#28731: Passing an empty Q() to a When inside a Case causes an OperationError
-------------------------------------+-------------------------------------
Reporter: Tom van Bussel | Owner: Tim
| Martin
Type: Bug | Status: assigned
Component: Database layer | Version: 1.11
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
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 Tim Martin):
After a bit of digging, I found the rationale for this behaviour in
#28211. The argument seems to be that it's common to do something like:
{{{
filters = Q()
if condition:
filters |= Q(x=1)
if other_condition:
filters |= Q(y=2)
}}}
I'm not sure I agree that this is the right design but there is at least a
rationale here, and it's been like this for many years now so I don't
think changing it is viable. This rationale supports the idea that empty
Q() objects are legitimate steps in building up a query, but shouldn't be
used directly. I'll make this report an explicit error rather than invalid
SQL.
--
Ticket URL: <https://code.djangoproject.com/ticket/28731#comment:13>
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