Command "manila-manage db downgrade" without arguments fails

[Igor Malinovskiy]

Command "manila-manage db downgrade" without arguments tries to downgrade db to empty migration, but this is prohibited by base (manila_init) migration:

$ manila-manage db downgrade

2015-01-09 18:37:21.395 DEBUG manila.utils [-] backend <module 'manila.db.migrations.alembic.migration' from '/opt/stack/manila/manila/db/migrations/alembic/migration.pyc'> from (pid=25824) __get_backend /opt/stack/manila/manila/utils.py:184
2015-01-09 18:37:21.416 DEBUG oslo.db.sqlalchemy.session [-] MySQL server mode set to STRICT_TRANS_TABLES,STRICT_ALL_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,TRADITIONAL,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION from (pid=25824) _check_effective_sql_mode /usr/local/lib/python2.7/dist-packages/oslo/db/sqlalchemy/session.py:509
2015-01-09 18:37:21.418 INFO alembic.migration [-] Context impl MySQLImpl.
2015-01-09 18:37:21.418 INFO alembic.migration [-] Will assume non-transactional DDL.
2015-01-09 18:37:21.421 INFO alembic.migration [-] Running downgrade 42c559fa14c5 -> 162a3e673105, add is_deletable field to share_servers table
2015-01-09 18:37:21.537 DEBUG alembic.migration [-] update 42c559fa14c5 to 162a3e673105 from (pid=25824) update_to_step /usr/local/lib/python2.7/dist-packages/alembic/migration.py:493
2015-01-09 18:37:21.546 INFO alembic.migration [-] Running downgrade 162a3e673105 -> , manila_init
2015-01-09 18:37:21.547 CRITICAL manila [-] NotImplementedError: Downgrade from initial Manila install is not supported.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/146807

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/146807
Committed: https://git.openstack.org/cgit/openstack/manila/commit/?id=98faeb138d96157be608b7681ec8c3944c6c46e7
Submitter: Jenkins
Branch: master

commit 98faeb138d96157be608b7681ec8c3944c6c46e7
Author: Igor Malinovskiy <email address hidden>
Date: Tue Jan 20 13:17:50 2015 +0200

    Change default migration in "manila-manage db downgrade" command

    Currently command "manila-manage db downgrade" without arguments
    tries to downgrade db to empty migration, but this is prohibited
    by base (manila_init) migration.

    Set manila_init(162a3e673105) as default migration in downgrade
    command.

    Change-Id: Ia0ccb708a3afa93df68cef6facc4c90b7c088435
    Closes-Bug: #1409770