From: Tim Peters <tim.peters@gmail.com>
Date: Sun, 8 Apr 2001 07:23:44 +0000 (+0000)
Subject: Fix from the Madusa mailing list:
X-Git-Tag: v2.1c1~163
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=6fd71206169c48daf9a45fe246b495bb8113fd10;p=thirdparty%2FPython%2Fcpython.git

Fix from the Madusa mailing list:
    http://groups.yahoo.com/group/medusa/message/333

It's clear that Medusa should not be checking for an empty buffer
via "buf is ''".  The patch merely changes "is" to "==".  However,
there's a mystery here all the same:  Python attempts to store null
strings uniquely, so it's unclear why "buf is ''" ever returned
false when buf actually was empty.  *Some* string operations produce
non-unique null strings, e.g.

>>> "abc"*0 is "abc"*0
0
>>>

but they're rare, and I don't see any such operations in asynchat.
---

diff --git a/Lib/asynchat.py b/Lib/asynchat.py
index 584aab9f3eb0..1f9fc6839be6 100644
--- a/Lib/asynchat.py
+++ b/Lib/asynchat.py
@@ -165,7 +165,7 @@ class async_chat (asyncore.dispatcher):
         # return len(self.ac_out_buffer) or len(self.producer_fifo) or (not self.connected)
         # this is about twice as fast, though not as clear.
         return not (
-                (self.ac_out_buffer is '') and
+                (self.ac_out_buffer == '') and
                 self.producer_fifo.is_empty() and
                 self.connected
                 )