Account for new psycopg2 exception classes mapping From psycopg2 >= 2.8, specific exceptions are raised corresponding to postgresql errors. E.g. a CheckViolation exception is raised instead of a generic IntegrityError previously when a constraint violation occurs. The way we intercept database errors, especially for constraint violation, is not compliant with that because we do not catch subclasses of IntegrityError in native source's doexec() method. We fix this by checking for the presence of IntegrityError error in exception class's mro. This is still overcomplicated and clumsy, because we still use string comparison, but this is the best we can do as far as I know. (A better fix would be 'isinstance(ex, IntegrityError)' but we have no engine-independent error classes, so this is not possible. Something like sqlalchemy's DBAPI Errors [1] might help: https://docs.sqlalchemy.org/en/latest/errors.html#dbapi-errors)

--- a/cubicweb/server/sources/native.py	Tue Apr 16 15:49:03 2019 +0200
+++ b/cubicweb/server/sources/native.py	Mon Apr 08 11:24:53 2019 +0200
@@ -695,7 +695,8 @@
                         self.debug('transaction has been rolled back')
                 except Exception:
                     pass
-            if ex.__class__.__name__ == 'IntegrityError':
+            if any(cls.__name__ for cls in ex.__class__.__mro__
+                   if cls.__name__ == 'IntegrityError'):
                 # need string comparison because of various backends
                 for arg in ex.args:
                     # postgres, sqlserver