When Django reraises an exception, it sets the __cause__ attribute even
in Python 2, mimicking Python's 3 behavior for "raise Foo from Bar".
However, Python 3 also ensures that all exceptions have a __traceback__
attribute and thus the "traceback2" Python 2 module (backport of Python
3's "traceback" module) relies on the fact that whenever you have a
__cause__ attribute, the recorded exception also has a __traceback__
attribute.
This is breaking testtools which is using traceback2 (see
https://github.com/testing-cabal/testtools/issues/162).
This commit fixes this inconsistency by ensuring that Django sets
the __traceback__ attribute on any exception stored in a __cause__
attribute of a reraised exception.
The primary use case is to interact with a third-party database (not
primarily managed by Django) that doesn't support time zones and where
datetimes are stored in local time when USE_TZ is True.
Configuring a PostgreSQL database with the TIME_ZONE option while USE_TZ
is False used to result in silent data corruption. Now this is an error.
The new signature enables better support for routing RunPython and
RunSQL operations, especially w.r.t. reusable and third-party apps.
This commit also takes advantage of the deprecation cycle for the old
signature to remove the backward incompatibility introduced in #22583;
RunPython and RunSQL won't call allow_migrate() when when the router
has the old signature.
Thanks Aymeric Augustin and Tim Graham for helping shape up the patch.
Refs 22583.
This allows specifying ForeignKeys in REQUIRED_FIELDS when using a
custom User model.
Thanks cjerdonek and bmispelon for suggestion and timgraham for review.
Change database test settings from "TEST_"-prefixed entries in the
database settings dictionary to setting in a dictionary that is itself
an entry "TEST" in the database settings.
Refs #21775
Thanks Josh Smeaton for review.
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.
Replaced them with per-database options, for proper multi-db support.
Also toned down the recommendation to tie transactions to HTTP requests.
Thanks Jeremy for sharing his experience.
Raphaël Hertzog
Tim Graham
Caio Ariede
Aymeric Augustin
Andrei Kulakov
Loic Bistuer
Claude Paroz
Shai Berger
Anubhav Joshi
Marc Tamlyn
Berker Peksag
Alasdair Nicol
Anssi Kääriäinen
Andrew Godwin
James Aylett