Make MultiValueDict more consistent

[Yaroslav Pankovych]

I was working with query parameters and found that .pop() and .get() both have different logic.

I assume that .pop() should be the same as .get(), but the key should get deleted afterward.

Here's an example:

In [1]: from django.utils.datastructures import MultiValueDict

In [2]: data = MultiValueDict({"name": ["Yaroslav", "Clara"], "age": [22, 32]})

In [3]: data.get("name")
Out[3]: 'Clara'

In [4]: data.pop("name")
Out[4]: ['Yaroslav', 'Clara']

As you can see, we've got a single item for .get(), and a list for .pop(), which is confusing.

We should have all of that synced. .get() with .getlist(), and .pop() with .poplist().

Here's how it looks like after I've done some changes:

In [4]: data.pop("name")
Out[4]: 'Clara'

In [5]: data.poplist("name")
Out[5]: ['Yaroslav', 'Clara']

This is breaking change probably.

[Yaroslav Pankovych]

​https://github.com/django/django/pull/14945

[Mariusz Felisiak]

Thanks for the suggestion, however I don't think it's worth breaking backwards compatibility. We need to reach a strong consensus on the DevelopersMailingList before moving it forward. Please ​follow the triaging guidelines with regards to wontfix tickets and take this to DevelopersMailingList.