OpenAPI parameters with style: form & explode: true

[shivjm]

I have this in my OpenAPI spec:

  /store/foos/page:
    get:
      tags:
        - foo-controller
      operationId: getFoos
      parameters:
        - name: params
          in: query
          required: true
          schema:
            type: object
            additionalProperties:
              type: string
          explode: true
          style: form

@rtk-query/openapi-codegen generates what looks like the correct code:

    getFoos: build.query<GetFoosApiResponse, GetFoosApiArg>({
      query: (queryArg) => ({
        url: `/store/foos/page`,
        params: { params: queryArg.params },
      }),
    }),

/* … */

export type GetFoosApiResponse = /** status 200 OK */ FoosPage;
export type GetFoosApiArg = {
  params: {
    [key: string]: string;
  };
};

And I call it like this (with React hooks):

const { data } = useGetFoosQuery({ params: { foo: "bar", baz: "quux" } });

I’d expect this to make a request with a query string like this:

?foo=bar&baz=quux

Instead, the query string looks like this, because it uses URLSearchParams for serialization and the outer object is not flattened:

?params=%5Bobject+Object%5D

What’s the right way to handle this? I know I can pass a custom paramsSerializer, but that function is only passed the parameters, so it can’t reference the explode or style values and produce the correct output. (I also see that those values are the defaults, which makes me wonder whether this is actually a bug.)