more: Disallow reading from other users' PM buffers

omnipresence/plugins/more/__init__.py

@@ -6,19 +6,21 @@
 from itertools import tee
 
 from ...message import collapse
-from ...plugin import EventPlugin
+from ...plugin import EventPlugin, UserVisibleError
 from ...settings import PRIVATE_CHANNEL
 
 
 class Default(EventPlugin):
     def on_command(self, msg):
         venue = PRIVATE_CHANNEL if msg.private else msg.venue
         source = msg.content or msg.actor.nick
-        buf = msg.connection.message_buffers[venue].get(source, [])
-        if not buf:
-            return 'No text in buffer.'
+        buf = (msg.connection.message_buffers[venue].get(source, []) or
+               'No text in buffer.')
         if msg.connection.case_mapping.equates(source, msg.actor.nick):
             return buf
+        if msg.private:
+            raise UserVisibleError("You cannot read another user's "
+                                   "private reply buffer.")
         if isinstance(buf, Sequence):
             return buf[:]
         # Assume an iterator.  The original iterator can no longer be

omnipresence/plugins/more/test_more.py

@@ -5,6 +5,7 @@
 from itertools import count, imap
 
 from ...message import Message, collapse
+from ...settings import PRIVATE_CHANNEL
 from ...test.helpers import AbstractCommandTestCase, OutgoingPlugin
 
 from . import Default
@@ -59,3 +60,13 @@ def test_other_buffer_iterator(self):
         self.assert_reply('', '1', actor='party3')
         self.assert_reply('party3', '2')
         self.assert_reply('', '2', actor='party3')
+
+    def test_other_buffer_private(self):
+        private_buffers = self.connection.message_buffers[PRIVATE_CHANNEL]
+        private_buffers[self.other_user.nick] = ['hello world']
+        private_buffers['party3'] = ['lorem ipsum dolor sit amet']
+        self.assert_reply(
+            'party3',
+            "You cannot read another user's private reply buffer.",
+            venue=self.connection.nickname)
+        self.assert_reply('', 'hello world', venue=self.connection.nickname)