diff -r 4f8aa5fcd5da -r a9940c6cd693 pyramid_cubicweb/core.py
--- a/pyramid_cubicweb/core.py	Wed Apr 29 13:09:06 2015 +0200
+++ b/pyramid_cubicweb/core.py	Fri May 08 11:38:07 2015 +0200
@@ -248,6 +248,8 @@
                 httpexceptions.HTTPSuccessful,
                 httpexceptions.HTTPRedirection))):
             cnx.rollback()
+        elif cnx._cnx.commit_state == 'uncommitable':
+            cnx.rollback()
         else:
             cnx.commit()
         cnx.__exit__(None, None, None)