#27564: `refresh_from_db()` should return the model instance instead of None
-------------------------------------+-------------------------------------
Reporter: Tom | Owner: nobody
Type: | Status: closed
Cleanup/optimization |
Component: Database layer | Version: 1.10
(models, ORM) |
Severity: Normal | Resolution: wontfix
Keywords: | Triage Stage:
| Unreviewed
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 Aymeric Augustin):
In fact the reason why `refresh_from_db` exists is **not** to return an
updated object, but instead to refresh it in place so that other pieces of
code that have kept a reference to this instance see the updated data.
To return a copy, `Thing.objects.get(pk=thing.pk)` is hardly longer than
`thing.refresh_from_db()` and (in my opinion) should be preferred because
it's explicit.
A shorter and more idiomatic way to write:
{{{
assert all(model.refresh_from_db().status == Something for model in
queryset)
}}}
is
{{{
assert all(model.status == Something for model in queryset.all())
}}}
(The `.all()` creates a new queryset that forces a new database query.)
If `refresh_from_db()` returns the updated instance, it will be used in
situations when it isn't necessary and where the regular, safer APIs that
don't involve in place mutations are a better choice.
--
Ticket URL: <https://code.djangoproject.com/ticket/27564#comment:4>
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