enable errcheck (#65)

.golangci.yml

@@ -15,13 +15,46 @@ linters:
   - unconvert
   - wastedassign
   - whitespace
-  disable:
-  - errcheck
 
 issues:
   exclude-use-default: false
 
 linters-settings:
+  errcheck:
+    exclude-functions:
+    - io.Copy
+    - (io.Closer).Close
+    - (io.Writer).Write
+    - (hash.Hash).Write
+    - (net.Conn).Close
+    - (net.Conn).SetReadDeadline
+    - (net.Conn).SetWriteDeadline
+    - (*net.TCPConn).SetKeepAlive
+    - (*net.TCPConn).SetKeepAlivePeriod
+    - (*net.TCPConn).SetNoDelay
+    - (net.Listener).Close
+    - (net.PacketConn).Close
+    - (net.PacketConn).SetReadDeadline
+    - (net.PacketConn).SetWriteDeadline
+    - (net/http.ResponseWriter).Write
+    - (*net/http.Server).Serve
+    - (*net/http.Server).ServeTLS
+    - (*net/http.Server).Shutdown
+    - os.Chdir
+    - os.Mkdir
+    - os.MkdirAll
+    - os.Remove
+    - os.RemoveAll
+    - os.Setenv
+    - os.Unsetenv
+    - (*os.File).WriteString
+    - (*os.File).Close
+    - (github.com/datarhei/gosrt.Conn).Close
+    - (github.com/datarhei/gosrt.Conn).SetReadDeadline
+    - (github.com/datarhei/gosrt.Conn).SetWriteDeadline
+    - (*github.com/bluenviron/gortsplib/v3.Client).Close
+    - (*github.com/bluenviron/gortsplib/v3.Server).Close
+
   govet:
     enable-all: true
     disable:

channel.go

@@ -8,10 +8,10 @@ import (
 	"github.com/bluenviron/gomavlib/v2/pkg/message"
 )
 
-func randomByte() byte {
+func randomByte() (byte, error) {
 	var buf [1]byte
-	rand.Read(buf[:])
-	return buf[0]
+	_, err := rand.Read(buf[:])
+	return buf[0], err
 }
 
 // Channel is a communication channel created by an Endpoint.
@@ -32,6 +32,11 @@ type Channel struct {
 }
 
 func newChannel(n *Node, e Endpoint, label string, rwc io.ReadWriteCloser) (*Channel, error) {
+	linkID, err := randomByte()
+	if err != nil {
+		return nil, err
+	}
+
 	frw, err := frame.NewReadWriter(frame.ReadWriterConf{
 		ReadWriter:  rwc,
 		DialectRW:   n.dialectRW,
@@ -44,7 +49,7 @@ func newChannel(n *Node, e Endpoint, label string, rwc io.ReadWriteCloser) (*Cha
 			return frame.V1
 		}(),
 		OutComponentID:     n.conf.OutComponentID,
-		OutSignatureLinkID: randomByte(),
+		OutSignatureLinkID: linkID,
 		OutKey:             n.conf.OutKey,
 	})
 	if err != nil {
@@ -124,10 +129,10 @@ func (ch *Channel) run() {
 		for what := range ch.write {
 			switch wh := what.(type) {
 			case message.Message:
-				ch.frw.WriteMessage(wh)
+				ch.frw.WriteMessage(wh) //nolint:errcheck
 
 			case frame.Frame:
-				ch.frw.WriteFrame(wh)
+				ch.frw.WriteFrame(wh) //nolint:errcheck
 			}
 		}
 	}()

endpoint.go

@@ -31,6 +31,6 @@ type endpointChannelSingle interface {
 // endpointChannelAccepter is an endpoint that provides multiple channels.
 type endpointChannelAccepter interface {
 	Endpoint
-	close() error
+	close()
 	accept() (string, io.ReadWriteCloser, error)
 }

endpoint_server.go

@@ -108,10 +108,9 @@ func (t *endpointServer) Conf() EndpointConf {
 	return t.conf
 }
 
-func (t *endpointServer) close() error {
+func (t *endpointServer) close() {
 	close(t.terminate)
 	t.listener.Close()
-	return nil
 }
 
 func (t *endpointServer) accept() (string, io.ReadWriteCloser, error) {

pkg/autoreconnector/auto_reconnector_test.go

@@ -60,9 +60,9 @@ func TestCloseWhileWorking(t *testing.T) {
 
 				b := make([]byte, 1)
 				if ca == "read" {
-					conn.Read(b)
+					conn.Read(b) //nolint:errcheck
 				} else {
-					conn.Write(b)
+					conn.Write(b) //nolint:errcheck
 				}
 
 				conn.Close()
@@ -82,9 +82,9 @@ func TestCloseWhileWorking(t *testing.T) {
 
 				p := make([]byte, 1)
 				if ca == "read" {
-					a.Read(p)
+					a.Read(p) //nolint:errcheck
 				} else {
-					a.Write(p)
+					a.Write(p) //nolint:errcheck
 				}
 			}()
 

pkg/frame/v1frame.go

@@ -15,6 +15,15 @@ const (
 	V1MagicByte = 0xFE
 )
 
+func peekAndDiscard(br *bufio.Reader, size int) ([]byte, error) {
+	buf, err := br.Peek(size)
+	if err != nil {
+		return nil, err
+	}
+	br.Discard(size) //nolint:errcheck
+	return buf, nil
+}
+
 // V1Frame is a Mavlink V1 frame.
 type V1Frame struct {
 	SequenceID  byte
@@ -63,11 +72,10 @@ func (f V1Frame) GenerateChecksum(crcExtra byte) uint16 {
 
 func (f *V1Frame) decode(br *bufio.Reader) error {
 	// header
-	buf, err := br.Peek(5)
+	buf, err := peekAndDiscard(br, 5)
 	if err != nil {
 		return err
 	}
-	br.Discard(5)
 	msgLen := buf[0]
 	f.SequenceID = buf[1]
 	f.SystemID = buf[2]
@@ -89,11 +97,10 @@ func (f *V1Frame) decode(br *bufio.Reader) error {
 	}
 
 	// checksum
-	buf, err = br.Peek(2)
+	buf, err = peekAndDiscard(br, 2)
 	if err != nil {
 		return err
 	}
-	br.Discard(2)
 	f.Checksum = binary.LittleEndian.Uint16(buf)
 
 	return nil

pkg/frame/v2frame.go

@@ -149,11 +149,10 @@ func (f V2Frame) GenerateSignature(key *V2Key) *V2Signature {
 
 func (f *V2Frame) decode(br *bufio.Reader) error {
 	// header
-	buf, err := br.Peek(9)
+	buf, err := peekAndDiscard(br, 9)
 	if err != nil {
 		return err
 	}
-	br.Discard(9)
 	msgLen := buf[0]
 	f.IncompatibilityFlag = buf[1]
 	f.CompatibilityFlag = buf[2]
@@ -182,20 +181,18 @@ func (f *V2Frame) decode(br *bufio.Reader) error {
 	}
 
 	// checksum
-	buf, err = br.Peek(2)
+	buf, err = peekAndDiscard(br, 2)
 	if err != nil {
 		return err
 	}
-	br.Discard(2)
 	f.Checksum = binary.LittleEndian.Uint16(buf)
 
 	// signature
 	if f.IsSigned() {
-		buf, err := br.Peek(13)
+		buf, err := peekAndDiscard(br, 13)
 		if err != nil {
 			return err
 		}
-		br.Discard(13)
 		f.SignatureLinkID = buf[0]
 		f.SignatureTimestamp = uint48Decode(buf[1:])
 		f.Signature = new(V2Signature)

pkg/x25/x25.go

@@ -31,18 +31,17 @@ func (x *X25) BlockSize() int {
 	return 1
 }
 
-// Write adds more data to the running hash.
-func (x *X25) Write(p []byte) (int, error) {
+// Write adds more data to the hash.
+func (x *X25) Write(p []byte) {
 	for _, b := range p {
 		tmp := uint16(b) ^ (x.crc & 0xFF)
 		tmp ^= (tmp << 4)
 		tmp &= 0xFF
 		x.crc = (x.crc >> 8) ^ (tmp << 8) ^ (tmp << 3) ^ (tmp >> 4)
 	}
-	return len(p), nil
 }
 
-// Sum16 returns the curren thash.
+// Sum16 returns the current hash.
 func (x *X25) Sum16() uint16 {
 	return x.crc
 }