improve Unexpected EOF error message

internal/message.go

@@ -4,6 +4,7 @@ package internal
 import (
  "bytes"
  "encoding/binary"
+ "errors"
  "io"
  "net"
 
@@ -84,7 +85,7 @@ func formatExtendedPayload(buf bytes.Buffer, extensionId uint8) []byte {
 }
 
 // Read parses a message from a stream. Returns `nil` on keep-alive message
-func readMessage(r io.Reader) (*Message, error) {
+func readMessage(r io.Reader, logger *logger.Logger) (*Message, error) {
  lengthBuf := make([]byte, 4)
  _, err := io.ReadFull(r, lengthBuf)
  if err != nil {
@@ -100,6 +101,9 @@ func readMessage(r io.Reader) (*Message, error) {
  messageBuf := make([]byte, length)
  _, err = io.ReadFull(r, messageBuf)
  if err != nil {
+ if errors.Is(err, io.ErrUnexpectedEOF) {
+ logger.Errorln("Ensure message length prefix has the correct value. Also make sure you're sending correct sequence of messages.")
+ }
  return nil, err
  }
 

internal/stage_magnet_helpers.go

@@ -173,7 +173,7 @@ func receiveAndAssertExtensionHandshake(conn net.Conn, logger *logger.Logger) (i
 
 func receiveExtensionHandshake(conn net.Conn, logger *logger.Logger) (*Message, error) {
  logger.Debugln("Waiting to receive extension handshake message")
- msg, err := readMessage(conn)
+ msg, err := readMessage(conn, logger)
  if err != nil {
  return nil, err
  }

internal/stage_magnet_metadata1.go

@@ -81,7 +81,7 @@ func readMetadataRequest(conn net.Conn, logger *logger.Logger) (err error) {
  defer logOnExit(logger, &err)
 
  logger.Debugln("Waiting to receive metadata request")
- msg, err := readMessage(conn)
+ msg, err := readMessage(conn, logger)
  if err != nil {
  return fmt.Errorf("error reading message: %v", err.Error())
  }