@@ -225,11 +225,14 @@
  defp handle_fetch(repo, args) do
    wants = extract_shas(args, "want ")
    haves = extract_shas(args, "have ")
    done = Enum.any?(args, &(String.trim(&1) == "done"))
    Logger.info(
      "UploadPackV2.handle_fetch: #{length(wants)} wants, #{length(haves)} haves, done=#{done}"
    )
    Logger.info("UploadPackV2.handle_fetch: #{length(wants)} wants, #{length(haves)} haves")
    # Build acknowledgments section when client sends haves
    ack_section = build_acknowledgments(repo, haves, done)
    ack_section = build_acknowledgments(repo, haves)
    case collect_objects(repo, wants, haves) do
      {:ok, objects} ->
@@ -254,13 +257,13 @@
    end
  end
  defp build_acknowledgments(_repo, []) do
    # No haves = initial clone, no acknowledgments section needed
  defp build_acknowledgments(_repo, [], _done) do
    # No haves = initial clone, no acknowledgments section needed.
    <<>>
  end
  defp build_acknowledgments(repo, haves, done) do
    # Check which haves we have in common.
  defp build_acknowledgments(repo, haves) do
    # Check which haves we have in common
    acks =
      haves
      |> Enum.filter(fn sha ->
@@ -271,16 +274,35 @@
      end)
      |> Enum.map(fn sha -> PktLine.encode("ACK #{sha}") end)
    header = PktLine.encode("acknowledgments")
    # Per protocol v2 (Documentation/technical/protocol-v2.txt):
    #   acknowledgments = PKT-LINE("acknowledgments" LF) (nak | *ack) [ready]
    # and: if the client sent `done` the server MUST be "ready" — either by
    # emitting a `ready` line at the end of the acks section, or by omitting
    # the section entirely. Sending `NAK` followed by a packfile is a
    # protocol violation; real git clients reject it with
    #   fatal: expected no other sections to be sent after no 'ready'
    cond do
      # Client sent `done` but nothing matched — omit the acks section.
      # A packfile will follow unconditionally.
      done and acks == [] ->
        <<>>
      # Client sent `done` — end the acks section with `ready` so the
      # following packfile section is expected by the client.
      done ->
        header = PktLine.encode("acknowledgments")
        IO.iodata_to_binary([header | acks] ++ [PktLine.encode("ready"), PktLine.delim()])
      # Multi-round negotiation: client hasn't sent `done` yet.
      # No matches found — tell the client to send more haves.
      acks == [] ->
        header = PktLine.encode("acknowledgments")
    ack_lines =
      if acks == [] do
        [PktLine.encode("NAK")]
      else
        acks ++ [PktLine.encode("ready")]
      end
        IO.iodata_to_binary([header, PktLine.encode("NAK"), PktLine.flush()])
      true ->
    IO.iodata_to_binary([header | ack_lines] ++ [PktLine.delim()])
        header = PktLine.encode("acknowledgments")
        IO.iodata_to_binary([header | acks] ++ [PktLine.flush()])
    end
  end
  defp extract_shas(args, prefix) do