fix(proxy): align miner success wire format

Co-Authored-By: Virgil <virgil@lethean.io>

miner_login_test.go

@@ -54,6 +54,7 @@ func TestMiner_HandleLogin_Good(t *testing.T) {
 	<-done
 
 	var payload struct {
+		Error  json.RawMessage `json:"error"`
 		Result struct {
 			ID         string         `json:"id"`
 			Status     string         `json:"status"`
@@ -65,6 +66,9 @@ func TestMiner_HandleLogin_Good(t *testing.T) {
 		t.Fatalf("unmarshal login response: %v", err)
 	}
 
+	if string(payload.Error) != "null" {
+		t.Fatalf("expected login response error to be null, got %s", string(payload.Error))
+	}
 	if payload.Result.Status != "OK" {
 		t.Fatalf("expected login success, got %q", payload.Result.Status)
 	}
@@ -293,8 +297,11 @@ func TestMiner_HandleKeepalived_Good(t *testing.T) {
 	if err := json.Unmarshal(line, &payload); err != nil {
 		t.Fatalf("unmarshal keepalived response: %v", err)
 	}
-	if _, ok := payload["error"]; ok {
+	if _, ok := payload["error"]; !ok {
-		t.Fatalf("expected keepalived response to omit error field, got %s", string(line))
+		t.Fatalf("expected keepalived response to include error field, got %s", string(line))
+	}
+	if string(payload["error"]) != "null" {
+		t.Fatalf("expected keepalived response error to be null, got %s", string(payload["error"]))
 	}
 	var result struct {
 		Status string `json:"status"`

miner_wire_test.go

@@ -0,0 +1,43 @@
+package proxy
+
+import (
+	"bufio"
+	"encoding/json"
+	"net"
+	"testing"
+)
+
+func TestMiner_Success_WritesNullError_Good(t *testing.T) {
+	minerConn, clientConn := net.Pipe()
+	defer minerConn.Close()
+	defer clientConn.Close()
+
+	miner := NewMiner(minerConn, 3333, nil)
+	done := make(chan struct{})
+	go func() {
+		miner.Success(7, "OK")
+		close(done)
+	}()
+
+	line, err := bufio.NewReader(clientConn).ReadBytes('\n')
+	if err != nil {
+		t.Fatalf("read success response: %v", err)
+	}
+	<-done
+
+	var payload struct {
+		Error  json.RawMessage `json:"error"`
+		Result struct {
+			Status string `json:"status"`
+		} `json:"result"`
+	}
+	if err := json.Unmarshal(line, &payload); err != nil {
+		t.Fatalf("unmarshal success response: %v", err)
+	}
+	if string(payload.Error) != "null" {
+		t.Fatalf("expected success response error to be null, got %s", string(payload.Error))
+	}
+	if payload.Result.Status != "OK" {
+		t.Fatalf("expected success status OK, got %q", payload.Result.Status)
+	}
+}

state_impl.go

@@ -1086,6 +1086,7 @@ func (m *Miner) replyLoginSuccess(id int64) {
 	payload := map[string]any{
 		"id":      id,
 		"jsonrpc": "2.0",
+		"error":   nil,
 		"result":  result,
 	}
 	_ = m.writeJSON(payload)
@@ -1133,6 +1134,7 @@ func (m *Miner) Success(id int64, status string) {
 	payload := map[string]any{
 		"id":      id,
 		"jsonrpc": "2.0",
+		"error":   nil,
 		"result": map[string]any{
 			"status": status,
 		},