test(http): cover pooled redirect with hackney

Reproduces the Hackney 1.25 pooled redirect cleanup issue which can surface as :req_not_found when the adapter returns a Ref and the body is later fetched.

test/pleroma/http/hackney_redirect_regression_test.exs

@@ -0,0 +1,151 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.HTTP.HackneyRedirectRegressionTest do
+  use ExUnit.Case, async: false
+
+  alias Pleroma.HTTP.AdapterHelper.Hackney, as: HackneyAdapterHelper
+
+  setup do
+    {:ok, _} = Application.ensure_all_started(:hackney)
+
+    {:ok, server} = start_server()
+    on_exit(fn -> stop_server(server) end)
+
+    {:ok, server: server}
+  end
+
+  test "pooled redirects work with follow_redirect disabled", %{server: server} do
+    url = "#{server.base_url}/redirect"
+    uri = URI.parse(url)
+
+    adapter_opts =
+      HackneyAdapterHelper.options(
+        [pool: :media, follow_redirect: false, no_proxy_env: true],
+        uri
+      )
+
+    client = Tesla.client([Tesla.Middleware.FollowRedirects], Tesla.Adapter.Hackney)
+
+    assert {:ok, %Tesla.Env{status: 200, body: "ok"}} =
+             Tesla.request(client, method: :get, url: url, opts: [adapter: adapter_opts])
+  end
+
+  defp start_server do
+    {:ok, listener} =
+      :gen_tcp.listen(0, [
+        :binary,
+        active: false,
+        packet: :raw,
+        reuseaddr: true,
+        ip: {127, 0, 0, 1}
+      ])
+
+    {:ok, {{127, 0, 0, 1}, port}} = :inet.sockname(listener)
+
+    {:ok, acceptor} =
+      Task.start_link(fn ->
+        accept_loop(listener)
+      end)
+
+    {:ok, %{listener: listener, acceptor: acceptor, base_url: "http://127.0.0.1:#{port}"}}
+  end
+
+  defp stop_server(%{listener: listener, acceptor: acceptor}) do
+    :ok = :gen_tcp.close(listener)
+
+    if Process.alive?(acceptor) do
+      Process.exit(acceptor, :normal)
+    end
+  end
+
+  defp accept_loop(listener) do
+    case :gen_tcp.accept(listener) do
+      {:ok, socket} ->
+        serve(socket)
+        accept_loop(listener)
+
+      {:error, :closed} ->
+        :ok
+
+      {:error, _reason} ->
+        :ok
+    end
+  end
+
+  defp serve(socket) do
+    with {:ok, data} <- recv_headers(socket),
+         {:ok, path} <- parse_path(data) do
+      case path do
+        "/redirect" ->
+          send_response(socket, 302, "Found", [{"Location", "/final"}], "")
+
+        "/final" ->
+          send_response(socket, 200, "OK", [], "ok")
+
+        _ ->
+          send_response(socket, 404, "Not Found", [], "not found")
+      end
+    else
+      _ -> :ok
+    end
+
+    :gen_tcp.close(socket)
+  end
+
+  defp recv_headers(socket, acc \\ <<>>) do
+    case :gen_tcp.recv(socket, 0, 1_000) do
+      {:ok, data} ->
+        acc = acc <> data
+
+        if :binary.match(acc, "\r\n\r\n") != :nomatch do
+          {:ok, acc}
+        else
+          if byte_size(acc) > 8_192 do
+            {:error, :too_large}
+          else
+            recv_headers(socket, acc)
+          end
+        end
+
+      {:error, _} = error ->
+        error
+    end
+  end
+
+  defp parse_path(data) do
+    case String.split(data, "\r\n", parts: 2) do
+      [request_line | _] ->
+        case String.split(request_line, " ") do
+          [_method, path, _protocol] -> {:ok, path}
+          _ -> {:error, :invalid_request}
+        end
+
+      _ ->
+        {:error, :invalid_request}
+    end
+  end
+
+  defp send_response(socket, status, reason, headers, body) do
+    base_headers =
+      [
+        {"Content-Length", Integer.to_string(byte_size(body))},
+        {"Connection", "close"}
+      ] ++ headers
+
+    iodata =
+      [
+        "HTTP/1.1 ",
+        Integer.to_string(status),
+        " ",
+        reason,
+        "\r\n",
+        Enum.map(base_headers, fn {k, v} -> [k, ": ", v, "\r\n"] end),
+        "\r\n",
+        body
+      ]
+
+    :gen_tcp.send(socket, iodata)
+  end
+end