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

@@ -11,28 +11,36 @@
 #
 ##############################################################################
 
+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:
-            name, a, b=accept()
-            if name == "Zope2":
-                try:
-                    publish_module(
-                        name,
-                        request=a,
-                        response=b)
-                finally:
-                    b._finish()
-                    a=b=None
+            try:
+                name, a, b=accept()
+                if name == "Zope2":
+                    try:
+                        publish_module(
+                            name,
+                            request=a,
+                            response=b)
+                    finally:
+                        b._finish()
+                        a=b=None
 
-            elif name == "Zope2WSGI":
-                try:
-                    res = publish_wsgi(a, b)
-                    for r in res:
-                        a['wsgi.output'].write(r)
-                finally:
-                    # TODO: Support keeping connections open.
-                    a['wsgi.output']._close = 1
-                    a['wsgi.output'].close()
+                elif name == "Zope2WSGI":
+                    try:
+                        res = publish_wsgi(a, b)
+                        for r in res:
+                            a['wsgi.output'].write(r)
+                    finally:
+                        # TODO: Support keeping connections open.
+                        a['wsgi.output']._close = 1
+                        a['wsgi.output'].close()
+            except:
+                LOG.error('exception caught', exc_info=True)