Re: [Django] #35915: QueryDict __getitem__ returns an empty list when the value is an empty list (was: QueryDict __getitem__ returns list which is surpising)

[Django]

#35915: QueryDict __getitem__ returns an empty list when the value is an empty list
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Reporter: Nguyễn Hồng Quân | Owner: (none)
Type: Cleanup/optimization | Status: new
Component: HTTP handling | Version: 5.1
Severity: Normal | Resolution:
Keywords: querydict | 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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Changes (by Sarah Boyce):

* stage: Unreviewed => Accepted
* summary: QueryDict __getitem__ returns list which is surpising =>
QueryDict __getitem__ returns an empty list when the value is an empty
list

Comment:

> Could we change this behavior? I know that we don't have a perfect
solution, but returning None in this case is less bad than empty list [],
because it is easier to annotate type.

It's been this way a very long time, I'm not sure what the implications of
changing it would be (in terms of compatibility). I also think changing it
for easier type annotations is not a strong argument here. You could raise
this topic on the [https://forum.djangoproject.com/ Django forum] and get
others opinions if you wish to change it.

That being said, I think a docs adjustment is required (note that the
docstring states `Return the last data value for this key, or [] if it's
an empty list; raise KeyError if not found.`).
Accepting on that basis.
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Ticket URL: <https://code.djangoproject.com/ticket/35915#comment:1>
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