#31261: Add support for defining models.Choices fields with dict, tuple, set and
list values.
-------------------------------------+-------------------------------------
Reporter: Tom Forbes | Owner: nobody
Type: New feature | Status: closed
Component: Database layer | Version: master
(models, ORM) |
Severity: Normal | Resolution: needsinfo
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by Tom Forbes):
I can construct a `Choices` object with mutable values, it fails if
`.choices` is called on the object but otherwise it works fine.
I've found that the current code checks if the value is a list or a tuple,
so something like this is currently supported:
{{{
SOME_KEY = [1, "display value]
}}}
I can't find tests for this and didn't know this was possible, but this
does make it quite hard to make work as described in the ticket
description without a lot of magic.
However what what about abandoning the idea of defining things using
literals and use a special class:
{{{
class MoonMissions(models.IntegerChoices):
...
SUCCESSFUL_MISSIONS = ChoiceSet(APOLLO_10, APOLLO_11)
SUCCESS_GROUPING = DisplayGroup({
"Failed": FAILED_MISSIONS,
"Successful": SUCCESSFUL_MISSIONS
})
}}}
From the point of view of the metaclass this makes things a _lot_ simpler,
as you don't need to try and work out if the given value is an enum value,
a value with a display.
It's not as nice as using a literal but it does sidestep a lot of issues.
Another thing that might be simpler to do with a class is "stitching up"
the choice/group values. Ideally we'd want the values of
`SUCCESSFUL_MISSIONS` to be an Enum object, not the primitive type (or the
tuple type if it has a display value), so the code would have to update
these classes after the enum is initialized and all enum members created,
replacing the raw references with their corresponding Enum objects.
--
Ticket URL: <https://code.djangoproject.com/ticket/31261#comment:9>
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