Type hint for `Request.query_params` does not match documentation

[jmullercuber]

The API documentation for the Request class indicates the query_params may be MultiDict or None: https://aws.github.io/chalice/api.html#Request.query_params

However, the type hint associated with the class definition does not match the above:

chalice/chalice/app.pyi

Lines 77 to 78 in 8df8b59

	class Request:
	query_params = ... # type: Dict[str, str]

The impact of this issue is that the mismatch makes it more difficult for developers to use the API as their IDE will suggest one thing about query_params (they don't need to check for None values) while in reality they do.

A minimal example of such is below, with comments.

from chalice import Chalice, Response

DEFAULT_NAME = "world"

app = Chalice(app_name="hello-world")


@app.route("/", methods=["GET"])
def hello_world():
    # This part is not obvious given chalice's current type hints
    # `or {}` is a work-around to ensure params is Dict type if chalice sets it as None
    params = app.current_request.query_params or {}

    # works for Dict/MultiDict, but not NoneType
    name = params.get("name", DEFAULT_NAME)
    
    return {"message": f"hello {name}"}

This is an issue on the latest release 1.22.3

[jmullercuber]

Related PRs/issues: #1132 , #1055

[jamesls]

We should update the type hint associated with the class definition. I would like to change the value to always be a dict type, but we'd have to wait for a major version bump to make that change.

[jmullercuber]

thanks for addressing this! Looking forward to the next release.