[Django] #23657: Migrations framework doesn't properly handle factory-generated base classes.
Django
classes.
----------------------------+--------------------
Reporter: jfialkoff | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
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It is sometimes useful to construct models using factories. The code below
shows one example of this. Other useful factories may or may not have
fields (e.g., I have a base class factory that I use to add properties to
an object with the urls for the object listing, edit page, create page and
delete page).
{{{
def address_mixin_factory(address_required=True, city_required=True,
state_required=True):
# build base abstract model with the fields address, city and state
and assign blank=True/False depending on the arguments.
return AddressMixin
class FullAddress(address_mixin_factory(), models.Model):
pass
class PartialAddress(address_mixin_factory(address_required=False),
models.Model):
pass
}}}
When you use Django migrations to migrate a model like this, the resulting
migration file will have something like `bases=(AddressMixin,
models.Model)` in the call to `CreateModel` where, instead, we would want
`bases=(address_mixin_factory(), models.Model)`. Also, while I have not
tested this, I'm assuming the fields specified in the call to
`CreateModel` will also be lacking the fields contributed by the factory-
created base class.
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Ticket URL: <https://code.djangoproject.com/ticket/23657>
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Django
classes.
Reporter: jfialkoff | Owner: nobody
Type: Bug | Status: new
Component: Migrations | Version: 1.7
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by carljm):
* needs_better_patch: => 0
* needs_tests: => 0
* needs_docs: => 0
Comment:
This strikes me as an atypical edge-case where the only feasible answer is
"modify the generated migration." Migration files are editable Python code
for a reason; autodetection will never handle everything someone might do.
In this case, I don't think it is possible for the autodetector to handle
this the way you want - it can't know via runtime introspection that your
base class was created via factory. (Well, with `__qualname__` in Python 3
it might be possible, but we have to maintain Python 2 compatibility for
quite some time still).
Closing wontfix; if any other core dev with more hands-on migration
experience disagrees, feel free to reopen.
--
Ticket URL: <https://code.djangoproject.com/ticket/23657#comment:1>
Django
classes.
Reporter: jfialkoff | Owner: nobody
Type: Bug | Status: closed
Component: Migrations | Version: 1.7
Severity: Normal | Resolution: wontfix
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Needs documentation: 0
Easy pickings: 0 | UI/UX: 0
Changes (by carljm):
* status: new => closed
* resolution: => wontfix
--
Ticket URL: <https://code.djangoproject.com/ticket/23657#comment:2>