add MariaDB placeholder impl

in 599f27dcce62abac1f90a44f9c9a85e7dca885de we updated the
checks for "mariadb" to match SQLAlchemy 1.4.  Another
change if merged will add a new dialect name "mariadb" that's
basically the mysql dialect with a different name; forwards-support
that as well.

Change-Id: I6ba1c13304fa8d6f45dd6453f4c71d04021163ae

diff --git a/alembic/ddl/mysql.py b/alembic/ddl/mysql.py
index 02ce253684a53b9c3d5744ea8ce2a06adf3ba91e..32f04d61e04fbbda8a5fe9eb1dd60a8d3f0e6b87 100644 (file)
--- a/alembic/ddl/mysql.py
+++ b/alembic/ddl/mysql.py
@@ -244,6 +244,10 @@ class MySQLImpl(DefaultImpl):
                 cnfk.onupdate = "RESTRICT"
 
 
+class MariaDBImpl(MySQLImpl):
+    __dialect__ = "mariadb"
+
+
 class MySQLAlterDefault(AlterColumn):
     def __init__(self, name, column_name, default, schema=None):
         super(AlterColumn, self).__init__(name, schema=schema)