Make sure conflicts are always retried and not masked by exception vi…

…ews (#473)

CHANGES.rst

@@ -14,6 +14,9 @@ https://github.com/zopefoundation/Zope/blob/4.0a6/CHANGES.rst
 Fixes
 +++++
 
+- Make sure conflicts are always retried and not masked by exception views
+  (`#413 <https://github.com/zopefoundation/Zope/issues/413>`_)
+
 - Fix faulty ZMI links due to missing URL-quoting
   (`#391 <https://github.com/zopefoundation/Zope/issues/391>`_)
 

src/ZPublisher/WSGIPublisher.py

@@ -166,6 +166,9 @@ def transaction_pubevents(request, response, tm=transaction.manager):
             notify(pubevents.PubFailure(
                 request, exc_info, request.supports_retry()))
 
+            if isinstance(exc, TransientError) and request.supports_retry():
+                reraise(*exc_info)
+
             if not (exc_view_created or isinstance(exc, Unauthorized)):
                 reraise(*exc_info)
         finally:

src/ZPublisher/tests/test_WSGIPublisher.py

@@ -469,6 +469,50 @@ def _publish(request, module_info):
         finally:
             HTTPRequest.retry_max_count = original_retry_max_count
 
+    def testCustomExceptionViewConflictErrorHandling(self):
+        # Make sure requests are retried as often as configured
+        # even if an exception view has been registered that
+        # matches ConflictError
+        from zope.interface import directlyProvides
+        from zope.publisher.browser import IDefaultBrowserLayer
+        registerExceptionView(Exception)
+        environ = self._makeEnviron()
+        start_response = DummyCallable()
+        _publish = DummyCallable()
+        _publish._raise = ConflictError('oops')
+        _request = DummyRequest()
+        directlyProvides(_request, IDefaultBrowserLayer)
+        _request.response = DummyResponse()
+        _request.retry_count = 0
+        _request.retry_max_count = 3
+        _request.environ = {}
+
+        def _close():
+            pass
+        _request.close = _close
+
+        def _retry():
+            _request.retry_count += 1
+            return _request
+        _request.retry = _retry
+
+        def _supports_retry():
+            return _request.retry_count < _request.retry_max_count
+        _request.supports_retry = _supports_retry
+
+        def _request_factory(stdin, environ, response):
+            return _request
+
+        # At first, retry_count is zero. Request has never been retried.
+        self.assertEqual(_request.retry_count, 0)
+        app_iter = self._callFUT(environ, start_response, _publish,
+                                 _request_factory=_request_factory)
+
+        # In the end the error view is rendered, but the request should
+        # have been retried up to retry_max_count times
+        self.assertTrue(app_iter[1].startswith('Exception View: ConflictError'))
+        self.assertEqual(_request.retry_count, _request.retry_max_count)
+
     def testCustomExceptionViewUnauthorized(self):
         from AccessControl import Unauthorized
         registerExceptionView(IUnauthorized)
@@ -717,6 +761,11 @@ def setBody(self, body):
 
     body = property(lambda self: self._body, setBody)
 
+    def setStatus(self, status, reason=None, lock=None):
+        self._status = status
+
+    status = property(lambda self: self._status, setStatus)
+
 
 class DummyCallable(object):
     _called_with = _raise = _result = None