[FIX] http dispatch: make sure transaction rollback happens in all cases when request handling raised (to be refactored)

Not doing so leads to cases where a transaction is committed
even after failing to validate a Python constraint.
This patch attempts to keep the rollback() logic next to the
corresponding commit(), and makes the rollback() more
explicit even if close() without commit() would also rollback
implicitly.

bzr revid: odo@openerp.com-20140317163228-zqbce8f0rgcg0pt4

openerp/http.py

@@ -135,6 +135,10 @@ class WebRequest(object):
         self._cr_cm = None
         self._cr = None
         self.func_request_type = None
+
+        # prevents transaction commit, use when you catch an exception during handling
+        self._failed = None
+
         # set db/uid trackers - they're cleaned up at the WSGI
         # dispatching phase in openerp.service.wsgi_server.application
         if self.db:
@@ -178,8 +182,11 @@ class WebRequest(object):
     def __exit__(self, exc_type, exc_value, traceback):
         _request_stack.pop()
         if self._cr:
-            if exc_type is None:
+            if exc_type is None and not self._failed:
                 self._cr.commit()
+            else:
+                # just to be explicit - happens at close() anyway
+                self._cr.rollback()
             self._cr.close()
         # just to be sure no one tries to re-use the request
         self.disable_db = True
@@ -350,6 +357,7 @@ class JsonRequest(WebRequest):
                 'message': "OpenERP Session Invalid",
                 'data': se
             }
+            self._failed = e # prevent tx commit
         except Exception, e:
             _logger.exception("Exception during JSON request handling.")
             se = serialize_exception(e)
@@ -358,6 +366,7 @@ class JsonRequest(WebRequest):
                 'message': "OpenERP Server Error",
                 'data': se
             }
+            self._failed = e # prevent tx commit
         if error:
             response["error"] = error