Index: modules/locale/locale.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/locale/locale.module,v
retrieving revision 1.258
diff -u -p -r1.258 locale.module
--- modules/locale/locale.module	31 Aug 2009 17:06:09 -0000	1.258
+++ modules/locale/locale.module	5 Sep 2009 14:47:18 -0000
@@ -681,3 +681,30 @@ function theme_locale_translation_filter
   $output .= '<div id="locale-translation-buttons">' . drupal_render($form['buttons']) . '</div>';
   return $output;
 }
+
+/**
+ * Implement hook_requirements().
+ */
+function locale_requirements($phase) {
+  $requirements = array();
+  // Ensure translations don't break at install time
+  $t = get_t();
+
+  $mode = variable_get('language_negotiation', LANGUAGE_NEGOTIATION_NONE);
+
+  // Count languages on the system
+  $languages = language_list('language');
+  $language_count = 0;
+  foreach ($languages as $langcode => $language) {
+    $language_count += count($language);	
+  }
+
+  if ($language_count > 1 && $mode == LANGUAGE_NEGOTIATION_NONE) {	
+    $requirements['locale'] = array(
+      'title' => $t('Locale'),
+      'value' => $t('You have more than one language enabled but no language negotiation set up.'. ' ' . l(t('Configure language negotiation'), 'admin/config/regional/language/configure')),
+      'severity' => REQUIREMENT_WARNING,
+    );  
+  }
+  return $requirements;
+}
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