#12708: Django raises DoesNotExist when consulting an empty ForeignKey field
-------------------------------------+-------------------------------------
Reporter: lsaffre | Owner: nobody
Type: Uncategorized | Status: closed
Component: Database layer | Version: master
(models, ORM) | Resolution: invalid
Severity: Normal | Triage Stage:
Keywords: ForeignKey | Unreviewed
DoesNotExist | Needs documentation: 0
Has patch: 0 | Patch needs improvement: 0
Needs tests: 0 | UI/UX: 0
Easy pickings: 0 |
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Changes (by Luis):
* ui_ux: => 0
* type: => Uncategorized
* severity: => Normal
* easy: => 0
Comment:
It shouldn't be considered invalid, even worse to be considered as a
"consistent behavior". Reason: this only happens with related fields, and
not with normal fields.
If I have:
class B(Model):
name = CharField(max_length=30) #example
class A(Model):
#neither of these fields allow null
count = PositiveSmallIntegerField()
ref_a = ForeignKey(B)
And issue:
a = A()
...
a.count #will return
a.ref_a #will raise exception
That does not let me traverse model properties without asking for
forgiveness everytime. Why throwing DoesNotExist error and not throwing a
ValueError or AttributeError for count property? Either trigger an error
(ValueError, AttributeError, whatever) in non-related properties OR (xor)
stop throwing errors when a FK has a null value (and does not accept it).
--
Ticket URL: <https://code.djangoproject.com/ticket/12708#comment:2>
Django <https://code.djangoproject.com/>
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