Use a consistent format for errors

Author: guelfey

auth.go

@@ -72,7 +72,7 @@ func (conn *Conn) Auth(methods []Auth) error {
 		return err
 	}
 	if len(s) < 2 || !bytes.Equal(s[0], []byte("REJECTED")) {
-		return errors.New("authentication protocol error")
+		return errors.New("dbus: authentication protocol error")
 	}
 	s = s[1:]
 	for _, v := range s {
@@ -89,7 +89,7 @@ func (conn *Conn) Auth(methods []Auth) error {
 				case AuthContinue:
 					err, ok = conn.tryAuth(m, waitingForData, in)
 				default:
-					panic("invalid authentication status")
+					panic("dbus: invalid authentication status")
 				}
 				if err != nil {
 					return err
@@ -110,7 +110,7 @@ func (conn *Conn) Auth(methods []Auth) error {
 							conn.unixFD = true
 						case bytes.Equal(line[0], []byte("ERROR")):
 						default:
-							return errors.New("authentication protocol error")
+							return errors.New("dbus: authentication protocol error")
 						}
 					}
 					err = authWriteLine(conn.transport, []byte("BEGIN"))
@@ -125,7 +125,7 @@ func (conn *Conn) Auth(methods []Auth) error {
 			}
 		}
 	}
-	return errors.New("authentication failed")
+	return errors.New("dbus: authentication failed")
 }
 
 // tryAuth tries to authenticate with m as the mechanism, using state as the
@@ -216,9 +216,9 @@ func (conn *Conn) tryAuth(m Auth, state authState, in *bufio.Reader) (error, boo
 		case state == waitingForReject && string(s[0]) == "REJECTED":
 			return nil, false
 		case state == waitingForReject:
-			return errors.New("authentication protocol error"), false
+			return errors.New("dbus: authentication protocol error"), false
 		default:
-			panic("invalid auth state")
+			panic("dbus: invalid auth state")
 		}
 	}
 }

call.go

@@ -24,7 +24,7 @@ type Call struct {
 	Body []interface{}
 }
 
-var errSignature = errors.New("mismatched signature")
+var errSignature = errors.New("dbus: mismatched signature")
 
 // Store stores the body of the reply into the provided pointers. It returns
 // an error if the signatures of the body and retvalues don't match, or if
@@ -85,7 +85,7 @@ func (o *Object) Go(method string, flags Flags, ch chan *Call, args ...interface
 		if ch == nil {
 			ch = make(chan *Call, 10)
 		} else if cap(ch) == 0 {
-			panic("(*dbus.Object).Go: unbuffered channel")
+			panic("dbus: unbuffered channel passed to (*Object).Go")
 		}
 		call := &Call{
 			Destination: o.dest,

conn.go

@@ -21,7 +21,7 @@ var (
 )
 
 // ErrClosed is the error returned by calls on a closed connection.
-var ErrClosed = errors.New("closed by user")
+var ErrClosed = errors.New("dbus: connection closed by user")
 
 // Conn represents a connection to a message bus (usually, the system or
 // session bus).
@@ -101,7 +101,7 @@ func SessionBusPrivate() (*Conn, error) {
 	i := bytes.IndexByte(b, '=')
 	j := bytes.IndexByte(b, '\n')
 	if i == -1 || j == -1 {
-		return nil, errors.New("couldn't determine address of the session bus")
+		return nil, errors.New("dbus: couldn't determine address of session bus")
 	}
 	return Dial(string(b[i+1 : j]))
 }
@@ -383,7 +383,7 @@ func (conn *Conn) Send(msg *Message, ch chan *Call) *Call {
 		if ch == nil {
 			ch = make(chan *Call, 5)
 		} else if cap(ch) == 0 {
-			panic("(*dbus.Conn).Send: unbuffered channel")
+			panic("dbus: unbuffered channel passed to (*Conn).Send")
 		}
 		call = new(Call)
 		call.Destination, _ = msg.Headers[FieldDestination].value.(string)
@@ -558,12 +558,12 @@ func getTransport(address string) (transport, error) {
 	for _, v := range addresses {
 		i := strings.IndexRune(v, ':')
 		if i == -1 {
-			err = errors.New("bad address: no transport")
+			err = errors.New("dbus: invalid bus address (no transport)")
 			continue
 		}
 		f := m[v[:i]]
 		if f == nil {
-			err = errors.New("bad address: invalid or unsupported transport")
+			err = errors.New("dbus: invalid bus address (invalid or unsupported transport)")
 		}
 		t, err = f(v[i+1:])
 		if err == nil {

dbus.go

@@ -32,8 +32,8 @@ type InvalidTypeError struct {
 	Type reflect.Type
 }
 
-func (err InvalidTypeError) Error() string {
-	return "dbus: invalid type " + err.Type.String()
+func (e InvalidTypeError) Error() string {
+	return "dbus: invalid type " + e.Type.String()
 }
 
 // Store copies the values contained in src to dest, which must be a slice of

decoder.go

@@ -61,7 +61,7 @@ func (dec *Decoder) Decode(vs ...interface{}) (err error) {
 		var ok bool
 		if err, ok = recover().(error); ok {
 			if err == io.EOF || err == io.ErrUnexpectedEOF {
-				err = FormatError("input too short (unexpected EOF)")
+				err = FormatError("unexpected EOF")
 			}
 		}
 	}()
@@ -261,5 +261,5 @@ func (dec *Decoder) decode(v reflect.Value, depth int) {
 type FormatError string
 
 func (e FormatError) Error() string {
-	return "dbus format error: " + string(e)
+	return "dbus: wire format error: " + string(e)
 }

export.go

@@ -139,19 +139,19 @@ func (conn *Conn) handleCall(msg *Message) {
 // formatted as "interface.member", e.g., "org.freedesktop.DBus.NameLost".
 func (conn *Conn) Emit(path ObjectPath, name string, values ...interface{}) error {
 	if !path.IsValid() {
-		return errors.New("invalid object path")
+		return errors.New("dbus: invalid object path")
 	}
 	i := strings.LastIndex(name, ".")
 	if i == -1 {
-		return errors.New("invalid method name")
+		return errors.New("dbus: invalid method name")
 	}
 	iface := name[:i]
 	member := name[i+1:]
 	if !isValidMember(member) {
-		return errors.New("invalid method name")
+		return errors.New("dbus: invalid method name")
 	}
 	if !isValidInterface(iface) {
-		return errors.New("invalid interface name")
+		return errors.New("dbus: invalid interface name")
 	}
 	msg := new(Message)
 	msg.Type = TypeSignal
@@ -191,7 +191,7 @@ func (conn *Conn) Emit(path ObjectPath, name string, values ...interface{}) erro
 // Export returns an error if path is not a valid path name.
 func (conn *Conn) Export(v interface{}, path ObjectPath, iface string) error {
 	if !path.IsValid() {
-		return errors.New("invalid path name")
+		return errors.New("dbus: invalid path name")
 	}
 	conn.handlersLck.Lock()
 	if _, ok := conn.handlers[path]; !ok {

message.go

@@ -58,7 +58,7 @@ const (
 type InvalidMessageError string
 
 func (e InvalidMessageError) Error() string {
-	return "invalid message: " + string(e)
+	return "dbus: invalid message: " + string(e)
 }
 
 // fieldType are the types of the various header fields.

sig.go

@@ -1,6 +1,7 @@
 package dbus
 
 import (
+	"fmt"
 	"reflect"
 	"strings"
 )
@@ -168,8 +169,8 @@ type SignatureError struct {
 	Reason string
 }
 
-func (err SignatureError) Error() string {
-	return "dbus: invalid signature: '" + err.Sig + "' (" + err.Reason + ")"
+func (e SignatureError) Error() string {
+	return fmt.Sprintf("dbus: invalid signature: %q (%s)", e.Sig, e.Reason)
 }
 
 // Try to read a single type from this string. If it was successfull, err is nil

transport_generic.go

@@ -28,7 +28,7 @@ func (t genericTransport) ReadMessage() (*Message, error) {
 func (t genericTransport) SendMessage(msg *Message) error {
 	for _, v := range msg.Body {
 		if _, ok := v.(UnixFD); ok {
-			return errors.New("unix fd passing not enabled")
+			return errors.New("dbus: unix fd passing not enabled")
 		}
 	}
 	return msg.EncodeTo(t, binary.LittleEndian)

transport_unix.go

@@ -22,7 +22,7 @@ func (o *oobReader) Read(b []byte) (n int, err error) {
 		return n, err
 	}
 	if flags&syscall.MSG_CTRUNC != 0 {
-		return n, errors.New("control data truncated (too many fds received)")
+		return n, errors.New("dbus: control data truncated (too many fds received)")
 	}
 	o.oob = append(o.oob, o.buf[:oobn]...)
 	return n, nil
@@ -41,7 +41,7 @@ func newUnixTransport(keys string) (transport, error) {
 	path := getKey(keys, "path")
 	switch {
 	case abstract == "" && path == "":
-		return nil, errors.New("bad address: neither path nor abstract set")
+		return nil, errors.New("dbus: invalid address (neither path nor abstract set)")
 	case abstract != "" && path == "":
 		t.UnixConn, err = net.DialUnix("unix", nil, &net.UnixAddr{Name: "@" + abstract, Net: "unix"})
 		if err != nil {
@@ -54,10 +54,9 @@ func newUnixTransport(keys string) (transport, error) {
 			return nil, err
 		}
 		return t, nil
-	case abstract != "" && path != "":
-		return nil, errors.New("bad address: both path and abstract set")
+	default:
+		return nil, errors.New("dbus: invalid address (both path and abstract set)")
 	}
-	panic("not reached")
 }
 
 func (t *unixTransport) EnableUnixFDs() {
@@ -121,15 +120,15 @@ func (t *unixTransport) ReadMessage() (*Message, error) {
 	}
 	if unixfds != 0 {
 		if !t.hasUnixFDs {
-			return nil, errors.New("got unix fds on unsupported transport")
+			return nil, errors.New("dbus: got unix fds on unsupported transport")
 		}
 		// read the fds from the OOB data
 		scms, err := syscall.ParseSocketControlMessage(rd.oob)
 		if err != nil {
 			return nil, err
 		}
 		if len(scms) != 1 {
-			return nil, errors.New("invalid number of SCM's received")
+			return nil, errors.New("dbus: received more than one socket control message")
 		}
 		fds, err := syscall.ParseUnixRights(&scms[0])
 		if err != nil {
@@ -164,7 +163,7 @@ func (t *unixTransport) SendMessage(msg *Message) error {
 	}
 	if len(fds) != 0 {
 		if !t.hasUnixFDs {
-			return errors.New("unix fd passing not enabled")
+			return errors.New("dbus: unix fd passing not enabled")
 		}
 		msg.Headers[FieldUnixFDs] = MakeVariant(uint32(len(fds)))
 		oob := syscall.UnixRights(fds...)