Improve JSON typing in requests.requests.models

[AdemOdza]

Added a dict[str, Any] type to the Response json() method and Request.

The Request class expects a serializable object (https://github.com/psf/requests/blob/main/src/requests/models.py#L510)

The Response.json() method returns a deserialized JSON string (https://github.com/psf/requests/blob/main/src/requests/models.py#L958)

This was causing issues with my type checker (MyPy) so I thought I would add it in.

def test(response: Response) -> dict[str, Any]:
  res = response.json()
  return res
  # MyPy complains because this function returns an Any object rather than a python 
  # JSON object

[Akuli]

The .json() method doesn't necessarily return a dict:

>>> import requests
>>> requests.get('https://httpbin.org/base64/WzEsMiwzXQ==').json()
[1, 2, 3]

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

openlibrary (https://github.com/internetarchive/openlibrary)
+ openlibrary/core/admin.py: note: In function "_get_loan_counts_from_graphite":
+ openlibrary/core/admin.py:81: error: Invalid index type "int" for "dict[str, Any]"; expected type "str"  [index]
+ openlibrary/core/admin.py: note: In function "_get_visitor_counts_from_graphite":
+ openlibrary/core/admin.py:126: error: Invalid index type "int" for "dict[str, Any]"; expected type "str"  [index]

cwltool (https://github.com/common-workflow-language/cwltool)
+ cwltool/resolver.py: note: In function "resolve_ga4gh_tool":
+ cwltool/resolver.py:82:20: error: "str" has no attribute "get"  [attr-defined]
+ cwltool/resolver.py:83:36: error: "str" has no attribute "get"  [attr-defined]

[AdemOdza]

The .json() method doesn't necessarily return a dict:

>>> import requests
>>> requests.get('https://httpbin.org/base64/WzEsMiwzXQ==').json()
[1, 2, 3]

Oh right, of course. Would there be a better way to type this other than Any?

[Akuli]

Unfortunately, Any is the best we can do now. If we return dict[str, Any] | something, mypy will still complain when you try to use the return value as a list, because it thinks the return value could be a dict[str, Any] and you're not handling that. Ideally we would have something like AnyOf to work around this.

For your use case, you can return cast(dict[str, Any], response.json()).

[Akuli]

Maybe adding assert isinstance(res, dict) is better than a cast:

from requests import Response
from typing import Any

def test(response: Response) -> dict[str, Any]:
    res = response.json()
    assert isinstance(res, dict)
    return res

[AdemOdza]

Thanks for the suggestions! I'll go ahead and close this PR since I was wrong