Impossible to adhere to AIP suggestions for AIP-136 when using google.api.HttpBody and have values in request path

[achew22]

In AIP-136, and in the associated linter entry it is suggested that the following would not be allowed:

// Incorrect.
rpc CheckoutBook(CheckoutBookRequest) returns (CheckoutBookResponse) {
  option (google.api.http) = {
    post: "/v1/{name=publishers/*/books}:checkout"
    // `body: "*"` should be included.
  };
}

I believe the implied form of CheckoutBookRequest would be something like:

message CheckoutBookRequest {
  string name = 1;
  string some_other_field = 2;
  // even more fields
}

This seems reasonable in the general case. There is, however, an edge case in the somewhat bizarre event where you're using google.api.HttpBody to provide a webhook endpoint where you can't control the caller to send you structured data. Unfortunately I can't even force JSON, I'm going to be getting application/x-www-form-urlencoded encoded data posted as the whole body. I could put it into a body: "string_field" directly, but then I would be asking the parser to infer the encoding, which feels unnecessary since there is a nice way to get the content_type. I believe this functionally is akin to HTTPOverRPC from days of old (sorry for bringing that up if you remember it). This may be considered a thing that is beyond the scope for AIP, but I believe the only correct form for using this would be:

// Possibly incorrect?
rpc HandleWebhook(HandleWebhookRequest) returns (google.api.HttpBody) {
  option (google.api.http) = {
    post: "/v1/{name=webhooks/*}:handle"
    body: "request"
  };
}

message HandleWebhookRequest {
  string name = 1;
  google.api.HttpBody request = 2;
}

Unfortunately this causes a lint error. I could then add a lint exception for api-linter: core::0136::http-body=disabled to the HandleWebhook RPC, but I want to make sure that I'm not missing something obvious.

Is this what you would expect?