Fix copying messages to a folder with "empty" name e.g. "0", better error handling

program/steps/mail/copy.inc

@@ -24,7 +24,7 @@ if (!$OUTPUT->ajax_call)
   return;
 
 // move messages
-if (!empty($_POST['_uid']) && !empty($_POST['_target_mbox'])) {
+if (!empty($_POST['_uid']) && strlen($_POST['_target_mbox'])) {
     $uids   = get_input_value('_uid', RCUBE_INPUT_POST);
     $target = get_input_value('_target_mbox', RCUBE_INPUT_POST, true);
     $mbox   = get_input_value('_mbox', RCUBE_INPUT_POST, true);
@@ -47,7 +47,7 @@ if (!empty($_POST['_uid']) && !empty($_POST['_target_mbox'])) {
 }
 // unknown action or missing query param
 else {
-    exit;
+    $OUTPUT->show_message('internalerror', 'error');
 }
 
 // send response

program/steps/mail/mark.inc

@@ -125,9 +125,9 @@ if (($uids = get_input_value('_uid', RCUBE_INPUT_POST)) && ($flag = get_input_va
       }
     }
   }
-
-  $OUTPUT->send();
+}
+else {
+    $OUTPUT->show_message('internalerror', 'error');
 }
 
-exit;
-
+$OUTPUT->send();

program/steps/mail/move_del.inc

@@ -74,6 +74,8 @@ else if ($RCMAIL->action=='delete' && !empty($_POST['_uid'])) {
 }
 // unknown action or missing query param
 else {
+    $OUTPUT->show_message('internalerror', 'error');
+    $OUTPUT->send();
     exit;
 }