#27846 closed Bug (fixed)
refresh_from_db() doesn't clear reverse OneToOneFields
Reported by: | Keith Hostetler | Owned by: | Paulo |
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Component: | Database layer (models, ORM) | Version: | 1.10 |
Severity: | Normal | Keywords: | refresh_from_db OneToOneField |
Cc: | Andrey Fedoseev, Berker Peksag | Triage Stage: | Accepted |
Has patch: | yes | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description (last modified by )
Sorry for the poor summary, it is difficult to explain in words. I have a project to demo this bug attached to this ticket, but I will try to explain the bug anyway in steps and the setup.
Setup:
- 2 models (A and B)
- B has a OneToOne to A
- Both A and B have a field (ie TextField)
- Setup either a signal or override save() for A to update B's TextField to equal that of A's on save() or post_save for signals
Steps:
- Create instance of A
- Get another copy of the instance of A via A.objects.get()
- Create instance of B using the copy of the instance of A
- Do refresh_from_db() on original instance of A
- Try to access B from A
The project I have provided is a slim version of this problem that demonstrates it with signals, overriden save(), and basic set and save inside the test. The basic set and save works, but the other two fail when using the above steps. Run the test suite to see.
Attachments (1)
Change History (11)
by , 8 years ago
Attachment: | django_1_10_refresh_from_db_bug.rar added |
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comment:1 by , 8 years ago
Type: | Uncategorized → Bug |
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comment:2 by , 8 years ago
Description: | modified (diff) |
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comment:3 by , 8 years ago
Summary: | refresh_from_db() does not create "soft links" on model_instances that are pointed to by another model's OneToOneField → refresh_from_db() doesn't clear reverse OneToOneFields |
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Triage Stage: | Unreviewed → Accepted |
comment:4 by , 7 years ago
Owner: | changed from | to
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Status: | new → assigned |
comment:5 by , 7 years ago
Cc: | added |
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comment:6 by , 7 years ago
Hello,
What do you all think about clearing the fields cache entirely on refresh_from_db()?
This would cover similar bugs where a many to one or many to many relationship is cached.
The only case we can't cover is fields prefetched to custom attributes.
comment:7 by , 7 years ago
Cc: | added |
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I think this is fixable but I'm not sure without trying to write a patch. This case may be discussed in ticket:901#comment:36 It looks like the issue is that
refresh_from_db()
clears concrete fields but doesn't clear reverse relations.