Prevent nesting of Misc.tell

Signed-off-by: James McCoy <jamessan@users.sourceforge.net>

plugins/Misc/plugin.py

@@ -381,6 +381,8 @@ class Misc(callbacks.Plugin):
         Tells the <nick> whatever <text> is.  Use nested commands to your
         benefit here.
         """
+        if irc.nested:
+            irc.error('This command cannot be nested.', Raise=True)
         if target.lower() == 'me':
             target = msg.nick
         if ircutils.isChannel(target):

plugins/Misc/test.py

@@ -142,6 +142,9 @@ class MiscTestCase(ChannelPluginTestCase):
         m = self.getMsg('tell me you love me')
         self.failUnless(m.args[0] == self.nick)
 
+    def testNoNestedTell(self):
+        self.assertRegexp('echo [tell %s foo]' % self.nick, 'nested')
+
     def testTellDoesNotPropogateAction(self):
         m = self.getMsg('tell foo [action bar]')
         self.failIf(ircmsgs.isAction(m))