fix(http): treat an empty proxy_url as no proxy

changelog.d/empty-proxy-url.fix

@@ -0,0 +1 @@
+HTTP: treat an empty proxy_url as no proxy; with Hackney 4 it made every outgoing request fail

lib/pleroma/http/adapter_helper.ex

@@ -20,8 +20,9 @@ defmodule Pleroma.HTTP.AdapterHelper do
 
   @callback options(keyword(), URI.t()) :: keyword()
 
+  # AdminFE stores an empty proxy field as "", which means no proxy.
   @spec format_proxy(String.t() | tuple() | nil) :: proxy() | nil
-  def format_proxy(nil), do: nil
+  def format_proxy(proxy) when proxy in [nil, ""], do: nil
 
   def format_proxy(proxy_url) do
     case parse_proxy(proxy_url) do
@@ -32,7 +33,7 @@ defmodule Pleroma.HTTP.AdapterHelper do
   end
 
   @spec maybe_add_proxy(keyword(), proxy() | nil) :: keyword()
-  def maybe_add_proxy(opts, nil), do: opts
+  def maybe_add_proxy(opts, proxy) when proxy in [nil, ""], do: opts
   def maybe_add_proxy(opts, proxy), do: Keyword.put_new(opts, :proxy, proxy)
 
   @doc """

test/pleroma/http/adapter_helper/hackney_test.exs

@@ -58,6 +58,13 @@ defmodule Pleroma.HTTP.AdapterHelper.HackneyTest do
                {:socks5, ~c"::1", 9050}
     end
 
+    # AdminFE stores an empty field as "", and Hackney 4 fails every request with it.
+    test "ignores an empty proxy_url", %{uri: uri} do
+      clear_config([:http, :proxy_url], "")
+
+      refute Keyword.has_key?(Hackney.options([], uri), :proxy)
+    end
+
     test "respect connection opts and no proxy", %{uri: uri} do
       opts = Hackney.options([a: 2, b: 1], uri)
 

test/pleroma/http/adapter_helper_test.exs

@@ -12,6 +12,12 @@ defmodule Pleroma.HTTP.AdapterHelperTest do
       assert AdapterHelper.format_proxy(nil) == nil
     end
 
+    test "with an empty string" do
+      assert ExUnit.CaptureLog.capture_log(fn ->
+               assert AdapterHelper.format_proxy("") == nil
+             end) == ""
+    end
+
     test "with string" do
       assert AdapterHelper.format_proxy("127.0.0.1:8123") == {{127, 0, 0, 1}, 8123}
     end