Fix dominikh/go-tools nits (#758)

* Remove unused functions and consts

* Address gosimple nits

* Address staticcheck nits

This excludes several that were intentional or weren't actual errors.

* Reduce size of lex struct

This reduces the size of the lex struct by 8 bytes from:
  lex.token string: 0-16 (size 16, align 8)
  lex.tokenUpper string: 16-32 (size 16, align 8)
  lex.length int: 32-40 (size 8, align 8)
  lex.err bool: 40-41 (size 1, align 1)
  lex.value uint8: 41-42 (size 1, align 1)
  padding: 42-48 (size 6, align 0)
  lex.line int: 48-56 (size 8, align 8)
  lex.column int: 56-64 (size 8, align 8)
  lex.torc uint16: 64-66 (size 2, align 2)
  padding: 66-72 (size 6, align 0)
  lex.comment string: 72-88 (size 16, align 8)
to:
  lex.token string: 0-16 (size 16, align 8)
  lex.tokenUpper string: 16-32 (size 16, align 8)
  lex.length int: 32-40 (size 8, align 8)
  lex.err bool: 40-41 (size 1, align 1)
  lex.value uint8: 41-42 (size 1, align 1)
  lex.torc uint16: 42-44 (size 2, align 2)
  padding: 44-48 (size 4, align 0)
  lex.line int: 48-56 (size 8, align 8)
  lex.column int: 56-64 (size 8, align 8)
  lex.comment string: 64-80 (size 16, align 8)

* Reduce size of response struct

This reduces the size of the response struct by 8 bytes from:
  response.msg []byte: 0-24 (size 24, align 8)
  response.hijacked bool: 24-25 (size 1, align 1)
  padding: 25-32 (size 7, align 0)
  response.tsigStatus error: 32-48 (size 16, align 8)
  response.tsigTimersOnly bool: 48-49 (size 1, align 1)
  padding: 49-56 (size 7, align 0)
  response.tsigRequestMAC string: 56-72 (size 16, align 8)
  response.tsigSecret map[string]string: 72-80 (size 8, align 8)
  response.udp *net.UDPConn: 80-88 (size 8, align 8)
  response.tcp net.Conn: 88-104 (size 16, align 8)
  response.udpSession *github.com/tmthrgd/dns.SessionUDP: 104-112 (size 8, align 8)
  response.writer github.com/tmthrgd/dns.Writer: 112-128 (size 16, align 8)
  response.wg *sync.WaitGroup: 128-136 (size 8, align 8)
to:
  response.msg []byte: 0-24 (size 24, align 8)
  response.hijacked bool: 24-25 (size 1, align 1)
  response.tsigTimersOnly bool: 25-26 (size 1, align 1)
  padding: 26-32 (size 6, align 0)
  response.tsigStatus error: 32-48 (size 16, align 8)
  response.tsigRequestMAC string: 48-64 (size 16, align 8)
  response.tsigSecret map[string]string: 64-72 (size 8, align 8)
  response.udp *net.UDPConn: 72-80 (size 8, align 8)
  response.tcp net.Conn: 80-96 (size 16, align 8)
  response.udpSession *github.com/tmthrgd/dns.SessionUDP: 96-104 (size 8, align 8)
  response.writer github.com/tmthrgd/dns.Writer: 104-120 (size 16, align 8)
  response.wg *sync.WaitGroup: 120-128 (size 8, align 8)

client.go

@@ -567,7 +567,7 @@ func (c *Client) ExchangeContext(ctx context.Context, m *Msg, a string) (r *Msg,
 	if deadline, ok := ctx.Deadline(); !ok {
 		timeout = 0
 	} else {
-		timeout = deadline.Sub(time.Now())
+		timeout = time.Until(deadline)
 	}
 	// not passing the context to the underlying calls, as the API does not support
 	// context. For timeouts you should set up Client.Dialer and call Client.Exchange.

dns_test.go

@@ -10,8 +10,7 @@ import (
 func TestPackUnpack(t *testing.T) {
 	out := new(Msg)
 	out.Answer = make([]RR, 1)
-	key := new(DNSKEY)
-	key = &DNSKEY{Flags: 257, Protocol: 3, Algorithm: RSASHA1}
+	key := &DNSKEY{Flags: 257, Protocol: 3, Algorithm: RSASHA1}
 	key.Hdr = RR_Header{Name: "miek.nl.", Rrtype: TypeDNSKEY, Class: ClassINET, Ttl: 3600}
 	key.PublicKey = "AwEAAaHIwpx3w4VHKi6i1LHnTaWeHCL154Jug0Rtc9ji5qwPXpBo6A5sRv7cSsPQKPIwxLpyCrbJ4mr2L0EPOdvP6z6YfljK2ZmTbogU9aSU2fiq/4wjxbdkLyoDVgtO+JsxNN4bjr4WcWhsmk1Hg93FV9ZpkWb0Tbad8DFqNDzr//kZ"
 
@@ -25,8 +24,7 @@ func TestPackUnpack(t *testing.T) {
 		t.Error("failed to unpack msg with DNSKEY")
 	}
 
-	sig := new(RRSIG)
-	sig = &RRSIG{TypeCovered: TypeDNSKEY, Algorithm: RSASHA1, Labels: 2,
+	sig := &RRSIG{TypeCovered: TypeDNSKEY, Algorithm: RSASHA1, Labels: 2,
 		OrigTtl: 3600, Expiration: 4000, Inception: 4000, KeyTag: 34641, SignerName: "miek.nl.",
 		Signature: "AwEAAaHIwpx3w4VHKi6i1LHnTaWeHCL154Jug0Rtc9ji5qwPXpBo6A5sRv7cSsPQKPIwxLpyCrbJ4mr2L0EPOdvP6z6YfljK2ZmTbogU9aSU2fiq/4wjxbdkLyoDVgtO+JsxNN4bjr4WcWhsmk1Hg93FV9ZpkWb0Tbad8DFqNDzr//kZ"}
 	sig.Hdr = RR_Header{Name: "miek.nl.", Rrtype: TypeRRSIG, Class: ClassINET, Ttl: 3600}
@@ -293,7 +291,7 @@ func TestTKEY(t *testing.T) {
 	if offset != len(tkeyBytes) {
 		t.Fatalf("mismatched TKEY RR size %d != %d", len(tkeyBytes), offset)
 	}
-	if bytes.Compare(tkeyBytes, msg[0:offset]) != 0 {
+	if !bytes.Equal(tkeyBytes, msg[0:offset]) {
 		t.Fatal("mismatched TKEY data after rewriting bytes")
 	}
 

dnssec_test.go

@@ -12,18 +12,6 @@ import (
 	"golang.org/x/crypto/ed25519"
 )
 
-func getKey() *DNSKEY {
-	key := new(DNSKEY)
-	key.Hdr.Name = "miek.nl."
-	key.Hdr.Class = ClassINET
-	key.Hdr.Ttl = 14400
-	key.Flags = 256
-	key.Protocol = 3
-	key.Algorithm = RSASHA256
-	key.PublicKey = "AwEAAcNEU67LJI5GEgF9QLNqLO1SMq1EdoQ6E9f85ha0k0ewQGCblyW2836GiVsm6k8Kr5ECIoMJ6fZWf3CQSQ9ycWfTyOHfmI3eQ/1Covhb2y4bAmL/07PhrL7ozWBW3wBfM335Ft9xjtXHPy7ztCbV9qZ4TVDTW/Iyg0PiwgoXVesz"
-	return key
-}
-
 func getSoa() *SOA {
 	soa := new(SOA)
 	soa.Hdr = RR_Header{"miek.nl.", TypeSOA, ClassINET, 14400, 0}

msg.go

@@ -367,12 +367,10 @@ Loop:
 						var buf [3]byte
 						bufs := strconv.AppendInt(buf[:0], int64(b), 10)
 						s = append(s, '\\')
-						for i := 0; i < 3-len(bufs); i++ {
+						for i := len(bufs); i < 3; i++ {
 							s = append(s, '0')
 						}
-						for _, r := range bufs {
-							s = append(s, r)
-						}
+						s = append(s, bufs...)
 						// presentation-format \DDD escapes add 3 extra bytes
 						maxLen += 3
 					} else {

msg_test.go

@@ -8,10 +8,7 @@ import (
 	"testing"
 )
 
-const (
-	maxPrintableLabel = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789x"
-	tooLongLabel      = maxPrintableLabel + "x"
-)
+const maxPrintableLabel = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789x"
 
 var (
 	longDomain = maxPrintableLabel[:53] + strings.TrimSuffix(

privaterr.go

@@ -134,7 +134,7 @@ func PrivateHandle(rtypestr string, rtype uint16, generator func() PrivateRdata)
 	typeToparserFunc[rtype] = parserFunc{setPrivateRR, true}
 }
 
-// PrivateHandleRemove removes defenitions required to support private RR type.
+// PrivateHandleRemove removes definitions required to support private RR type.
 func PrivateHandleRemove(rtype uint16) {
 	rtypestr, ok := TypeToString[rtype]
 	if ok {
@@ -144,5 +144,4 @@ func PrivateHandleRemove(rtype uint16) {
 		delete(StringToType, rtypestr)
 		delete(typeToUnpack, rtype)
 	}
-	return
 }

scan.go

@@ -10,7 +10,6 @@ import (
 )
 
 const maxTok = 2048 // Largest token we can return.
-const maxUint16 = 1<<16 - 1
 
 // Tokinize a RFC 1035 zone file. The tokenizer will normalize it:
 // * Add ownernames if they are left blank;
@@ -80,9 +79,9 @@ type lex struct {
 	length     int    // length of the token
 	err        bool   // when true, token text has lexer error
 	value      uint8  // value: zString, _BLANK, etc.
+	torc       uint16 // type or class as parsed in the lexer, we only need to look this up in the grammar
 	line       int    // line in the file
 	column     int    // column in the file
-	torc       uint16 // type or class as parsed in the lexer, we only need to look this up in the grammar
 	comment    string // any comment text seen
 }
 
@@ -209,10 +208,9 @@ func parseZone(r io.Reader, origin, f string, defttl *ttlState, t chan *Token, i
 	var prevName string
 	for l := range c {
 		// Lexer spotted an error already
-		if l.err == true {
+		if l.err {
 			t <- &Token{Error: &ParseError{f, l.token, l}}
 			return
-
 		}
 		switch st {
 		case zExpectOwnerDir:
@@ -639,7 +637,6 @@ func zlexer(s *scan, c chan lex) {
 			if quote {
 				str[stri] = x
 				stri++
-				break
 			}
 			// discard if outside of quotes
 		case '\n':

scanner.go

@@ -42,7 +42,7 @@ func (s *scan) tokenText() (byte, error) {
 
 	// delay the newline handling until the next token is delivered,
 	// fixes off-by-one errors when reporting a parse error.
-	if s.eof == true {
+	if s.eof {
 		s.position.Line++
 		s.position.Column = 0
 		s.eof = false

server.go

@@ -83,8 +83,8 @@ type ConnectionStater interface {
 type response struct {
 	msg            []byte
 	hijacked       bool // connection has been hijacked by handler
-	tsigStatus     error
 	tsigTimersOnly bool
+	tsigStatus     error
 	tsigRequestMAC string
 	tsigSecret     map[string]string // the tsig secrets
 	udp            *net.UDPConn      // i/o connection if UDP was used

sig0.go

@@ -127,8 +127,7 @@ func (rr *SIG) Verify(k *KEY, buf []byte) error {
 		if offset+1 >= buflen {
 			continue
 		}
-		var rdlen uint16
-		rdlen = binary.BigEndian.Uint16(buf[offset:])
+		rdlen := binary.BigEndian.Uint16(buf[offset:])
 		offset += 2
 		offset += int(rdlen)
 	}

udp_test.go

@@ -33,7 +33,8 @@ func TestSetUDPSocketOptions(t *testing.T) {
 			b := make([]byte, 1)
 			_, sess, err := ReadFromSessionUDP(c, b)
 			if err != nil {
-				t.Fatalf("failed to read from conn: %v", err)
+				t.Errorf("failed to read from conn: %v", err)
+				// fallthrough to chan send below
 			}
 			ch <- sess
 		}()
@@ -46,6 +47,10 @@ func TestSetUDPSocketOptions(t *testing.T) {
 			t.Fatalf("failed to write to conn: %v", err)
 		}
 		sess := <-ch
+		if sess == nil {
+			// t.Error was already called in the goroutine above.
+			t.FailNow()
+		}
 		if len(sess.context) == 0 {
 			t.Fatalf("empty session context: %v", sess)
 		}