Add a comment explaining why we sort the Qops

3 files changed, 6 insertions, 3 deletions

diff --git a/internal/rpc/kerberos.go b/internal/rpc/kerberos.go
index d505536..c34ce8c 100644
--- a/internal/rpc/kerberos.go
+++ b/internal/rpc/kerberos.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net"
 	"regexp"
+	"sort"
 
 	hadoop "github.com/colinmarc/hdfs/v2/internal/protocol/hadoop_common"
 	"github.com/colinmarc/hdfs/v2/internal/sasl"
@@ -62,7 +63,11 @@ func (c *NamenodeConnection) doKerberosHandshake() error {
 			return err
 		}
 
+		// Some versions of HDP 3.x expect us to pick the highest Qop, and
+		// return a malformed response otherwise.
+		sort.Sort(challenge.Qop)
 		qop := challenge.Qop[0]
+
 		switch qop {
 		case sasl.QopPrivacy, sasl.QopIntegrity:
 			// Switch to SASL RPC handler
diff --git a/internal/sasl/challenge.go b/internal/sasl/challenge.go
index cc3f1d4..9e73fa6 100644
--- a/internal/sasl/challenge.go
+++ b/internal/sasl/challenge.go
@@ -4,7 +4,6 @@ import (
 	"errors"
 	"fmt"
 	"regexp"
-	"sort"
 	"strings"
 )
 
@@ -74,7 +73,6 @@ func ParseChallenge(challenge []byte) (*Challenge, error) {
 			ch.Nonce = val
 		case "qop":
 			ch.Qop = strings.Split(val, ",")
-			sort.Sort(ch.Qop)
 		case "charset":
 			ch.Charset = val
 		case "cipher":
diff --git a/internal/transfer/block_write_stream.go b/internal/transfer/block_write_stream.go
index f657dde..0fa2ba8 100644
--- a/internal/transfer/block_write_stream.go
+++ b/internal/transfer/block_write_stream.go
@@ -290,7 +290,7 @@ Acks:
 	// Once we've seen an error, just keep reading packets off the channel (but
 	// not off the socket) until the writing thread figures it out. If we don't,
 	// the upstream thread could deadlock waiting for the channel to have space.
-	for _ = range s.packets {
+	for range s.packets {
 	}
 }