If a user creates a session linked to an account, but later deletes that
account using the `litcli accounts remove` command, the KVDB session
will still contain the account ID of the removed account.
During the KVDB to SQL migration, the accounts migration runs before the
sessions migration. Since the deleted account no longer exists, it
cannot be migrated. As a result, the migrated SQL session cannot link to
the now non-existent account in the SQL store.
In such cases, we will migrate the session and not link to any account
in the SQL session.
The logic to avoid duplicate session IDs was first added with the
session linking linking functionality. That means that there may be old
legacy sessions that were added prior to that which may have duplicate
IDs. Before this commit, such sessions would cause the kvdb to SQL
migration to error, as there is a uniqueness constraint on the legacy
session alias in the SQL sessions table.
We want to keep that constraint, so in such rare cases, we update the
kvdb to SQL migration logic to drop all but the session with the
latest CreatedAt time if for sessions that share the same ID.
That follows the logic in c8b78bd10d as
closely as possible, as that migration ensured that all sessions but the
latest one was revoked if multiple sessions shared the same ID.
In the upcoming commit, we will update the kvdb to sql migration to not
always include all sessions in the kvdb store. Therefore, we update the
kvdb to migration tests in order to be able to handle such cases by
including the expected results for each test case.
This commit introduces the migration logic for transitioning the
sessions store from kvdb to SQL.
Note that as of this commit, the migration is not yet triggered by any
production code, i.e. only tests execute the migration logic.
