Set in params treated differently as List

[finswimmer]

Hey,

if one of my params contains a list, httpx happily repeat the parameter in the URL for each value.

httpx.Request('GET', 'http://example.com', params={"a": [1, 2 ,3]}).url
# URL('http://example.com?a=1&a=2&a=3')

I would expect this behavior as well, if the parameter contains a set. But instead the set is turned into a string.

httpx.Request('GET', 'http://example.com', params={"a": {1, 2 ,3}}).url
# URL('http://example.com?a=%7B1%2C%202%2C%203%7D')

Is this a feature or a bug? 😃

I'm using httpx version 0.25.0.

fin swimmer

[lovelydinosaur]

Is this a feature or a bug?

Neither, it's Python.

[finswimmer]

Neither, it's Python.

Hm, can you please add some more information to this?

[karpetrosyan]

You've used an unsupported type, and you're getting unexpected results. If you use an IDE tool or mypy for Python typing, it should probably warn you that the type you are using is incorrect.

type you have used for params is: typing.Dict[str, set[int]]

Supported types:

QueryParamTypes = Union[
    "QueryParams",
    Mapping[str, Union[PrimitiveData, Sequence[PrimitiveData]]],
    List[Tuple[str, PrimitiveData]],
    Tuple[Tuple[str, PrimitiveData], ...],
    str,
    bytes,
] 

Valid examples:

[("test", "test"), ] #  valid for List[Tuple[str, PrimitiveData]]
{"test": "test} # valid for Mapping[str, Union[PrimitiveData, Sequence[PrimitiveData]]]

[lovelydinosaur]

I'm just being whimsical.
I mean it's not a strongly typed language, and behaviours for unexpected types are often a bit under-defined.

Would {i, you, one} expect a set here to?...

• be coerced into a str, as the default behaviour for any unexpected types.
• be coerced into a list, as the default behaviour for any iterables.
• raise a type error, because we're being strict about the allowed types here.

[karpetrosyan]

It's more natural to let Python work as it should. It will be very complex for us to track these kinds of cases.

[finswimmer]

Thanks for clarification 👍 Makes sense.

be coerced into a list, as the default behavior for any iterables.

This was my expectation. I stumbled about this issue, while migrating my code from requests to httpx and it used to work before. So you can take this as a feature request 😃