From 1fe04af5230d2fd309d4abd46335876d1fb83ef3 Mon Sep 17 00:00:00 2001
From: mzz2017 <2017@duck.com>
Date: Sun, 27 Aug 2023 11:42:07 +0800
Subject: [PATCH] chore: normalize error names

---
 common/netutils/dns.go                        |  8 ++---
 component/dns/dns.go                          |  6 ++--
 component/dns/upstream.go                     |  4 +--
 component/outbound/dialer_group.go            | 10 +++---
 component/sniffing/http.go                    |  8 ++---
 .../sniffing/internal/quicutils/relocation.go |  8 ++---
 component/sniffing/quic.go                    | 32 +++++++++----------
 component/sniffing/sniffer.go                 | 10 +++---
 component/sniffing/sniffing.go                |  6 ++--
 component/sniffing/tls.go                     | 30 ++++++++---------
 config/config_merger.go                       |  6 ++--
 control/dns_control.go                        |  2 +-
 12 files changed, 65 insertions(+), 65 deletions(-)

diff --git a/common/netutils/dns.go b/common/netutils/dns.go
index fe73299..621a094 100644
--- a/common/netutils/dns.go
+++ b/common/netutils/dns.go
@@ -27,7 +27,7 @@ var (
 	systemDns                netip.AddrPort
 	systemDnsNextUpdateAfter time.Time
 
-	BadDnsAnsError = fmt.Errorf("bad dns answer")
+	ErrBadDnsAns = fmt.Errorf("bad dns answer")
 
 	BootstrapDns = netip.MustParseAddrPort("208.67.222.222:5353")
 )
@@ -107,13 +107,13 @@ func ResolveNetip(ctx context.Context, d netproxy.Dialer, dns netip.AddrPort, ho
 		case dnsmessage.TypeA:
 			a, ok := ans.(*dnsmessage.A)
 			if !ok {
-				return nil, BadDnsAnsError
+				return nil, ErrBadDnsAns
 			}
 			ip, okk = netip.AddrFromSlice(a.A)
 		case dnsmessage.TypeAAAA:
 			a, ok := ans.(*dnsmessage.AAAA)
 			if !ok {
-				return nil, BadDnsAnsError
+				return nil, ErrBadDnsAns
 			}
 			ip, okk = netip.AddrFromSlice(a.AAAA)
 		}
@@ -137,7 +137,7 @@ func ResolveNS(ctx context.Context, d netproxy.Dialer, dns netip.AddrPort, host
 		}
 		ns, ok := ans.(*dnsmessage.NS)
 		if !ok {
-			return nil, BadDnsAnsError
+			return nil, ErrBadDnsAns
 		}
 		records = append(records, ns.Ns)
 	}
diff --git a/component/dns/dns.go b/component/dns/dns.go
index f1ed9d5..6a2951e 100644
--- a/component/dns/dns.go
+++ b/component/dns/dns.go
@@ -20,7 +20,7 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-var BadUpstreamFormatError = fmt.Errorf("bad upstream format")
+var ErrBadUpstreamFormat = fmt.Errorf("bad upstream format")
 
 type Dns struct {
 	log              *logrus.Logger
@@ -55,12 +55,12 @@ func New(dns *config.Dns, opt *NewOption) (s *Dns, err error) {
 
 		tag, link := common.GetTagFromLinkLikePlaintext(string(upstreamRaw))
 		if tag == "" {
-			return nil, fmt.Errorf("%w: '%v' has no tag", BadUpstreamFormatError, upstreamRaw)
+			return nil, fmt.Errorf("%w: '%v' has no tag", ErrBadUpstreamFormat, upstreamRaw)
 		}
 		var u *url.URL
 		u, err = url.Parse(link)
 		if err != nil {
-			return nil, fmt.Errorf("%w: %v", BadUpstreamFormatError, err)
+			return nil, fmt.Errorf("%w: %v", ErrBadUpstreamFormat, err)
 		}
 		r := &UpstreamResolver{
 			Raw:     u,
diff --git a/component/dns/upstream.go b/component/dns/upstream.go
index 17806d0..2595707 100644
--- a/component/dns/upstream.go
+++ b/component/dns/upstream.go
@@ -20,7 +20,7 @@ import (
 )
 
 var (
-	FormatError = fmt.Errorf("format error")
+	ErrFormat = fmt.Errorf("format error")
 )
 
 type UpstreamScheme string
@@ -75,7 +75,7 @@ type Upstream struct {
 func NewUpstream(ctx context.Context, upstream *url.URL, resolverNetwork string) (up *Upstream, err error) {
 	scheme, hostname, port, err := ParseRawUpstream(upstream)
 	if err != nil {
-		return nil, fmt.Errorf("%w: %v", FormatError, err)
+		return nil, fmt.Errorf("%w: %v", ErrFormat, err)
 	}
 
 	systemDns, err := netutils.SystemDns()
diff --git a/component/outbound/dialer_group.go b/component/outbound/dialer_group.go
index d25f2f1..78437bf 100644
--- a/component/outbound/dialer_group.go
+++ b/component/outbound/dialer_group.go
@@ -16,7 +16,7 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
-var NoAliveDialerError = fmt.Errorf("no alive dialer")
+var ErrNoAliveDialer = fmt.Errorf("no alive dialer")
 
 type DialerGroup struct {
 	netproxy.Dialer
@@ -226,14 +226,14 @@ func (d *DialerGroup) MustGetAliveDialerSet(typ *dialer.NetworkType) *dialer.Ali
 func (g *DialerGroup) Select(networkType *dialer.NetworkType, strictIpVersion bool) (d *dialer.Dialer, latency time.Duration, err error) {
 	policy := g.selectionPolicy
 	d, latency, err = g._select(networkType, policy)
-	if !strictIpVersion && errors.Is(err, NoAliveDialerError) {
+	if !strictIpVersion && errors.Is(err, ErrNoAliveDialer) {
 		networkType.IpVersion = (consts.IpVersion_X - networkType.IpVersion.ToIpVersionType()).ToIpVersionStr()
 		return g._select(networkType, policy)
 	}
 	if err == nil {
 		return d, latency, nil
 	}
-	if errors.Is(err, NoAliveDialerError) && len(g.Dialers) == 1 {
+	if errors.Is(err, ErrNoAliveDialer) && len(g.Dialers) == 1 {
 		// There is only one dialer in this group. Just choose it instead of return error.
 		if d, _, err = g._select(networkType, &DialerSelectionPolicy{
 			Policy:     consts.DialerSelectionPolicy_Fixed,
@@ -256,7 +256,7 @@ func (g *DialerGroup) _select(networkType *dialer.NetworkType, policy *DialerSel
 		d := a.GetRand()
 		if d == nil {
 			// No alive dialer.
-			return nil, time.Hour, NoAliveDialerError
+			return nil, time.Hour, ErrNoAliveDialer
 		}
 		return d, 0, nil
 
@@ -272,7 +272,7 @@ func (g *DialerGroup) _select(networkType *dialer.NetworkType, policy *DialerSel
 		d, latency := a.GetMinLatency()
 		if d == nil {
 			// No alive dialer.
-			return nil, time.Hour, NoAliveDialerError
+			return nil, time.Hour, ErrNoAliveDialer
 		}
 		return d, latency, nil
 
diff --git a/component/sniffing/http.go b/component/sniffing/http.go
index a2476c0..b523bfc 100644
--- a/component/sniffing/http.go
+++ b/component/sniffing/http.go
@@ -17,7 +17,7 @@ import (
 func (s *Sniffer) SniffHttp() (d string, err error) {
 	// First byte should be printable.
 	if s.buf.Len() == 0 || !unicode.IsPrint(rune(s.buf.Bytes()[0])) {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 
 	// Search method.
@@ -27,10 +27,10 @@ func (s *Sniffer) SniffHttp() (d string, err error) {
 	}
 	method, _, found := bytes.Cut(search, []byte(" "))
 	if !found {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 	if !common.IsValidHttpMethod(string(method)) {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 
 	// Now we assume it is an HTTP packet. We should not return NotApplicableError after here.
@@ -63,5 +63,5 @@ func (s *Sniffer) SniffHttp() (d string, err error) {
 			return strings.TrimSpace(string(value)), nil
 		}
 	}
-	return "", NotFoundError
+	return "", ErrNotFound
 }
diff --git a/component/sniffing/internal/quicutils/relocation.go b/component/sniffing/internal/quicutils/relocation.go
index b00ab7b..297d590 100644
--- a/component/sniffing/internal/quicutils/relocation.go
+++ b/component/sniffing/internal/quicutils/relocation.go
@@ -12,8 +12,8 @@ import (
 )
 
 var (
-	UnknownFrameTypeError = fmt.Errorf("unknown frame type")
-	OutOfRangeError       = fmt.Errorf("index out of range")
+	ErrUnknownFrameType = fmt.Errorf("unknown frame type")
+	ErrOutOfRange       = fmt.Errorf("index out of range")
 )
 
 const (
@@ -78,7 +78,7 @@ func ReassembleCryptos(offsets []*CryptoFrameOffset, newPayload []byte) (newOffs
 
 func ExtractCryptoFrameOffset(remainder []byte, transportOffset int) (offset *CryptoFrameOffset, frameSize int, err error) {
 	if len(remainder) == 0 {
-		return nil, 0, fmt.Errorf("frame has no length: %w", OutOfRangeError)
+		return nil, 0, fmt.Errorf("frame has no length: %w", ErrOutOfRange)
 	}
 	frameType, nextField, err := BigEndianUvarint(remainder)
 	if err != nil {
@@ -111,7 +111,7 @@ func ExtractCryptoFrameOffset(remainder []byte, transportOffset int) (offset *Cr
 	case Quic_FrameType_ConnectionClose, Quic_FrameType_ConnectionClose2:
 		return nil, 0, fmt.Errorf("connection closed: %w", fs.ErrClosed)
 	default:
-		return nil, 0, fmt.Errorf("%w: %v", UnknownFrameTypeError, frameType)
+		return nil, 0, fmt.Errorf("%w: %v", ErrUnknownFrameType, frameType)
 	}
 }
 
diff --git a/component/sniffing/quic.go b/component/sniffing/quic.go
index 988344a..58eeb3d 100644
--- a/component/sniffing/quic.go
+++ b/component/sniffing/quic.go
@@ -43,16 +43,16 @@ func (s *Sniffer) SniffQuic() (d string, err error) {
 		s.quicCryptos, nextBlock, err = sniffQuicBlock(s.quicCryptos, nextBlock)
 		if err != nil {
 			// If block is not a quic block, return it.
-			if errors.Is(err, NotApplicableError) {
+			if errors.Is(err, ErrNotApplicable) {
 				// But if we have found quic block before, correct it.
 				if isQuic {
-					return "", NotFoundError
+					return "", ErrNotFound
 				}
 				return "", err
 			}
 			if errors.Is(err, fs.ErrClosed) {
 				// ConnectionClose sniffed.
-				return "", NotFoundError
+				return "", ErrNotFound
 			}
 			return "", err
 		}
@@ -67,7 +67,7 @@ func (s *Sniffer) SniffQuic() (d string, err error) {
 	sni, err := extractSniFromTls(quicutils.NewLinearLocator(s.quicCryptos))
 	if err != nil {
 		s.needMore = true
-		return "", NotFoundError
+		return "", ErrNotFound
 	}
 	return sni, nil
 }
@@ -78,17 +78,17 @@ func sniffQuicBlock(cryptos []*quicutils.CryptoFrameOffset, buf []byte) (new []*
 	const dstConnIdPos = 6
 	boundary := dstConnIdPos
 	if len(buf) < boundary {
-		return nil, nil, NotApplicableError
+		return nil, nil, ErrNotApplicable
 	}
 	// Check flag.
 	// Long header: 4 bits masked
 	// High 4 bits are not protected, so we can access QuicFlag_HeaderForm and QuicFlag_LongPacketType without decryption.
 	protectedFlag := buf[0]
 	if ((protectedFlag >> QuicFlag_HeaderForm) & 0b11) != QuicFlag_HeaderForm_LongHeader {
-		return nil, nil, NotApplicableError
+		return nil, nil, ErrNotApplicable
 	}
 	if ((protectedFlag >> QuicFlag_LongPacketType) & 0b11) != QuicFlag_LongPacketType_Initial {
-		return nil, nil, NotApplicableError
+		return nil, nil, ErrNotApplicable
 	}
 
 	// Skip version.
@@ -96,37 +96,37 @@ func sniffQuicBlock(cryptos []*quicutils.CryptoFrameOffset, buf []byte) (new []*
 	destConnIdLength := int(buf[boundary-1])
 	boundary += destConnIdLength + 1 // +1 because next field has 1B length
 	if len(buf) < boundary {
-		return nil, nil, NotApplicableError
+		return nil, nil, ErrNotApplicable
 	}
 	destConnId := buf[dstConnIdPos : dstConnIdPos+destConnIdLength]
 
 	srcConnIdLength := int(buf[boundary-1])
 	boundary += srcConnIdLength + quicutils.MaxVarintLen64 // The next fields may have quic.MaxVarintLen64 bytes length
 	if len(buf) < boundary {
-		return nil, nil, NotApplicableError
+		return nil, nil, ErrNotApplicable
 	}
 	tokenLength, n, err := quicutils.BigEndianUvarint(buf[boundary-quicutils.MaxVarintLen64:])
 	if err != nil {
-		return nil, nil, NotApplicableError
+		return nil, nil, ErrNotApplicable
 	}
 	boundary = boundary - quicutils.MaxVarintLen64 + n      // Correct boundary.
 	boundary += int(tokenLength) + quicutils.MaxVarintLen64 // Next fields may have quic.MaxVarintLen64 bytes length
 	if len(buf) < boundary {
-		return nil, nil, NotApplicableError
+		return nil, nil, ErrNotApplicable
 	}
 	// https://datatracker.ietf.org/doc/html/rfc9000#name-variable-length-integer-enc
 	length, n, err := quicutils.BigEndianUvarint(buf[boundary-quicutils.MaxVarintLen64:])
 	if err != nil {
-		return nil, nil, NotApplicableError
+		return nil, nil, ErrNotApplicable
 	}
 	boundary = boundary - quicutils.MaxVarintLen64 + n // Correct boundary.
 	blockEnd := boundary + int(length)
 	if len(buf) < blockEnd {
-		return nil, nil, NotApplicableError
+		return nil, nil, ErrNotApplicable
 	}
 	boundary += quicutils.MaxPacketNumberLength
 	if len(buf) < boundary {
-		return nil, nil, NotApplicableError
+		return nil, nil, ErrNotApplicable
 	}
 	header := buf[:boundary]
 	// Decrypt protected Packets.
@@ -144,7 +144,7 @@ func sniffQuicBlock(cryptos []*quicutils.CryptoFrameOffset, buf []byte) (new []*
 	}()
 	plaintext, err := quicutils.DecryptQuic_(header, blockEnd, destConnId)
 	if err != nil {
-		return nil, nil, NotApplicableError
+		return nil, nil, ErrNotApplicable
 	}
 	// Now, we confirm it is exact a quic frame.
 	// After here, we should not return NotApplicableError.
@@ -153,7 +153,7 @@ func sniffQuicBlock(cryptos []*quicutils.CryptoFrameOffset, buf []byte) (new []*
 		if errors.Is(err, fs.ErrClosed) {
 			return nil, nil, err
 		}
-		return nil, buf[blockEnd:], NotFoundError
+		return nil, buf[blockEnd:], ErrNotFound
 	}
 	return new, buf[blockEnd:], nil
 }
diff --git a/component/sniffing/sniffer.go b/component/sniffing/sniffer.go
index d1d3c5a..064064c 100644
--- a/component/sniffing/sniffer.go
+++ b/component/sniffing/sniffer.go
@@ -70,11 +70,11 @@ func sniffGroup(sniffs ...sniff) (d string, err error) {
 		if err == nil {
 			return d, nil
 		}
-		if err != NotApplicableError {
+		if err != ErrNotApplicable {
 			return "", err
 		}
 	}
-	return "", NotApplicableError
+	return "", ErrNotApplicable
 }
 
 func (s *Sniffer) SniffTcp() (d string, err error) {
@@ -100,14 +100,14 @@ func (s *Sniffer) SniffTcp() (d string, err error) {
 				return "", s.dataError
 			}
 		case <-s.ctx.Done():
-			return "", NotApplicableError
+			return "", ErrNotApplicable
 		}
 	} else {
 		close(s.dataReady)
 	}
 
 	if s.buf.Len() == 0 {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 
 	return sniffGroup(
@@ -125,7 +125,7 @@ func (s *Sniffer) SniffUdp() (d string, err error) {
 	close(s.dataReady)
 
 	if s.buf.Len() == 0 {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 
 	return sniffGroup(
diff --git a/component/sniffing/sniffing.go b/component/sniffing/sniffing.go
index 3128a76..9803b28 100644
--- a/component/sniffing/sniffing.go
+++ b/component/sniffing/sniffing.go
@@ -11,9 +11,9 @@ import (
 )
 
 var (
-	Error              = fmt.Errorf("sniffing error")
-	NotApplicableError = fmt.Errorf("%w: not applicable", Error)
-	NotFoundError      = fmt.Errorf("%w: not found", Error)
+	Error            = fmt.Errorf("sniffing error")
+	ErrNotApplicable = fmt.Errorf("%w: not applicable", Error)
+	ErrNotFound      = fmt.Errorf("%w: not found", Error)
 )
 
 func IsSniffingError(err error) bool {
diff --git a/component/sniffing/tls.go b/component/sniffing/tls.go
index 1ea4f38..b5f9801 100644
--- a/component/sniffing/tls.go
+++ b/component/sniffing/tls.go
@@ -31,17 +31,17 @@ func (s *Sniffer) SniffTls() (d string, err error) {
 	// https://www.rfc-editor.org/rfc/rfc8446#page-27
 	boundary := 5
 	if s.buf.Len() < boundary {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 
 	if s.buf.Bytes()[0] != ContentType_HandShake || (!bytes.Equal(s.buf.Bytes()[1:3], Version_Tls1_0) && !bytes.Equal(s.buf.Bytes()[1:3], Version_Tls1_2)) {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 
 	length := int(binary.BigEndian.Uint16(s.buf.Bytes()[3:5]))
 	search := s.buf.Bytes()[5:]
 	if len(search) < length {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 	return extractSniFromTls(quicutils.BuiltinBytesLocator(search[:length]))
 }
@@ -49,7 +49,7 @@ func (s *Sniffer) SniffTls() (d string, err error) {
 func extractSniFromTls(search quicutils.Locator) (sni string, err error) {
 	boundary := 39
 	if search.Len() < boundary {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 	// Transport Layer Security (TLS) Extensions: Extension Definitions
 	// https://www.rfc-editor.org/rfc/rfc6066#page-5
@@ -58,17 +58,17 @@ func extractSniFromTls(search quicutils.Locator) (sni string, err error) {
 		return "", err
 	}
 	if b[0] != HandShakeType_Hello {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 
 	// Three bytes length.
 	length2 := (int(b[1]) << 16) + (int(b[2]) << 8) + int(b[3])
 	if search.Len() > length2+4 {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 
 	if !bytes.Equal(b[4:], Version_Tls1_2) {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 
 	// Skip 32 bytes random.
@@ -79,7 +79,7 @@ func extractSniFromTls(search quicutils.Locator) (sni string, err error) {
 	}
 	boundary += int(sessionIdLength) + 2 // +2 because the next field has 2B length
 	if search.Len() < boundary || search.Len() < boundary {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 
 	b, err = search.Range(boundary-2, boundary)
@@ -89,7 +89,7 @@ func extractSniFromTls(search quicutils.Locator) (sni string, err error) {
 	cipherSuiteLength := int(binary.BigEndian.Uint16(b))
 	boundary += int(cipherSuiteLength) + 1 // +1 because the next field has 1B length
 	if search.Len() < boundary || search.Len() < boundary {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 
 	compressMethodsLength, err := search.At(boundary - 1)
@@ -98,7 +98,7 @@ func extractSniFromTls(search quicutils.Locator) (sni string, err error) {
 	}
 	boundary += int(compressMethodsLength) + 2 // +2 because the next field has 2B length
 	if search.Len() < boundary || search.Len() < boundary {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 
 	b, err = search.Range(boundary-2, boundary)
@@ -108,7 +108,7 @@ func extractSniFromTls(search quicutils.Locator) (sni string, err error) {
 	extensionsLength := int(binary.BigEndian.Uint16(b))
 	boundary += extensionsLength + 0 // +0 because our search ends
 	if search.Len() < boundary || search.Len() < boundary {
-		return "", NotApplicableError
+		return "", ErrNotApplicable
 	}
 	// Search SNI
 	extensions, err := search.Slice(boundary-extensionsLength, boundary)
@@ -123,7 +123,7 @@ func findSniExtension(search quicutils.Locator) (d string, err error) {
 	var b []byte
 	for {
 		if i+4 >= search.Len() {
-			return "", NotFoundError
+			return "", ErrNotFound
 		}
 		b, err = search.Range(i, i+4)
 		if err != nil {
@@ -134,7 +134,7 @@ func findSniExtension(search quicutils.Locator) (d string, err error) {
 
 		iNextField := i + 4 + extLength
 		if iNextField > search.Len() {
-			return "", NotApplicableError
+			return "", ErrNotApplicable
 		}
 		if typ == TlsExtension_ServerName {
 			b, err = search.Range(i+4, i+6)
@@ -143,7 +143,7 @@ func findSniExtension(search quicutils.Locator) (d string, err error) {
 			}
 			sniLen := int(binary.BigEndian.Uint16(b))
 			if extLength < sniLen+2 {
-				return "", NotApplicableError
+				return "", ErrNotApplicable
 			}
 			// Search HostName type SNI.
 			for j, indicatorLen := i+6, 0; j+3 <= iNextField; j += indicatorLen {
@@ -156,7 +156,7 @@ func findSniExtension(search quicutils.Locator) (d string, err error) {
 					continue
 				}
 				if j+3+indicatorLen > iNextField {
-					return "", NotApplicableError
+					return "", ErrNotApplicable
 				}
 				b, err = search.Range(j+3, j+3+indicatorLen)
 				if err != nil {
diff --git a/config/config_merger.go b/config/config_merger.go
index 80d9106..f2158d2 100644
--- a/config/config_merger.go
+++ b/config/config_merger.go
@@ -18,7 +18,7 @@ import (
 )
 
 var (
-	CircularIncludeError = fmt.Errorf("circular include is not allowed")
+	ErrCircularInclude = fmt.Errorf("circular include is not allowed")
 )
 
 type Merger struct {
@@ -51,7 +51,7 @@ func (m *Merger) readEntry(entry string) (err error) {
 	// Check circular include.
 	_, exist := m.entryToSectionMap[entry]
 	if exist {
-		return CircularIncludeError
+		return ErrCircularInclude
 	}
 
 	// Check filename
@@ -121,7 +121,7 @@ func unsqueezeEntries(patternEntries []string) (unsqueezed []string, err error)
 func (m *Merger) dfsMerge(entry string, fatherEntry string) (err error) {
 	// Read entry and check circular include.
 	if err = m.readEntry(entry); err != nil {
-		if errors.Is(err, CircularIncludeError) {
+		if errors.Is(err, ErrCircularInclude) {
 			return fmt.Errorf("%w: %v -> %v -> ... -> %v", err, fatherEntry, entry, fatherEntry)
 		}
 		return err
diff --git a/control/dns_control.go b/control/dns_control.go
index a0787fe..4ddcde9 100644
--- a/control/dns_control.go
+++ b/control/dns_control.go
@@ -47,7 +47,7 @@ const (
 )
 
 var (
-	UnsupportedQuestionTypeError = fmt.Errorf("unsupported question type")
+	ErrUnsupportedQuestionType = fmt.Errorf("unsupported question type")
 )
 
 var (