Overriding the error messages now works for both unique fields, unique_together
and unique_for_date.
This patch changed the overriding logic to allow customizing NON_FIELD_ERRORS
since previously only fields' errors were customizable.
Refs #20199.
Thanks leahculver for the suggestion.
This reverts commit 2ee447fb5f.
That commit introduced a regression (#21882) and didn't really
do what it was supposed to: while it did delay the evaluation
of lazy objects passed to mark_safe(), they weren't actually
marked as such so they could end up being escaped twice.
Refs #21882.
Historically, the Django admin used to pass through the request
from an unauthorized access to the login view directly. Now we
are using a proper redirection, which is also preventing
inadvertantly changing data when POSTing login data to an admin
view when user is already authorized.
Thanks Marc Tamlyn and Tim Graham for the reviews.
This commit touchs various parts of the code base and test framework. Any
found usage of opening a cursor for the sake of initializing a connection
has been replaced with 'ensure_connection()'.
Updated SQLUpdateCompiler.execute_sql to match the behavior described in
the docstring; the 'first non-empty query' will now include all queries,
not just the main and first related update.
Added CURSOR and NO_RESULTS result_type constants to make the usages more
self documenting and allow execute_sql to explicitly close the cursor when
it is no longer needed.
Broke InspectDBTestCase.test_field_types in two:
- a test_number_field_types, which now passes on Oracle too
- a test_field_types, for all non-numeric fields, which is still expected to fail
Also made some pep8 fixes in the tests file. Refs #19884
Thanks Tim Graham for review.
The combination of BaseManager.from_queryset() and RenameMethodsBase results in
Manager.__module__ having the wrong value. This can be an issue when trying to
pickle the Manager class.
Wherever possible this filesystem path is derived automatically from the app
module's ``__path__`` and ``__file__`` attributes (this avoids any
backwards-compatibility problems).
AppConfig allows specifying an app's filesystem location explicitly, which
overrides all autodetection based on ``__path__`` and ``__file__``. This
permits Django to support any type of module as an app (namespace packages,
fake modules, modules loaded by other hypothetical non-filesystem module
loaders), as long as the app is configured with an explicit filesystem path.
Thanks Aymeric for review and discussion.
Also document the conditions under which a namespace package may or may not be
a Django app, and raise a clearer error message in those cases where it may not
be.
Thanks Aymeric for review and consultation.
AppStaticStorage only provided one thing over FileSystemStorage, which was
taking an app name (import path) and translating it into a filesystem
path. This is now something that should be done via app_config.path instead,
leaving AppStaticStorage with no reason for existence. It should be safe to
remove, as it was undocumented internal API.
There was some kind of feature in the AppDirectoriesFinder code related to a
"prefix" attribute on the storage class used by AppDirectoriesFinder. Since
this feature was undocumented, untested, and of unclear purpose, I removed it
as well.
During the admin check for list_editable _check_list_editable_item
should return an empty list if all checks pass. Additionally the
Testcase test_readonly_and_editable was changed to test what the
name implies instead of duplicating the logic of test_readonly.
This is the result of Christopher Medrela's 2013 Summer of Code project.
Thanks also to Preston Holmes, Tim Graham, Anssi Kääriäinen, Florian
Apolloner, and Alex Gaynor for review notes along the way.
Also: Fixes#8579, fixes#3055, fixes#19844.
Allowed users to specify which lookups or transforms ("nested lookus")
are available for fields. The implementation is now class based.
Squashed commit of the following:
commit fa7a7195f1
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Jan 18 10:53:24 2014 +0200
Added lookup registration API docs
commit eb1c8ce164
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Tue Jan 14 18:59:36 2014 +0200
Release notes and other minor docs changes
commit 11501c29c9
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sun Jan 12 20:53:03 2014 +0200
Forgot to add custom_lookups tests in prev commit
commit 83173b960e
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sun Jan 12 19:59:12 2014 +0200
Renamed Extract -> Transform
commit 3b18d9f3a1
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sun Jan 12 19:51:53 2014 +0200
Removed suggestion of temporary lookup registration from docs
commit 21d0c7631c
Merge: 2509006f2dc442
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sun Jan 12 09:38:23 2014 -0800
Merge pull request #2 from mjtamlyn/lookups_3
Reworked custom lookups docs.
commit f2dc4429a1
Author: Marc Tamlyn <marc.tamlyn@gmail.com>
Date: Sun Jan 12 13:15:05 2014 +0000
Reworked custom lookups docs.
Mostly just formatting and rewording, but also replaced the example
using ``YearExtract`` to use an example which is unlikely to ever be
possible directly in the ORM.
commit 2509006506
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sun Jan 12 13:19:13 2014 +0200
Removed unused import
commit 4fba5dfaa0
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Jan 11 22:34:41 2014 +0200
Added docs to index
commit 6d53963f37
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Jan 11 22:10:24 2014 +0200
Dead code removal
commit f9cc039007
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Jan 11 19:00:43 2014 +0200
A new try for docs
commit 33aa18a6e3
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Jan 11 14:57:12 2014 +0200
Renamed get_cols to get_group_by_cols
commit c7d5f8661b
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Jan 11 14:45:53 2014 +0200
Altered query string customization for backends vendors
The new way is trying to call first method 'as_' + connection.vendor.
If that doesn't exist, then call as_sql().
Also altered how lookup registration is done. There is now
RegisterLookupMixin class that is used by Field, Extract and
sql.Aggregate. This allows one to register lookups for extracts and
aggregates in the same way lookup registration is done for fields.
commit 90e7004ec1
Merge: 66649fff7c2c0a
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Jan 11 13:21:01 2014 +0200
Merge branch 'master' into lookups_3
commit 66649ff891
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Jan 11 13:16:01 2014 +0200
Some rewording in docs
commit 31b8faa627
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sun Dec 29 15:52:29 2013 +0200
Cleanup based on review comments
commit 1016159f34
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Dec 28 18:37:04 2013 +0200
Proof-of-concept fix for #16731
Implemented only for SQLite and PostgreSQL, and only for startswith
and istartswith lookups.
commit 193cd097ca
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Dec 28 17:57:58 2013 +0200
Fixed#11722 -- iexact=F() produced invalid SQL
commit 08ed3c3b49
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Dec 21 23:59:52 2013 +0200
Made Lookup and Extract available from django.db.models
commit b99c8d83c9
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Dec 21 23:06:29 2013 +0200
Fixed review notes by Loic
commit 049eebc070
Merge: ed8fab7b80a835
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Dec 21 22:53:10 2013 +0200
Merge branch 'master' into lookups_3
Conflicts:
django/db/models/fields/__init__.py
django/db/models/sql/compiler.py
django/db/models/sql/query.py
tests/null_queries/tests.py
commit ed8fab7fe8
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Dec 21 22:47:23 2013 +0200
Made Extracts aware of full lookup path
commit 27a57b7aed
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sun Dec 1 21:10:11 2013 +0200
Removed debugger import
commit 074e0f5aca
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sun Dec 1 21:02:16 2013 +0200
GIS lookup support added
commit 760e28e72b
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sun Dec 1 20:04:31 2013 +0200
Removed usage of Constraint, used Lookup instead
commit eac4776684
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sun Dec 1 02:22:30 2013 +0200
Minor cleanup of Lookup API
commit 2adf50428d
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sun Dec 1 02:14:19 2013 +0200
Added documentation, polished implementation
commit 32c04357a8
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Nov 30 23:10:15 2013 +0200
Avoid OrderedDict creation on lookup aggregate check
commit 7c8b3a32cc
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Sat Nov 30 23:04:34 2013 +0200
Implemented nested lookups
But there is no support of using lookups outside filtering yet.
commit 4d219d4cde
Author: Anssi Kääriäinen <akaariai@gmail.com>
Date: Wed Nov 27 22:07:30 2013 +0200
Initial implementation of custom lookups
This (nearly) completes the work to isolate all the test modules from
each other. This is now more important as importing models from another
module will case PendingDeprecationWarnings if those modules are not in
INSTALLED_APPS. The only remaining obvious dependencies are:
- d.c.auth depends on d.c.admin (because of the is_admin flag to some
views), but this is not so important and d.c.admin is in
always_installed_apps
- test_client_regress depends on test_client. Eventually these should
become a single module, as the split serves no useful purpose.
When settings.DATABASES['default']['AUTOCOMMIT'] = False, the connection
wasn't in autocommit mode but Django pretended it was.
Thanks Anssi for analysing this issue.
Refs #17062.
Copied attributes into the decorated method and special case __name__
copy as this will not be present on a Class object. Added regression
test to decorator suite.
Originating WSGIRequests are now attached to the ``wsgi_request`` attribute of
the ``HttpResponse`` returned by the testing client.
Thanks rvdrijst for the suggestion.
Make use of `weakref.finalize` and `weakref.WeakMethod` on python 3.4.
Simplified the removal of receivers, the old function looked overly
complicated.
Many thanks go to Antoine Pitrou for helping me to debug and explain all
the failures I ran into while writing that patch.
Models are now attached to any application they're defined in. Since
not_installed was inside app_loading, these models were mistakenly
attached to app_loading. The test that used them passed accidentally
when run after EggLoadingTest because that class' tearDown() method
replaces apps.all_models['app_loading'] by a copy of itself, while
it should remain the same as apps.app_configs['app_loading'].models.
Surprisingly, this commit doesn't change any behavior at all. When a
model is defined with the same name as another model in the same app,
the definition of the first class is bound to the name of the class
regardless of the definition of the second class.
When django.setup() (and then configure_logging) is called inside
catch_warnings, logging setup is negatively affected (notably
warnings.showwarning definition).
When STATIC_ROOT wasn't set, collectstatic --clear would delete
every files within the current directory and its descendants.
This patch makes the following changes:
Prevent collectstatic from running if STATIC_ROOT isn't set.
Fixed an issue that prevented collectstatic from displaying the
destination directory.
Changed the warning header to notify when the command is run
in dry-run mode.
Now that the refactorings are complete, it isn't particularly useful any
more, nor very well named. Let's keep the API as simple as possible.
Fixed#21689.
Since it triggers imports, it shouldn't be done lightly.
This commit adds a public API for doing it explicitly, django.setup(),
and does it automatically when using manage.py and wsgi.py.
Returning None on errors required unpythonic error checking and was
inconsistent with get_app_config.
get_model was a private API until the previous commit, but given that it
was certainly used in third party software, the change is explained in
the release notes.
Applied the same change to get_registered_model, which is a new private
API introduced during the recent refactoring.
ContentTypes are only created for installed applications, and I could
make a case for not returning a model that isn't installed any more.
The check for stale ContentTypes in update_contenttypes doesn't use
model_class.
ModelSignal actually needs get_registered_model since the lookup happens
at import time. I took this opportunity to perform a small refactoring.
This removes the gap between the master app registry and ad-hoc app
registries created by the migration framework, specifically in terms
of behavior of the get_model[s] methods.
This commit contains a stealth feature that I'd rather not describe.
This is to provide a consistent interface (namely bytes) for the smtp
backend which after all sends bytes over the wire; encoding with as_string
yields different results since mails as unicode are not really specified.
as_string stays for backwardscompatibilty mostly and some debug outputs.
But keep in mind that the output doesn't match as_bytes!
The last component of the dotted path to the application module is
consistently referenced as the application "label". For instance it's
AppConfig.label. appname could be confused with AppConfig.name, which is
the full dotted path.
* Introduced [un]set_installed_apps to handle changes to the
INSTALLED_APPS setting.
* Refactored [un]set_available_apps to share its implementation
with [un]set_installed_apps.
* Implemented a receiver to clear some app-related caches.
* Removed test_missing_app as it is basically impossible to reproduce
this situation with public methods of the new app cache.
Currently such overrides aren't reflected in the app cache.
It would be possible to handle them. But that doesn't look like a very
good API. It makes it complicated to express "add this app" and "remove
this app", which are the most common operations on INSTALLED_APPS.
- Tested consistency the current app_configs instead of INSTALLED_APPS.
- Considered applications added with _with_app as available.
- Added docstrings.
Adjusted several tests that used it to add apps to the app cache and
then attempted to remove them by manipulating attributes directly.
Also renamed invalid_models to invalid_models_tests to avoid clashing
application labels between the outer and the inner invalid_models
applications.
It was called _populate() before I renamed it to populate(). Since it
has been superseded by populate_models() there's no reason to keep it.
Removed the can_postpone argument of load_app() as it was only used by
populate(). It's a private API and there's no replacement. Simplified
load_app() accordingly. Then new version behaves exactly like the old
one even though it's much shorter.
First stage imports app modules. It doesn't catch import errors. This
matches the previous behavior and keeps the code simple.
Second stage import models modules. It catches import errors and retries
them after walking through the entire list once. This matches the
previous behavior and seems useful.
populate_models() is intended to be equivalent to populate(). It isn't
wired yet. That is coming in the next commit.
Since applications that aren't installed no longer have an application
configuration, it is now always True in practice.
Provided an abstraction to temporarily add or remove applications as
several tests messed with app_config.installed to achieve this effect.
For now this API is _-prefixed because it looks dangerous.
Got rid of AppConfig._stub. As a side effect, app_cache.app_configs now
only contains entries for applications that are in INSTALLED_APPS, which
is a good thing and will allow dramatic simplifications (which I will
perform in the next commit). That required adjusting all methods that
iterate on app_configs without checking the "installed" flag, hence the
large changes in get_model[s].
Introduced AppCache.all_models to store models:
- while the app cache is being populated and a suitable app config
object to register models isn't available yet;
- for applications that aren't in INSTALLED_APPS since they don't have
an app config any longer.
Replaced get_model(seed_cache=False) by registered_model() which can be
kept simple and safe to call at any time, and removed the seed_cache
argument to get_model[s]. There's no replacement for that private API.
Allowed non-master app caches to go through populate() as it is now
safe to do so. They were introduced in 1.7 so backwards compatibility
isn't a concern as long as the migrations framework keeps working.
* Removed ADMIN_FOR setting and warn warning
* Group view functions by namespace instead of site
* Added a test verifying namespaces are listed
Thanks to Claude Paroz for reviewing and ideas for improvement.
Improved Andrew's hack to create temporary app caches to handle
migrations. Now the main app cache has a "master" flag set to True
(which is a non-default keyword argument, thus unlikely to be used by
mistake). Other app cache instances have "master" set to False.
The only sanctioned way to access the app cache is by importing
django.core.apps.app_cache.
If you were instanciating an app cache and relying on the Borg pattern,
you'll have to refactor your code.
Added comments in the three empty models.py files that are still needed.
Adjusted the test runner to add applications corresponding to test
labels to INSTALLED_APPS even when they don't have a models module.
Several parts of Django call get_apps() with a comment along this lines
of "this has the side effect of calling _populate()". I fail to see how
this is better than just calling populate()!
Refactored get_app() to rely on that method.
get_app() starts by calling _populate(), which goes through
INSTALLED_APPS and, for each app, imports the app module and attempts to
import the models module. At this point, no further imports are
necessary to return the models module for a given app. Therefore, the
implementation of get_app() can be simplified and the safeguards for
race conditions can be removed.
Besides, the emptyOK parameter isn't used anywhere in Django. It was
introduced in d6c95e93 but not actually used nor documented, and it has
just been carried around since then. Since it's an obscure private API,
it's acceptable to stop supporting it without a deprecation path. This
branch aims at providing first-class support for applications without a
models module eventually.
For backwards-compatibility, get_app() still raises ImproperlyConfigured
when an app isn't found, even though LookupError is technically more
correct. I haven't gone as far as to preserve the exact error messages.
I've adjusted a few tests instead.
This commit is a refactoring with no change of functionality, according
to the following invariants:
- An app_label that was in app_configs and app_models stays in
app_config and has its 'installed' attribute set to True.
- An app_label that was in app_models but not in app_configs is added to
app_configs and has its 'installed' attribute set to True.
As a consequence, all the code that iterated on app_configs is modified
to check for the 'installed' attribute. Code that iterated on app_models
is rewritten in terms of app_configs.
Many tests that stored and restored the state of the app cache were
updated.
In the long term, we should reconsider the usefulness of allowing
importing models from non-installed applications. This doesn't sound
particularly useful, can be a trap in some circumstances, and causes
significant complexity in sensitive areas of Django.
Since the original ones in django.db.models.loading were kept only for
backwards compatibility, there's no need to recreate them. However, many
internals of Django still relied on them.
They were also imported in django.db.models. They never appear in the
documentation, except a quick mention of get_models and get_app in the
1.2 release notes to document an edge case in GIS. I don't think that
makes them a public API.
This commit doesn't change the overall amount of global state but
clarifies that it's tied to the app_cache object instead of hiding it
behind half a dozen functions.
All input is now coerced to text before being normalized.
This changes nothing under Python 2 but it allows bytes
to be passed to the function without a TypeError under Python3
(bytes are assumed to be utf-8 encoded text).
Thanks to trac user vajrasky for the report.
Current language is no longer saved to session by LocaleMiddleware
on every response (the behavior introduced in #14825).
Instead language stored in session is reintroduced into new session
after logout.
Forward port of c558a43fd6 to master.
Previously when collecting static files, the directories would receive permissions
from the global umask. Now the default permission comes from FILE_UPLOAD_DIRECTORY_PERMISSIONS
and there's an option to specify the permissions by subclassing any of the
static files storage classes and setting the directory_permissions_mode parameter.
The `remove()` and `clear()` methods of the related managers created by
`ForeignKey`, `GenericForeignKey`, and `ManyToManyField` suffered from a
number of issues. Some operations ran multiple data modifying queries without
wrapping them in a transaction, and some operations didn't respect default
filtering when it was present (i.e. when the default manager on the related
model implemented a custom `get_queryset()`).
Fixing the issues introduced some backward incompatible changes:
- The implementation of `remove()` for `ForeignKey` related managers changed
from a series of `Model.save()` calls to a single `QuerySet.update()` call.
The change means that `pre_save` and `post_save` signals aren't called anymore.
- The `remove()` and `clear()` methods for `GenericForeignKey` related
managers now perform bulk delete so `Model.delete()` isn't called anymore.
- The `remove()` and `clear()` methods for `ManyToManyField` related
managers perform nested queries when filtering is involved, which may
or may not be an issue depending on the database and the data itself.
Refs. #3871, #21174.
Thanks Anssi Kääriäinen and Tim Graham for the reviews.
Updated ModelAdmin to use form.instance when passing parent model to
child inlines for add_view. There is effectively no change in the
change_view since the previously passed 'obj' is the same as form.instance.
Thanks to meshy for report, and EvilDMP and timo for review.
A test for annotations incorrectly assumed that the first instance
(in the test) of a model using AutoField for PK will always get pk=1.
The test was changed to compare against actual instance id instead.
Fixed#20187 -- Allowed repeated iteration of HttpResponse.
All this became possible when support for old-style streaming responses was
finally removed.
Removed multiple locales separated by commas variation (that wasn't
working as documented) in favor of simply allowing use of the
``--locale``/``-l`` options more than once for ``makemessages`` and
``compilemessages``.
Thanks Romain Beylerian for the report and Claude, Simon for their help.
8750296918 from stable/1.6.x.
Thanks Curtis Malony and Florian Apolloner.
Squashed commit of the following:
commit 3380495e93
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date: Sat Nov 23 14:18:07 2013 +0100
Looked up the template_fragments cache at runtime.
commit 905a74f52b
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date: Sat Nov 23 14:19:48 2013 +0100
Removed all uses of create_cache.
Refactored the cache tests significantly.
Made it safe to override the CACHES setting.
commit 35e289fe92
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date: Sat Nov 23 12:23:57 2013 +0100
Removed create_cache function.
commit 8e274f747a
Author: Aymeric Augustin <aymeric.augustin@m4x.org>
Date: Sat Nov 23 12:04:52 2013 +0100
Updated docs to describe a simplified cache backend API.
commit ee7eb0f73e
Author: Curtis Maloney <curtis@tinbrain.net>
Date: Sat Oct 19 09:49:24 2013 +1100
Fixed#21012 -- Thread-local caches, like databases.
Requests made with django.test.Client.login() and logout() respect
defaults defined in django.test.Client instantiation and are processed
through middleware.
Thanks to Loic for the reviews.
This would go unnoticed by the test suite because receivers are removed
automatically when they are garbage collected.
Changed all Signal.connect calls to hold strong references to ensure we
clean up after ourselves.
The GenericRelation refactoring removed GenericRelations from
model._meta.many_to_many. This had the side effect of disallowing
editable GenericRelations in ModelForms. Editable GenericRelations
aren't officially supported, but if we don't fix this we don't offer any
upgrade path for those who used the ability to set editable=True
in GenericRelation subclass.
Thanks to Trac alias joshcartme for the report and stephencmd and Loic
for working on this issue.
Also added some tests for HttpRequest.__repr__.
Note that the added tests don't actually catch the accidental code
removal (see ticket) but they do cover a codepath that wasn't tested
before.
Thanks to Tom Christie for the report and the original patch.
Replaced the custom, untested memoize with a similar decorator from Python's
3.2 stdlib. Although some minor performance degradation (see ticket), it is
expected that in the long run lru_cache will outperform memoize once it is
implemented in C.
Thanks to EvilDMP for the report and Baptiste Mispelon for the idea of
replacing memoize with lru_cache.
``get_template_from_string`` default arguments were breaking
``assertTemplateUsed``. The solution has been to return only the names of the
templates with a ``name`` attribute distinct of ``None``. The default ``name``
kwarg of ``Template`` has been changed to ``None``, more pythonic than ``'<Unknown
Template>'``.
Add the trimmed option to the blocktrans tag to trim any newlines and
whitespace from its content.
This allows the developer to indent the blocktrans tag without adding
new lines and whitespace to the msgid in the PO file.
Thanks to mpessas for the initial patch and Dmitri Fedortchenko for the
report.
Scheme is handled correctly when making comparisons between two URLs. If
there isn't any scheme specified in the location where we are redirected to,
the original request's scheme is used. If present, the scheme in
``expected_url`` is the one used to make the comparations to.
* Safer for use in multiprocess environments
* Better random culling
* Cache files use less disk space
* Safer delete behavior
Also fixed#15806, fixed#15825.
This patch introduces the Prefetch object which allows customizing prefetch
operations.
This enables things like filtering prefetched relations, calling select_related
from a prefetched relation, or prefetching the same relation multiple times
with different querysets.
When a Prefetch instance specifies a to_attr argument, the result is stored
in a list rather than a QuerySet. This has the fortunate consequence of being
significantly faster. The preformance improvement is due to the fact that we
save the costly creation of a QuerySet instance.
Thanks @akaariai for the original patch and @bmispelon and @timgraham
for the reviews.
This commit introduced a new class JoinPromoter that can be used to
abstract away join promotion problems for complex filter conditions.
Query._add_q() and Query.combine() now use the new class.
Also, added a lot of comments about why join promotion is done the way
it is.
Thanks to Tim Graham for original report and testing the changes, and
for Loic Bistuer for review.
Language codes for Chinese are zh_Hans (Simplified) and zh_Hant (Traditional).
Added support for browsers that still send the deprecated language codes.
Thanks to Olli Wang for the report.