In some cases, this could lead to migrations written with Python 2
being incompatible with Python 3.
Thanks Tim Graham for the report and Loïc Bistuer for the advices.
Avoided introducing a new regex-based SQL splitter in the migrations
framework, before we're bound by backwards compatibility.
Adapted this change to the legacy "initial SQL data" feature, even
though it's already deprecated, in order to facilitate the transition
to migrations.
sqlparse becomes mandatory for RunSQL on some databases (all but
PostgreSQL). There's no API to provide a single statement and tell
Django not to attempt splitting. Since we have a more robust splitting
implementation, that seems like a good tradeoff. It's easier to add a
new keyword argument later if necessary than to remove one.
Many people contributed to both tickets, thank you all, and especially
Claude for the review.
Refs #22401.
Changed the migration autodetector to remove models last so that FK
and M2M fields will not be left as dangling references. Added a check
in the migration state renderer to error out in the presence of
dangling references instead of leaving them as strings. Fixed a bug
in the sqlite backend to handle the deletion of M2M fields with
"through" models properly (i.e., do nothing successfully).
Thanks to melinath for report, loic for tests and andrewgodwin and
charettes for assistance with architecture.
Changed the migration autodetector to remove models last so that FK
and M2M fields will not be left as dangling references. Added a check
in the migration state renderer to error out in the presence of
dangling references instead of leaving them as strings. Fixed a bug
in the sqlite backend to handle the deletion of M2M fields with
"through" models properly (i.e., do nothing successfully).
Thanks to melinath for report, loic for tests and andrewgodwin and
charettes for assistance with architecture.
This commit reverts 69d4b1c and tackle the issue from a different angle.
Models remain present in the project state, but are now ignored by the
autodetector.
Added reversible property to RunPython so that migrations will not
refuse to reverse migrations including RunPython operations, so long as
reverse_code is set in the RunPython constructor. Included tests to
check the reversible property on RunPython and the similar RunSQL.
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.
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.
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.
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.
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.
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.
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.