Prevent uncaught exceptions from killing ZServer worker threads.

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
+
       - Ensure that mailhosts which share a queue directory do not double-
         deliver mails, by sharing the thread which processes emails for
         that directory.  https://bugs.launchpad.net/zope2/+bug/574286

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)