- Patch #92923 by webchick: made the installer more robust to missing modules.

install.php

@@ -73,8 +73,13 @@ function install_main() {
     install_change_settings($profile, $install_locale);
   }
 
-  // Perform actual installation defined in the profile.
+  // Verify existence of all required modules.
   $modules = drupal_verify_profile($profile, $install_locale);
+  if (!$modules) {
+    install_missing_modules_error($profile);
+  }
+
+  // Perform actual installation defined in the profile.
   drupal_install_profile($profile, $modules);
 
   // Warn about settings.php permissions risk
@@ -498,6 +503,18 @@ function install_already_done_error() {
   exit;
 }
 
+/**
+ * Show an error page when Drupal is missing required modules.
+ */
+function install_missing_modules_error($profile) {
+  global $base_url;
+
+  drupal_maintenance_theme();
+  drupal_set_title(st('Modules missing'));
+  print theme('install_page', '<p>'. st('One or more required modules are missing. Please check the error messages and <a href="!url">try again</a>.', array('!url' => "install.php?profile=$profile")) .'</p>');
+  exit;
+}
+
 /**
  * Page displayed when the installation is complete. Called from install.php.
  */