backport of the checkin of revision 1.36 of asyncore.py

On Windows, select() does not accept empty lists.
Patch suggested by Guido, fixes SF item 611464.

Bugfix candidate, will backport to release22-maint myself.

diff --git a/Lib/asyncore.py b/Lib/asyncore.py
index 96cc9cc77c2e66c8fb59604f93c3233116e0eb50..bae416b560636ce253431b200fc724bd14241a5c 100644 (file)
--- a/Lib/asyncore.py
+++ b/Lib/asyncore.py
@@ -50,6 +50,7 @@ import exceptions
 import select
 import socket
 import sys
+import time
 
 import os
 from errno import EALREADY, EINPROGRESS, EWOULDBLOCK, ECONNRESET, \
@@ -75,12 +76,15 @@ def poll (timeout=0.0, map=None):
                 r.append (fd)
             if obj.writable():
                 w.append (fd)
-        try:
-            r,w,e = select.select (r,w,e, timeout)
-        except select.error, err:
-            if err[0] != EINTR:
-                raise
-            r = []; w = []; e = []
+        if [] == r == w == e:
+            time.sleep(timeout)
+        else:
+            try:
+                r,w,e = select.select (r,w,e, timeout)
+            except select.error, err:
+                if err[0] != EINTR:
+                    raise
+                r = []; w = []; e = []
 
         if DEBUG:
             print r,w,e