[FIXED] Inboxes suffix would contain many zeros

This was introduced by PR #767
when the nuidSize was used instead of replySuffixLen to just build
the reply suffix. This meant that the suffix part with 22 characters
long and had lots of zeros at the end.

Added a test to make sure we don't break that in the future.

Signed-off-by: Ivan Kozlovic <ivan@synadia.com>

go_test.mod

@@ -4,7 +4,7 @@ go 1.16
 
 require (
 	github.com/golang/protobuf v1.4.2
-	github.com/nats-io/nats-server/v2 v2.3.5-0.20210825221009-41a253dabb43
+	github.com/nats-io/nats-server/v2 v2.4.1-0.20210831212757-2539bbb957ef
 	github.com/nats-io/nkeys v0.3.0
 	github.com/nats-io/nuid v1.0.1
 	google.golang.org/protobuf v1.23.0

go_test.sum

@@ -19,9 +19,9 @@ github.com/nats-io/jwt v1.2.2 h1:w3GMTO969dFg+UOKTmmyuu7IGdusK+7Ytlt//OYH/uU=
 github.com/nats-io/jwt v1.2.2/go.mod h1:/xX356yQA6LuXI9xWW7mZNpxgF2mBmGecH+Fj34sP5Q=
 github.com/nats-io/jwt/v2 v2.0.3 h1:i/O6cmIsjpcQyWDYNcq2JyZ3/VTF8SJ4JWluI5OhpvI=
 github.com/nats-io/jwt/v2 v2.0.3/go.mod h1:VRP+deawSXyhNjXmxPCHskrR6Mq50BqpEI5SEcNiGlY=
-github.com/nats-io/nats-server/v2 v2.3.5-0.20210825221009-41a253dabb43 h1:Sbb4QxNsccsPERg0C7uQX7/xgOCOTMIvDH9Ytb5MXsU=
-github.com/nats-io/nats-server/v2 v2.3.5-0.20210825221009-41a253dabb43/go.mod h1:jgHRB+EfZisUr6j50/g7Gcah7AR8qtk3as42DJmESCk=
-github.com/nats-io/nats.go v1.11.1-0.20210819195927-9053aa4200f0/go.mod h1:BPko4oXsySz4aSWeFgOHLZs3G4Jq4ZAyE6/zMCxRT6w=
+github.com/nats-io/nats-server/v2 v2.4.1-0.20210831212757-2539bbb957ef h1:fVi/sPmt1MjO1bA4M4jFlrCs9DYuZbpHPeKr7IQRM2Q=
+github.com/nats-io/nats-server/v2 v2.4.1-0.20210831212757-2539bbb957ef/go.mod h1:TUAhMFYh1VISyY/D4WKJUMuGHg8yHtoUTuxkbiej1lc=
+github.com/nats-io/nats.go v1.12.0/go.mod h1:BPko4oXsySz4aSWeFgOHLZs3G4Jq4ZAyE6/zMCxRT6w=
 github.com/nats-io/nkeys v0.2.0/go.mod h1:XdZpAbhgyyODYqjTawOnIOI7VlbKSarI9Gfy1tqEu/s=
 github.com/nats-io/nkeys v0.3.0 h1:cgM5tL53EvYRU+2YLXIK0G2mJtK12Ft9oeooSZMA2G8=
 github.com/nats-io/nkeys v0.3.0/go.mod h1:gvUNGjVcM2IPr5rCsRsC6Wb3Hr2CQAm08dsxtV6A5y4=

nats.go

@@ -3566,6 +3566,7 @@ func (nc *Conn) oldRequest(subj string, hdr, data []byte, timeout time.Duration)
 const (
 	InboxPrefix    = "_INBOX."
 	inboxPrefixLen = len(InboxPrefix)
+	replySuffixLen = 8 // Gives us 62^8
 	rdigits        = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
 	base           = 62
 )
@@ -3615,7 +3616,7 @@ func (nc *Conn) newRespInbox() string {
 	sb.WriteString(nc.respSubPrefix)
 
 	rn := nc.respRand.Int63()
-	for i := 0; i < nuidSize; i++ {
+	for i := 0; i < replySuffixLen; i++ {
 		sb.WriteByte(rdigits[rn%base])
 		rn /= base
 	}

nats_test.go

@@ -2702,3 +2702,37 @@ func TestCustomInboxPrefix(t *testing.T) {
 		t.Fatalf("did not receive ok: %q", resp.Data)
 	}
 }
+
+func TestRespInbox(t *testing.T) {
+	s := RunServerOnPort(-1)
+	defer s.Shutdown()
+
+	nc, err := Connect(s.ClientURL())
+	if err != nil {
+		t.Fatalf("Expected to connect to server, got %v", err)
+	}
+	defer nc.Close()
+
+	if _, err := nc.Subscribe("foo", func(msg *Msg) {
+		lastDot := strings.LastIndex(msg.Reply, ".")
+		if lastDot == -1 {
+			msg.Respond([]byte(fmt.Sprintf("Invalid reply subject: %q", msg.Reply)))
+			return
+		}
+		lastToken := msg.Reply[lastDot+1:]
+		if len(lastToken) != replySuffixLen {
+			msg.Respond([]byte(fmt.Sprintf("Invalid last token: %q", lastToken)))
+			return
+		}
+		msg.Respond(nil)
+	}); err != nil {
+		t.Fatalf("subscribe failed: %s", err)
+	}
+	resp, err := nc.Request("foo", []byte("check inbox"), time.Second)
+	if err != nil {
+		t.Fatalf("Request failed: %v", err)
+	}
+	if len(resp.Data) > 0 {
+		t.Fatalf("Error: %s", resp.Data)
+	}
+}