Don't call rollback on DBAPI connection that's "closed"

Use the existence of ConnectionRecord.connection to estimate
that this connection is likely closed, and if so, don't
try to call "rollback" on it.  This rollback is normally harmless
but is causing segfaults in mysqlclient due to
https://github.com/PyMySQL/mysqlclient-python/issues/270.

Change-Id: I1d7c5f5a520527d8268b6334795c2051f7ceeea6
(cherry picked from commit a8781b51b4039eee56791b9dbfdee183f7a5b797)

diff --git a/lib/sqlalchemy/testing/engines.py b/lib/sqlalchemy/testing/engines.py
index f452a3e2f68e8f47c4e5fab4459f19b46aec539a..f963ba8b25339067762a5255bd6a28b5f96f5240 100644 (file)
--- a/lib/sqlalchemy/testing/engines.py
+++ b/lib/sqlalchemy/testing/engines.py
@@ -59,6 +59,12 @@ class ConnectionKiller(object):
         # not sure if this should be if pypy/jython only.
         # note that firebird/fdb definitely needs this though
         for conn, rec in list(self.conns):
+            if rec.connection is None:
+                # this is a hint that the connection is closed, which
+                # is causing segfaults on mysqlclient due to
+                # https://github.com/PyMySQL/mysqlclient-python/issues/270;
+                # try to work around here
+                continue
             self._safe(conn.rollback)
 
     def _stop_test_ctx(self):