#23405: Blank-able CharFields require default=''
----------------------------+------------------------------------
Reporter: yuvadm | Owner: coldmind
Type: Bug | Status: assigned
Component: Migrations | Version: 1.7
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
----------------------------+------------------------------------
Comment (by coldmind):
Replying to [comment:15 andrewgodwin]:
> Just to put some input in on this - the weird quirk of defaulting to
empty string is a feature of the text fields themselves, and it's not just
text fields (for example, one should argue that IntegerFields with
`blank=True, null=False` should have a default value of 0 rather than
prompting).
>
> Thus, I think it needs to be addressed on the fields themselves. I doubt
we can change what `has_default()` returns, but there could be an argument
made for adding a new `needs_default()` method, which returns if the field
can happily live without a default (so, for example, a `CharField` would
return `False`, and the new `BooleanField` would return `True` as it needs
an explicit default, though that would get caught in validation).
>
> Then, autodetector can be modified to also check for `needs_default() =
True`. We should also probably upgrade it and warn if it has `unique` set
on it, as doing this when you're adding a `NOT NULL` column is usually a
bad idea if tsuch checkshere's data in the table.
Thanks, this is a good idea.
Few questions about it.
1. `needs_default()` should return value according to field attributes?
For example, for `TextField`, it be like
{{{
def needs_default(self):
if self.blank and not self.null and self.default is NOT_PROVIDED:
return False
return True
}}}
, right?
2. If 1 question is right, the default value for `needs_default` should be
`True`?
3. Do we need override `needs_default` for all fields, or only for
"special" ?
--
Ticket URL: <https://code.djangoproject.com/ticket/23405#comment:16>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/064.8afd2b2dc9991749db10adf3162f87ee%40djangoproject.com.
For more options, visit https://groups.google.com/d/optout.
