP_FULL)) {
     unset($GLOBALS['theme']);
     if (!defined('MAINTENANCE_MODE')) {
       define('MAINTENANCE_MODE', 'error');
@@ -215,14 +216,20 @@ function _drupal_log_error($error, $fatal = FALSE) {
       // We fallback to a maintenance page at this point, because the page generation
       // itself can generate errors.
       // Should not translate the string to avoid errors producing more errors.
-      $output = theme('maintenance_page', array('content' => 'The website has encountered an error. Please try again later.'));
-
-      $response = new Response($output, 500);
-      if ($fatal) {
-        $response->setStatusCode(500, '500 Service unavailable (with message)');
+      $message = 'The website has encountered an error. Please try again later.';
+      if ($is_installer) {
+        // install_display_output() prints the output and ends script execution.
+        install_display_output($message, $GLOBALS['install_state']);
+      }
+      else {
+        $output = theme('maintenance_page', array('content' => $message));
       }
 
-      return $response;
+      $response = new Response($output, 500);
+      $response->setStatusCode(500, '500 Service unavailable (with message)');
+      // An exception must halt script execution.
+      $response->send();
+      exit;
     }
   }
 }

core/includes/install.core.inc

@@ -88,24 +88,14 @@ function install_drupal($settings = array()) {
   // installation.
   $interactive = empty($settings);
   $install_state = $settings + array('interactive' => $interactive) + install_state_defaults();
-  try {
-    // Begin the page request. This adds information about the current state of
-    // the Drupal installation to the passed-in array.
-    install_begin_request($install_state);
-    // Based on the installation state, run the remaining tasks for this page
-    // request, and collect any output.
-    $output = install_run_tasks($install_state);
-  }
-  catch (Exception $e) {
-    // When an installation error occurs, either send the error to the web
-    // browser or pass on the exception so the calling script can use it.
-    if ($install_state['interactive']) {
-      install_display_output($e->getMessage(), $install_state);
-    }
-    else {
-      throw $e;
-    }
-  }
+
+  // Begin the page request. This adds information about the current state of
+  // the Drupal installation to the passed-in array.
+  install_begin_request($install_state);
+  // Based on the installation state, run the remaining tasks for this page
+  // request, and collect any output.
+  $output = install_run_tasks($install_state);
+
   // After execution, all tasks might be complete, in which case
   // $install_state['installation_finished'] is TRUE. In case the last task
   // has been processed, remove the global $install_state, so other code can