Re: [Django] #11541: F() expressions don't allow assignment of Foreign Key values on instances
Django
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Reporter: Russell Keith-Magee | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 1.1-beta
(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 Abhijeet Viswa):
I gave a shot at fixing this ticket. However, I got stuck real fast. F
expressions aren't resolved until the queryset is evaluated. However, the
test to check if the right-value is an instance of the forward relation's
class is performed during assignment. The only solution I could think of
is to defer the test for F expressions until queryset evaluation.
Maintainers, would this be the best approach?
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Ticket URL: <https://code.djangoproject.com/ticket/11541#comment:6>
Django <https://code.djangoproject.com/>
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Django
-------------------------------------+-------------------------------------
Reporter: Russell Keith-Magee | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 1.1-beta
(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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* cc: Abhijeet Viswa (added)
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Ticket URL: <https://code.djangoproject.com/ticket/11541#comment:7>
Django
-------------------------------------+-------------------------------------
Reporter: Russell Keith-Magee | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 1.1-beta
(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 Simon Charette):
> The only solution I could think of is to defer the test for F
expressions until queryset evaluation.
Abhijeet, the check can likely be deferred `if hasattr(value,
resolve_expression)`.
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Ticket URL: <https://code.djangoproject.com/ticket/11541#comment:8>
Django
-------------------------------------+-------------------------------------
Reporter: Russell Keith-Magee | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 1.1-beta
(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 Abhijeet Viswa):
Marten Kenbeek pointed out to me that `F`expression can be assigned to the
`attname` attribute of the Model instance. So,
`test_gmbh.point_of_contact_id` can be assigned `F('ceo')` to have the
intended effect. However, I don't think this is documented. Would
documenting this be enough to close this ticket? Or should F expressions
be assignable to the relation descriptors?
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Ticket URL: <https://code.djangoproject.com/ticket/11541#comment:9>
Django
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| Pandey
Type: Bug | Status: assigned
Component: Database layer | Version: 1.1-beta
(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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* owner: nobody => Aman Pandey
* status: new => assigned
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Ticket URL: <https://code.djangoproject.com/ticket/11541#comment:10>