#22268: values_list() on a ManyToManyField returns extra None's when iterated
over.
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Reporter: k_sze | Owner:
Type: Bug | anubhav9042
Component: Database layer | Status: assigned
(models, ORM) | Version: master
Severity: Normal | Resolution:
Keywords: orm, values_list, | Triage Stage: Accepted
ManyToManyField | Needs documentation: 0
Has patch: 0 | Patch needs improvement: 0
Needs tests: 0 | UI/UX: 0
Easy pickings: 0 |
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Comment (by k_sze):
On the one hand, I do understand that a change in behaviour would break
backward compatibility. On the other hand, I tend to agree with
[comment:10 comment:10] here, in that the behaviour should be modified in
the future. To me, the correct behaviour would be to not include the
''extra'' `None`s. In my example, the ones from the null `year_of_birth`
are fine and should be included. Another point of consideration that I
would raise is whether there is any reason to believe that people are
''relying'' on the current behaviour (I think it would be quite strange
for people to be ''relying on ambiguity'').
Would it be OK to document it as a ''quirk'' that is subject to change in
the future, and not as the ''correct bahaviour''?
Regarding [comment:11 comment:11], I think there are possible legitimate
uses for this kind of query. For instance, if you want a Cartesian product
count of some M2M relation, and then run it through the Python
collections.Counter or something.
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Ticket URL: <https://code.djangoproject.com/ticket/22268#comment:13>
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