lint(errorlint): handle wrapped errors

Enable errorlint and preserve wrapped error chains so runtime checks
and tests classify failures correctly. This also makes Route53
surface insert failures instead of silently dropping them.

Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>

core/dnsserver/server_grpc_test.go

@@ -457,7 +457,7 @@ func TestGRPCResponseTsigStatusReturnsStoredStatus(t *testing.T) {
 		tsigStatus: want,
 	}
 
-	if got := r.TsigStatus(); got != want {
+	if got := r.TsigStatus(); !errors.Is(got, want) {
 		t.Fatalf("TsigStatus() = %v, want %v", got, want)
 	}
 }

core/dnsserver/server_https_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"crypto/tls"
+	"errors"
 	"io"
 	"net"
 	"net/http"
@@ -579,7 +580,7 @@ func TestServeHTTPAcceptsValidTSIG(t *testing.T) {
 
 func TestDoHWriterTsigStatusReturnsStoredStatus(t *testing.T) {
 	dw := &DoHWriter{tsigStatus: dns.ErrSecret}
-	if dw.TsigStatus() != dns.ErrSecret {
+	if !errors.Is(dw.TsigStatus(), dns.ErrSecret) {
 		t.Fatal("expected TsigStatus to return stored tsigStatus")
 	}
 }

core/dnsserver/server_quic.go

@@ -191,7 +191,7 @@ func (s *ServerQUIC) serveQUICStream(stream *quic.Stream, conn *quic.Conn) {
 	// io.EOF does not really mean that there's any error, it is just
 	// the STREAM FIN indicating that there will be no data to read
 	// anymore from this stream.
-	if err != nil && err != io.EOF {
+	if err != nil && !errors.Is(err, io.EOF) {
 		s.closeQUICConn(conn, DoQCodeProtocolError)
 
 		return

core/dnsserver/server_quic_test.go

@@ -455,7 +455,7 @@ func TestDoQWriterTsigStatusReturnsStoredStatus(t *testing.T) {
 		tsigStatus: want,
 	}
 
-	if got := w.TsigStatus(); got != want {
+	if got := w.TsigStatus(); !errors.Is(got, want) {
 		t.Fatalf("TsigStatus() = %v, want %v", got, want)
 	}
 }