When an identifier starts with zeroes, treat it as a regexp.

test/DoCommandTest.py

@@ -157,6 +157,14 @@ class DoCommandTest(CommandTest.CommandTest):
         self.assertFalse(self.output)
         self.assertEquals(self.errors, "Invalid todo number given.\n")
 
+    def test_invalid3(self):
+        command = DoCommand(["01"], self.todolist, self.out, self.error, _yes_prompt)
+        command.execute()
+
+        self.assertFalse(self.todolist.is_dirty())
+        self.assertFalse(self.output)
+        self.assertEquals(self.errors, "Invalid todo number given.\n")
+
     def test_activated_todos1(self):
         command = DoCommand(["2"], self.todolist, self.out, self.error)
         command.execute()

topydo/lib/TodoListBase.py

@@ -56,6 +56,13 @@ class TodoListBase(object):
         """
         result = None
         try:
+            try:
+                if not re.match('[1-9]\d*', p_identifier):
+                    raise ValueError # leading zeros, pass to regexp
+            except TypeError:
+                # we're dealing with an integer
+                pass
+
             result = self._todos[int(p_identifier) - 1]
         except IndexError:
             raise InvalidTodoException