#33647: bulk_update silently truncating values for size limited fields
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Reporter: jerch | Owner: nobody
Type: | Status: new
Uncategorized |
Component: Database | Version: 4.0
layer (models, ORM) |
Severity: Normal | Keywords:
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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On postgres backend, `bulk_update` passes overlong values for size limited
fields along without any notification/exception, instead truncating the
value.
Repro:
{{{
#!div style="font-size: 80%"
Code highlighting:
{{{#!python
# some model to repro
class TestModel(models.Model):
name = models.CharField(max_length=32)
# in the shell
>>> from bulk_test.models import TestModel
>>> tm=TestModel(name='hello')
>>> tm.save()
>>> tm.name
'hello'
>>> tm.name='m'*100
>>> tm.save() # good, raises:
...
django.db.utils.DataError: value too long for type character varying(32)
>>> TestModel.objects.all().values('name')
<QuerySet [{'name': 'hello'}]>
>>> TestModel.objects.all().update(name='z'*100) # good, raises as
well:
...
django.db.utils.DataError: value too long for type character varying(32)
>>> TestModel.objects.all().values('name')
<QuerySet [{'name': 'hello'}]>
>>> TestModel.objects.bulk_update([tm], ['name']) # not raising,
instead truncating:
1
>>> TestModel.objects.all().values('name')
<QuerySet [{'name': 'mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm'}]>
}}}
}}}
Not sure, if this is intended/expected behavior, well it is inconsistent
to `.save` or `.update`, which both raise here. I only tested postgres
backend for this, it may apply to other size limiting databases as well
(sqlite itself is not affected, as it does not limit values).
If this is intended, it may be a good idea to at least document the
slightly different behavior, so users are aware of it, and can prepare
their code to avoid silent truncation with follow-up errors. A better way
prolly would fix `bulk_update` to spot value overflows and raise, but I am
not sure, if thats feasible.
--
Ticket URL: <https://code.djangoproject.com/ticket/33647>
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