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Søren Løvborg
auth: add AuthUser.is_anonymous, along with some exposition

This reveals the name of the NotAnonymous decorator to be misleading,
an unfortunate detail only documented here, but which must be properly
resolved in a later changeset.

Note that NotAnonymous behaves as advertised as long as it is used
together with LoginRequired, which is always the case in the current
code, so there's no actual security issue here, the code is just weird,
hard to read and fragile.

---

Some thoughts on cleaning this up in a future changeset: As it turns
out, every controller (except the login page!) should be LoginRequired
decorated (since it doesn't actually block anonymous users, as long as
anonymous access is enabled in the Kallithea config). Thus the most
obvious solution would be to move the LoginRequired functionality into
BaseController (with an override for LoginController), and delete the
decorator entirely. However, LoginRequired does one other thing: it
carries information about whether API access is enabled for individual
controller methods ("@LoginRequired(api_key=True)"), and also performs
the check for this, something which is not easily moved into the base
controller class, since the base controller doesn't know which method is
about to be called. Possibly that can be determined by poking Pylons,
but such code is likely to break with the upcoming TurboGears 2 move.
Thus such cleanup is probably better revisited after the switch to TG2.
=======================
Database schema changes
=======================

Kallithea uses Alembic for :ref:`database migrations <upgrade_db>`
(upgrades and downgrades).

If you are developing a Kallithea feature that requires database schema
changes, you should make a matching Alembic database migration script:

1. :ref:`Create a Kallithea configuration and database <setup>` for testing
   the migration script, or use existing ``development.ini`` setup.

   Ensure that this database is up to date with the latest database
   schema *before* the changes you're currently developing. (Do not
   create the database while your new schema changes are applied.)

2. Create a separate throwaway configuration for iterating on the actual
   database changes::

    paster make-config Kallithea temp.ini

   Edit the file to change database settings. SQLite is typically fine,
   but make sure to change the path to e.g. ``temp.db``, to avoid
   clobbering any existing database file.

3. Make your code changes (including database schema changes in ``db.py``).

4. After every database schema change, recreate the throwaway database
   to test the changes::

    rm temp.db
    paster setup-db temp.ini --repos=/var/repos --user=doe --email doe@example.com --password=123456 --no-public-access --force-yes
    paster repo-scan temp.ini

5. Once satisfied with the schema changes, auto-generate a draft Alembic
   script using the development database that has *not* been upgraded.
   (The generated script will upgrade the database to match the code.)

   ::

    alembic -c development.ini revision -m "area: add cool feature" --autogenerate

6. Edit the script to clean it up and fix any problems.

   Note that for changes that simply add columns, it may be appropriate
   to not remove them in the downgrade script (and instead do nothing),
   to avoid the loss of data. Unknown columns will simply be ignored by
   Kallithea versions predating your changes.

7. Run ``alembic -c development.ini upgrade head`` to apply changes to
   the (non-throwaway) database, and test the upgrade script. Also test
   downgrades.

   The included ``development.ini`` has full SQL logging enabled. If
   you're using another configuration file, you may want to enable it
   by setting ``level = DEBUG`` in section ``[handler_console_sql]``.

The Alembic migration script should be committed in the same revision as
the database schema (``db.py``) changes.

See the `Alembic documentation`__ for more information, in particular
the tutorial and the section about auto-generating migration scripts.

.. __: http://alembic.zzzcomputing.com/en/latest/


Troubleshooting
---------------

* If ``alembic --autogenerate`` responds "Target database is not up to
  date", you need to either first use Alembic to upgrade the database
  to the most recent version (before your changes), or recreate the
  database from scratch (without your schema changes applied).