Taso uncovered a subtle bug where it'll fail to print keyerror exceptions. Fixed, test written, thanks for the report.

AUTHORS

@@ -23,6 +23,7 @@ Linden Lab Contributors
 
 Thanks To
 ---------
+* Taso Du Val, reproing an exception squelching bug, saving children's lives  ;-)
 * R. Tyler Ballance, bug report on tpool on Windows
 * Sergey Shepelev, PEP 8 police  :-)
 * Luci Stanescu, for reporting twisted hub bug

eventlet/hubs/poll.py

@@ -67,10 +67,17 @@ class Hub(BaseHub):
 
         for fileno, event in presult:
             try:
-                if event & READ_MASK:
-                    readers[fileno][0](fileno)
-                if event & WRITE_MASK:
-                    writers[fileno][0](fileno)
+                listener = None
+                try:
+                    if event & READ_MASK:
+                        listener = readers[fileno][0]
+                    if event & WRITE_MASK:
+                        listener = writers[fileno][0]
+                except KeyError:
+                    pass
+                else:
+                    if listener:
+                        listener(fileno)
                 if event & select.POLLNVAL:
                     self.remove_descriptor(fileno)
                     continue
@@ -79,8 +86,6 @@ class Hub(BaseHub):
                                       writers.get(fileno, [])):
                         for listener in listeners:
                             listener(fileno)
-            except KeyError:
-                pass
             except SYSTEM_EXCEPTIONS:
                 raise
             except:

tests/greenio_test.py

@@ -5,6 +5,11 @@ import os
 import socket
 import sys
 
+try:
+    from cStringIO import StringIO
+except ImportError:
+    from StringIO import StringIO
+
 def bufsized(sock, size=1):
     """ Resize both send and receive buffers on a socket.
     Useful for testing trampoline.  Returns the socket.
@@ -212,7 +217,6 @@ class TestGreenIo(LimitedTestCase):
         client.close()
         server_coro.wait()
         listener.close()
-        print len(results1), len(results2)
         self.assert_(len(results1) > 0)
         self.assert_(len(results2) > 0)
         
@@ -225,6 +229,27 @@ class TestGreenIo(LimitedTestCase):
             sock = api.tcp_listener(('127.0.0.1', 0))
             ssl_sock = ssl.wrap_socket(sock)
             
+    def test_exception_squelching(self):
+        server = api.tcp_listener(('0.0.0.0', 0))
+        client = api.connect_tcp(('127.0.0.1', server.getsockname()[1]))
+        client_2, addr = server.accept()
+        
+        def hurl(s):
+            s.recv(1)
+            {}[1]  # keyerror
+
+        fake = StringIO()
+        orig = sys.stderr
+        sys.stderr = fake
+        try:
+            api.spawn(hurl, client_2)            
+            api.sleep(0)
+            client.send(' ')
+            api.sleep(0)
+        finally:
+            sys.stderr = orig
+        self.assert_('Traceback' in fake.getvalue())
+
 
 class SSLTest(LimitedTestCase):
     def setUp(self):