URI parameters appear to be duplicated on retry

[joeapearson]

Given this script:

Mix.install([
  {:req, "0.3.1"}
])

require Logger

Req.new(url: "https://httpbin.org/status/408", params: [test: "a"])
|> Req.Request.append_request_steps(
  log_request: fn request ->
    Logger.debug("#{request.method} #{URI.to_string(request.url)}")

    request
  end
)
|> Req.get!()

… I get this output:

11:09:15.145 [debug] get https://httpbin.org/status/408?test=a

11:09:15.692 [error] retry: got response with status 408, will retry in 1000ms, 3 attempts left

11:09:16.694 [debug] get https://httpbin.org/status/408?test=a&test=a

11:09:16.778 [error] retry: got response with status 408, will retry in 2000ms, 2 attempts left

11:09:18.780 [debug] get https://httpbin.org/status/408?test=a&test=a&test=a

11:09:18.868 [error] retry: got response with status 408, will retry in 4000ms, 1 attempt left

11:09:22.871 [debug] get https://httpbin.org/status/408?test=a&test=a&test=a&test=a

Notice how on the first request, I have a single test=a URI parameter, but on each subsequent attempt the URI parameters are duplicated.

Please let me know if I've done something wrongly here!

[wojtekmach]

This is definitely a bug, thank you for reporting it. I think what is happening is the put_params/1 step merges the params into the URI but keeps the :params option around. And when we hit the error, the retry/1 step will take the request and run it again but now it has the url (with params applied) and the :params option, so it will append the params again. Don't know off the top of my head what's the best way to handle it, we need to either change put_params or retry or both.