Messages not recognized when using proxy

[ppatrzyk]

Function is_connection_message/2 seems to fail when proxy is being used. Minimal example:

require Mint.HTTP
require Logger

opts = [proxy: {:http, "localhost", 8118, []}]
{:ok, conn} = Mint.HTTP.connect(:http, "httpbin.org", 80, opts)
{:ok, conn, request_ref} = Mint.HTTP.request(conn, "GET", "/json", [], "")

receive do
  msg ->
    is_ok = Mint.HTTP.is_connection_message(conn, msg)
    is_ok |> inspect() |> Logger.warn()
    msg |> inspect() |> Logger.warn()
end

I see output that message is not related to the connection - this is incorrect. Changing opts to empty list (i.e., connection without proxy) fixes the issue.

Details:

• Mint 1.4.2
• Elixir 1.13.0
• Erlang/OTP 24
• for proxy I used Privoxy