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Thomas De Schampheleire

vcs: fix cloning remote repository with HTTP authentication (Issue #379)

Using a remote clone URI of
http://user:pass@host/...
triggered an exception:

...
E File ".../kallithea/lib/utils.py", line 256, in is_valid_repo_uri
E GitRepository._check_url(url)
E File ".../kallithea/lib/vcs/backends/git/repository.py", line 183, in _check_url
E passmgr.add_password(*authinfo)
E File "/usr/lib/python3.7/urllib/request.py", line 848, in add_password
E self.reduce_uri(u, default_port) for u in uri)
E File "/usr/lib/python3.7/urllib/request.py", line 848, in <genexpr>
E self.reduce_uri(u, default_port) for u in uri)
E File "/usr/lib/python3.7/urllib/request.py", line 875, in reduce_uri
E host, port = splitport(authority)
E File "/usr/lib/python3.7/urllib/parse.py", line 1022, in splitport
E match = _portprog.fullmatch(host)
E TypeError: cannot use a string pattern on a bytes-like object

The authinfo tuple is obtained via mercurial.util.url, which unfortunately
returns a tuple of bytes whereas urllib expects strings.
It seems that mercurial internally has some more hacking around urllib as
urllibcompat.py, which we don't use.

Therefore, transform the bytes into strings before passing authinfo to
urllib. As the realm can be None, we need to check it specifically otherwise
safe_str would return a string 'None'.

A basic test that catches the mentioned problem is added, even though it
does not actually test that cloning with auth info will actually work (it
only tests that it fails cleanly if the URI is not reachable).

Additionally, one use of 'test_uri' in hg/repository.py still needed to be
transformed from bytes to string. For git this was already ok.

=======================
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::

    kallithea-cli config-create 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
    kallithea-cli db-create -c temp.ini --repos=/var/repos --user=doe --email doe@example.com --password=123456 --no-public-access --force-yes
    kallithea-cli repo-scan -c 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).