From 477d947899332fd303b3b646cac3d62c8e4a6f35 Mon Sep 17 00:00:00 2001
From: Charles Haley <>
Date: Wed, 2 Jun 2010 23:47:54 +0100
Subject: [PATCH] Handle attempts to set tags to the empty string

---
 src/calibre/gui2/dialogs/tag_list_editor.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/calibre/gui2/dialogs/tag_list_editor.py b/src/calibre/gui2/dialogs/tag_list_editor.py
index c2cc1d7116..427e7f44a5 100644
--- a/src/calibre/gui2/dialogs/tag_list_editor.py
+++ b/src/calibre/gui2/dialogs/tag_list_editor.py
@@ -37,6 +37,11 @@ class TagListEditor(QDialog, Ui_TagListEditor):
         self.connect(self.available_tags, SIGNAL('itemChanged(QListWidgetItem *)'), self.finish_editing)
 
     def finish_editing(self, item):
+        if not item.text():
+                error_dialog(self, 'Tag is blank',
+                             'A tag cannot be set to nothing. Delete it instead.'%(item.text())).exec_()
+                item.setText(self.item_before_editing.text())
+                return
         if item.text() != self.item_before_editing.text():
             if item.text() in self.all_tags.keys() or item.text() in self.to_rename.keys():
                 error_dialog(self, 'Tag already used',