Issue #2201615 by hgoto: locale_translate_edit_form_submit() should check is_string(), instead of !empty() for string

modules/locale/locale.admin.inc

@@ -1194,7 +1194,7 @@ function locale_translate_edit_form_submit($form, &$form_state) {
     $translation = db_query("SELECT translation FROM {locales_target} WHERE lid = :lid AND language = :language", array(':lid' => $lid, ':language' => $key))->fetchField();
     if (!empty($value)) {
       // Only update or insert if we have a value to use.
-      if (!empty($translation)) {
+      if (is_string($translation)) {
         db_update('locales_target')
           ->fields(array(
             'translation' => $value,

modules/locale/locale.test

@@ -393,6 +393,16 @@ class LocaleTranslationFunctionalTest extends DrupalWebTestCase {
     // The indicator should not be here.
     $this->assertNoRaw($language_indicator, 'String is translated.');
 
+    // Verify that a translation set which has an empty target string can be
+    // updated without any database error.
+    db_update('locales_target')
+      ->fields(array('translation' => ''))
+      ->condition('language', $langcode, '=')
+      ->condition('lid', $lid, '=')
+      ->execute();
+    $this->drupalPost('admin/config/regional/translate/edit/' . $lid, $edit, t('Save translations'));
+    $this->assertText(t('The string has been saved.'), 'The string has been saved.');
+
     // Try to edit a non-existent string and ensure we're redirected correctly.
     // Assuming we don't have 999,999 strings already.
     $random_lid = 999999;