max_body_size -> max_body_length, as it should be

lib/pleroma/reverse_proxy/reverse_proxy.ex

@@ -109,7 +109,7 @@ def call(conn = %{method: method}, url, opts) when method in @methods do
       end
 
     with {:ok, code, headers, client} <- request(method, url, req_headers, hackney_opts),
-         :ok <- header_length_constraint(headers, Keyword.get(opts, :max_body_length)) do
+         :ok <- header_length_constraint(headers, Keyword.get(opts, :max_body_length, @max_body_length)) do
       response(conn, client, url, code, headers, opts)
     else
       {:ok, code, headers} ->
@@ -200,7 +200,7 @@ defp chunk_reply(conn, client, opts, sent_so_far, duration) do
          {:ok, data} <- client().stream_body(client),
          {:ok, duration} <- increase_read_duration(duration),
          sent_so_far = sent_so_far + byte_size(data),
-         :ok <- body_size_constraint(sent_so_far, Keyword.get(opts, :max_body_size)),
+         :ok <- body_size_constraint(sent_so_far, Keyword.get(opts, :max_body_length, @max_body_length)),
          {:ok, conn} <- chunk(conn, data) do
       chunk_reply(conn, client, opts, sent_so_far, duration)
     else

test/reverse_proxy_test.exs

@@ -108,11 +108,11 @@ defp stream_mock(invokes, with_close? \\ false) do
       end
     end
 
-    test "max_body_size returns error if streaming body more than that option", %{conn: conn} do
+    test "max_body_length returns error if streaming body more than that option", %{conn: conn} do
       stream_mock(3, true)
 
       assert capture_log(fn ->
-               ReverseProxy.call(conn, "/stream-bytes/50", max_body_size: 30)
+               ReverseProxy.call(conn, "/stream-bytes/50", max_body_length: 30)
              end) =~
                "[warn] Elixir.Pleroma.ReverseProxy request to /stream-bytes/50 failed while reading/chunking: :body_too_large"
     end