[Django] #34354: Behaviour by design? models. Manager annotate() queryset conflict with models.Model

[Django]

#34354: Behaviour by design? models. Manager annotate() queryset conflict with
models.Model
-----------------------------------------+--------------------------
Reporter: David Pratten | Owner: nobody
Type: Bug | Status: new
Component: contrib.admin | Version: 4.1
Severity: Normal | Keywords: Possible
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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With

{{{
class MyPapersManager(models.Manager):
def get_queryset(self):
return
super().get_queryset().annotate(count_of_keywords=Coalesce(Count('keywordspapers'),0))
# .filter(in_scope=True) works fine here
}}}

{{{
class MyPapers(models.Model):
objects = MyPapersManager()
count_of_keywords = models.IntegerField() # generated by manager
above!
keywordspapers = models.ManyToManyField(to='Keywords', blank=True)
}}}

and
{{{
class MyPapersAdmin(admin.ModelAdmin):
list_display = ("count_of_keywords",)
}}}

Results in runtime error {{{The annotation 'count_of_keywords' conflicts
with a field on the model.}}}

However, f I remove the {{{count_of_keywords}}} field from the
models.Model I get a start up error: {{{<class
'literature.admin.MyPapersAdmin'>: (admin.E108) The value of
'list_display[3]' refers to 'count_of_keywords', which is not a callable,
an attribute of 'MyPapersAdmin', or an attribute or method on
'literature.MyPapers'.}}}

What is the correct way to add a computed field to a model in Admin land?

Thanks

David

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Ticket URL: <https://code.djangoproject.com/ticket/34354>
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