tests: always pass username as cur_user

Passing a whole User wouldn't work if actually using celery and thus
serializing the parameters. The test scenario was thus different from actual
runtime.

db: move URL_SEP constant from db to top level kallithea module

URL_SEP is used in several places - having it in the db module is too high
level.

__init__ might not be the best place for this, but it does no harm to the
dependencies graph to place constants there.

auth: refactor permissions

Avoid using complex vague typing in dict-of-dicts.

permissions: drop hg.create.write_on_repogroup "Repository creation with group write access" setting

Simplify permissions system and get rid of some confusing tech debt.

Before, the global 'write_on_repogroup' setting controlled what write
permission on a repo group meant.

With this change, users can create repositories in a repo group if and only if
they have write access. Write access to a repo group will now mean the
permission to create repositories in it.

Write access to repo groups must be granted explicitly. There should not be any
other reason to grant write access than to allow users to create repos. There
is thus no upgrade concerns for this change.

An admin that doesn't want users to create repos in a repogroup should just not
give them write access.

These global settings might still exist in the database, but is ignored and no
longer used and do no harm.

tests: fix TestPermissions.test_inactive_user_group_does_not_affect_repo_group_permissions_inverse

Handle L1_new leak from test_rename_top_level_group_in_nested_setup .

cleanup: get rid of most "import *"

Apply script generated with the following hack:
(
hg loc '*.py'|xargs pyflakes-2 | sed -rn "s/([^:]*):.*'(.*)' may be undefined, or defined from star imports.*/sed -ri 's,\\\\<\2\\\\>([^=]|$),XXXX.\2\\\\1,g' \1/gp" | sort -u
hg loc '*.py'|xargs pyflakes-2 | sed -rn "s/([^:]*):.* undefined name '(.*)'$/sed -ri 's,\\\\<\2\\\\>([^=]|$),XXXX.\2\\\\1,g' \1/gp" | sort -u
hg loc '*.py'|xargs pyflakes-2 | sed -rn "s/([^:]*):.*'(from .*)\.([^.]*) import \*' used.*/sed -ri 's,\\\\<XXXX\\\\.,\3.,g' \1/gp" | sort -u
hg loc '*.py'|xargs pyflakes-2 | sed -rn "s/([^:]*):.*'(from .*)\.([^.]*) import \*' used.*/sed -ri 's,\2\\\\.\3 .*,\2 import \3,g' \1/gp" | sort -u
) | grep -v kallithea/bin/kallithea_cli_ishell.py > fix2.sh

auth: drop "multiple_counter" from computing permissions

This seems to have been something about having some permissions override
existing permissions. It is not clear to me why anybody should want that.

test_user_group_permissions_on_repo_groups.py seems to have been testing for
something we don't want. The new behaviour seems more reasonable. The test user
is inhering access from the default user, and thus in this case getting read
access (except when private).

auth: minor refactoring of computation of admin access for repo owners

Make the flow slightly simpler ... and now when permissions are merged, we only
have to set repo owner access once.

BUT: because multiple_counter, we actually don't merge permissions in all
cases. This will thus introduce a regression that will be fixed in next
changeset.

auth: explicit user permission should not blindly overrule permissions through user groups

Before, explicit permissions of a user could shadow higher permissions that
would otherwise be obtained through a group the user is member of.
That was confusing and fragile: *removing* a permission could then suddenly
give a user *more* permissions.

Instead, change the flag for controlling internal permission computation to
*not* use "explicit". Permissions will then add up, no matter if they are
explicit or through groups.

The change in auth.py is small, but read the body of __get_perms to see the
actual impact ... and also the clean-up changeset that will come next.

This might in some cases be a behaviour change and give users more access ...
but it will probably only give the user that was intended. This change can thus
be seen as a bugfix.

Some tests assumed the old behaviour. Not for good reasons, but just because
that is how they were written. These tests are updated to expect the new
behaviour, and it has been reviewed that it makes sense.

Note that this 'explicit' flag mostly is for repo permissions and independent
of the 'user_inherit_default_permissions' that just was removed and is about
global permissions.

auth: global permissions given to the default user are the bare minimum and should apply to *all* other users too

Drop the "subtractive permission" config option "inherit_from_default" that
when set to false would give users less global permissions than the default
unauthenticated user.

Instead, think positive and merge all positive permissions.

At the end, filter the global permissions to make sure we for each kind of
permissions only keep the one with most weight.

codingstyle: replace comparison for equality against None with "is" expression

Both style and correctness.

Reported by flake8.

codingstyle: trivial whitespace fixes

Reported by flake8.

sqlalchemy: fix warnings from running the test suite

Mainly warnings about strings being passed where unicode was expected.

db: remove superfluous Session.add calls

Don't re-add objects to the SQLAlchemy Session just because they were
modified. Session.add is only for freshly constructed objects that
SQLAlchemy doesn't know about yet.

The rules are quite simple:

When creating a database object by calling the constructor directly, it
must explicitly be added to the session.

When creating an object using a factory function (like "create_repo"),
the returned object has already (by convention) been added to the
session, and should not be added again.

When getting an object from the session (via Session.query or any of the
utility functions that look up objects in the database), it's already
added, and should not be added again. SQLAlchemy notices attribute
modifications automatically for all objects it knows about.

tests: add as little code as possible in __init__.py

kallithea/tests/__init__.py contained quite a lot of code, including the test
base class TestController. This in itself may be considered bad practice.

Specifically, this poses a problem when using pytest 3.0+, in which asserts
in some files are not automatically rewritten to give improved assert
output. That problem can be fixed by explicitly registering such files for
assertion rewriting, but that register call should be executed _before_ said
files are imported. I.e. if the register call is in
kallithea/tests/__init__.py, assert calls in __init__.py itself can not be
rewritten.

Since the TestController base class does effectively contain asserts, and we
do not want to execute the register call from somewhere outside the
kallithea/tests directory, we need to move the TestController class to
another file (kallithea/tests/base.py) so we can have a register call in
__init__.py before loading base.py.

While not strictly necessary to fix the mentioned pytest problem, we take
the opportunity to fully clean __init__.py and move everything to
the new kallithea/tests/base.py. While doing so, unnecessary imports are
removed, and imports are ordered alphabetically. Explicit imports of symbols
from modules that were already imported as a whole, are removed in favor of
fully qualifying the references (e.g. tempfile._RandomNameSequence).

pytest migration: rename TestControllerPytest back to TestController

The name TestControllerPytest was introduced to allow a temporary situation
where nose/unittest and pytest-based tests could coexist.
This situation is now over, so the base test class can be renamed again.

pytest migration: models: switch to standard assert statements

Use unittest2pytest to replace unittest-style assert statements (e.g.
assertEqual) with standard Python assert statements to benefit from pytest's
improved reporting on assert failures.

The conversion by unittest2pytest was correct except for:
- 'import pytest' is not automatically added when needed
- line wrapping in string formatting caused a syntax error in the
transformed code. Reported upstream at
https://github.com/pytest-dev/unittest2pytest/issues/3 .
- in assertRaises with a lambda, the lambda needs to be removed

pytest migration: model: convert all tests to TestControllerPytest

The model tests were based on BaseTestCase which does not exist currently
for pytest-style tests. Nevertheless, there seems to be no advantage of
directly subclassing BaseTestCase over subclassing TestControllerPytest.
Thus, keep things simple and use TestControllerPytest.

tests: more consistently use unicode where unicode is expected

Nothing but extra u annotation to turn str constants into unicode.

This has been verified by hacking sqlalchemy to fail if wrong string types are passed.

auth: ignore permissions from in-active user groups (Issue #138)

Tests by Thomas De Schampheleire.

Additionally, rename the unused and seemingly search-replace-massacred
function revokehas_permrevoke_permgrant_perm_perm into revoke_perm.

Second step in two-part process to rename directories.
This is the actual directory rename.