Adapt to SQLAlchemy 1.4

This patch makes the necessary change to adapt to the SQLAlchemy 1.4
release in a way that is still compatible with the currently pinned 1.3
versions.

This is related to the overall effort to bump SQLAlchemy to 1.4
https://review.opendev.org/c/openstack/requirements/+/788339

Co-Authored-By: Mike Bayer <[email protected]>

Closes-Bug: #1926426
Change-Id: I8a0ab3b91b4203ab603caac02ee5132be7890e9a

Author: Balazs Gibizer

nova/cmd/manage.py

@@ -706,7 +706,16 @@ def cell0_default_connection():
             # worry about parsing and splitting a URL which could have special
             # characters in the password, which makes parsing a nightmare.
             url = sqla_url.make_url(connection)
-            url.database = url.database + '_cell0'
+
+            # TODO(gibi): remove hasattr() conditional in favor of "url.set()"
+            # when SQLAlchemy 1.4 is the minimum version in requirements
+            if hasattr(url, "set"):
+                url = url.set(database=url.database + '_cell0')
+            else:
+                # TODO(zzzeek): remove when SQLAlchemy 1.4
+                # is the minimum version in requirements
+                url.database = url.database + '_cell0'
+
             return urlparse.unquote(str(url))
 
         dbc = database_connection or cell0_default_connection()