Fixes failure when password is null

This patch allows the password column to be null which is the expected
behavior.

Note: We do have tests in place that should have caught this. However,
the SQL model for Password did not explicitly set the nullable column
attribute, so it defaulted to true, even though the migration set it to
false.

Closes-Bug: #1595819

Change-Id: I487072a5b1aeabebd1d2006781fa5dc568160ec5

keystone/common/sql/migrate_repo/versions/106_allow_password_column_to_be_nullable.py

@@ -0,0 +1,21 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import sqlalchemy as sql
+
+
+def upgrade(migrate_engine):
+    meta = sql.MetaData()
+    meta.bind = migrate_engine
+
+    password_table = sql.Table('password', meta, autoload=True)
+    password_table.c.password.alter(nullable=True)

keystone/identity/backends/sql_model.py

@@ -154,7 +154,7 @@ class Password(sql.ModelBase, sql.DictBase):
     id = sql.Column(sql.Integer, primary_key=True)
     local_user_id = sql.Column(sql.Integer, sql.ForeignKey('local_user.id',
                                ondelete='CASCADE'))
-    password = sql.Column(sql.String(128))
+    password = sql.Column(sql.String(128), nullable=True)
     # created_at default set here to safe guard in case it gets missed
     created_at = sql.Column(sql.DateTime, nullable=False,
                             default=datetime.datetime.utcnow)

keystone/tests/unit/test_backend_sql.py

@@ -234,7 +234,7 @@ class SqlIdentity(SqlTests,
         with sql.session_for_read() as session:
             new_user_ref = self.identity_api._get_user(session,
                                                        new_user_dict['id'])
-            self.assertFalse(new_user_ref.password)
+            self.assertIsNone(new_user_ref.password)
 
     def test_update_user_with_null_password(self):
         user_dict = unit.new_user_ref(
@@ -247,7 +247,7 @@ class SqlIdentity(SqlTests,
         with sql.session_for_read() as session:
             new_user_ref = self.identity_api._get_user(session,
                                                        new_user_dict['id'])
-            self.assertFalse(new_user_ref.password)
+            self.assertIsNone(new_user_ref.password)
 
     def test_delete_user_with_project_association(self):
         user = unit.new_user_ref(domain_id=CONF.identity.default_domain_id)

keystone/tests/unit/test_sql_banned_operations.py

@@ -134,7 +134,11 @@ class KeystoneMigrationsCheckers(test_migrations.WalkVersionsMixin):
             # code that referenced the domain table was removed in the Mitaka
             # release, hence this migration will not cause problems when
             # running a mixture of Mitaka and Newton versions of keystone.
-            102
+            102,
+
+            # Migration 106 simply allows the password column to be nullable.
+            # This change would not impact a rolling upgrade.
+            106
         ]
 
         # NOTE(xek): We start requiring things be additive in Newton, so

keystone/tests/unit/test_sql_upgrade.py

@@ -1434,6 +1434,18 @@ class SqlUpgradeTests(SqlMigrateBase):
             session.query(password_table).filter_by(expires_at=None).count())
         self.assertGreater(null_expires_at_cnt, 0)
 
+    def test_migration_106_allow_password_column_to_be_nullable(self):
+        password_table_name = 'password'
+        self.upgrade(105)
+        password_table = sqlalchemy.Table(password_table_name, self.metadata,
+                                          autoload=True)
+        self.assertFalse(password_table.c.password.nullable)
+        self.metadata.clear()
+        self.upgrade(106)
+        password_table = sqlalchemy.Table(password_table_name, self.metadata,
+                                          autoload=True)
+        self.assertTrue(password_table.c.password.nullable)
+
 
 class MySQLOpportunisticUpgradeTestCase(SqlUpgradeTests):
     FIXTURE = test_base.MySQLOpportunisticFixture