ethrpc: embed error data in message

Author: attente

ethrpc/jsonrpc/jsonrpc.go

@@ -1,6 +1,7 @@
 package jsonrpc
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 )
@@ -34,5 +35,15 @@ type Error struct {
 
 // Error implements the error interface.
 func (e Error) Error() string {
-	return fmt.Sprintf("jsonrpc error %d: %s", e.Code, e.Message)
+	message := fmt.Sprintf("jsonrpc error %v: %v", e.Code, e.Message)
+	if len(e.Data) == 0 {
+		return message
+	}
+
+	var data bytes.Buffer
+	if err := json.Compact(&data, e.Data); err != nil {
+		return fmt.Sprintf("%v, data: %q", message, string(e.Data))
+	}
+
+	return fmt.Sprintf("%v, data: %v", message, data.String())
 }

ethrpc/jsonrpc/jsonrpc_test.go

@@ -0,0 +1,31 @@
+package jsonrpc
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+func TestErrorString(t *testing.T) {
+	t.Run("without data", func(t *testing.T) {
+		err := Error{
+			Code:    -32000,
+			Message: "header not found",
+		}
+
+		if got, want := err.Error(), "jsonrpc error -32000: header not found"; got != want {
+			t.Fatalf("unexpected error string: got %q, want %q", got, want)
+		}
+	})
+
+	t.Run("with json data", func(t *testing.T) {
+		err := Error{
+			Code:    3,
+			Message: "execution reverted",
+			Data:    json.RawMessage("{\n\t\"reason\": \"bad\",\n\t\"code\": 123\n}"),
+		}
+
+		if got, want := err.Error(), `jsonrpc error 3: execution reverted, data: {"reason":"bad","code":123}`; got != want {
+			t.Fatalf("unexpected error string: got %q, want %q", got, want)
+		}
+	})
+}