Prevent uncaught exceptions from killing ZServer worker threads.

See https://bugs.launchpad.net/zope2/+bug/627988.

doc/CHANGES.txt

@@ -8,6 +8,9 @@ Zope Changes
 
     Bugs fixed
 
+      - Prevent uncaught exceptions from killing ZServer worker threads.
+        https://bugs.launchpad.net/zope2/+bug/627988
+
       - Updated 'pytz' external to point to '2010b' version (not via Zope3).
 
       - Protect ZCTextIndex's clear method against storing Acquisition wrappers.

lib/python/ZServer/PubCore/ZServerPublisher.py

@@ -11,11 +11,17 @@
 #
 ##############################################################################
 
+import logging
+
+LOG = logging.getLogger('ZServerPublisher')
+
 class ZServerPublisher:
     def __init__(self, accept):
+        from sys import exc_info
         from ZPublisher import publish_module
         from ZPublisher.WSGIPublisher import publish_module as publish_wsgi
         while 1:
+            try:
                 name, a, b=accept()
                 if name == "Zope2":
                     try:
@@ -36,3 +42,5 @@ class ZServerPublisher:
                         # TODO: Support keeping connections open.
                         a['wsgi.output']._close = 1
                         a['wsgi.output'].close()
+            except:
+                LOG.error('exception caught', exc_info=True)